4/12/23

#194 pink salmon

Pink Salmon, Oncorhynchus gorbuscha, are the smallest and most abundant species of Pacific Salmon. Pink salmon are found from the Sacramento River in California to the Mackenzie River in Canada and from the Lena River in Siberia to Korea and Honshu in Japan. They are also referred to as humpback salmon because males develop a pronounced humped back during their spawning migration. They are anadromous fish, meaning they migrate from freshwater to oceans when they hatch and back to freshwater to spawn. Males and females develop a vivid pink colouration during this time. Once upstream, females use their tails to dig a nest in the gravel of the streambed where they deposit their eggs. Males fertilise the eggs as they fall into the nest in the gravel. Small fish, birds and mammals feed on pink salmon in both freshwater and in the ocean. Bears feed on adult pink salmon when they are making their way up rivers to spawn. Pink salmon have immense ecological importance, providing sustenance for an array of different species and nutrients to the ecosystem when their bodies decay. In November, droughts across North America killed thousands of Pacific Salmon. They were trying to migrate upstream to their spawning grounds but could not make it due to unprecedented low water levels. Low water levels in streams and rivers combined with higher water temperatures can kill juvenile salmon and make it difficult for adults to swim upriver to their spawning grounds. Pink salmon are threatened by barriers to migration, habitat loss and climate change is compounding these existing pressures. 

20/11/23

#192 Chinese fire belly newt

The Chinese fire belly newt, Cynops orientalis, is found in the lower reaches of the Yangtze River in the pools, ponds and paddy fields of Southern China. It has a bright red and orange belly signals predators to stay away, rightfully so as they release a toxin from their skin that can paralyse and even kill predators that try to consume them. During the day, they hide in the water between vegetation and rocks occasionally coming up to the surface to breathe. They can be found up to 2,000m above sea level, hibernating during colder months. During mating season, they can develop a blue sheen to their tail to attract a mate. Fire belly newts flick their tails to attract a mate. Between the months of March and July, they lay and hide their eggs in the water between aquatic vegetation. The larvae develop in the water and complete metamorphosis within a year.  They eat aquatic worms and insect larvae. Chinese fire belly newts are collected for local consumption and the international pet trade. Populations are suspected to be declining due to habitat degradation. Like many other freshwater species, more research to understand the population health of Chinese fire belly newts is needed.

6/11//23

#190 Redtail catfish

Native to the Amazon, Orinoco and Essequibo river basins, the redtail catfish, Phractocephalus hemioliopterus, get their name from their orange-red dorsal and caudal fins but it has several different names throughout South America. In Guayna, it is known as the banana catfish, in Brazil as pirarara and in Venezuela as cajaro. The redtail catfish is one of the three giant catfish species in the Amazon next to the piraiba and the jau. They are bottom-dwellers that inhabit large rivers, lakes and streams, remaining motionless during the day and feeding at night on crustaceans and fallen fruit. Living fossils, their genus dates back to 13.5 million years old! Red tailed catfish are known for their long whiskers which have chemical reception cells used to sense smell. They can grow up to 56 kg big and live to 15 years old! They communicate with a clicking sound to ward off any potential danger such as river dolphins. Catfish make up the majority of river dolphins’ diet. However, mercury intake from catfish species threatens the health of river dolphins. It is important that we safeguard this species to in turn safeguard river dolphin populations.

23/10/23

#188 River Dolphins

River dolphins are extraordinary. They are the apex predators of some of the world’s largest river systems and are important indicators of the health of rivers. Where river dolphin populations are thriving, it is likely the whole freshwater system is flourishing. But all six species of river dolphins are threatened with extinction. A seventh river dolphin species, the Chinese river dolphin or baiji, was declared extinct in 2007, reminding us of how precarious these dolphins’ survival can be. River fragmentation due to water infrastructure divides populations; dolphins become entangled and killed in fishing gear; and water pollution affects the animals’ health. That is why on October 24th, we are bringing together the river dolphin range states to sign a historic Global Declaration for River Dolphins - spearheaded by WWF. The Declaration will help to accelerate action to save the world’s six remaining species of river dolphin - and enhance the health of their great rivers, benefiting the people and nature that depend on them. We need to safeguard these iconic animals that benefit both people and nature that depend on their rivers.

9/10/23

#186 Climbing Galaxias

Native to south-eastern parts of Australia and all of New Zealand, the Climbing Galaxias, Galaxias brevipinnis, is known for its amazing ability to climb steep surfaces such as waterfalls and wet rocks using their downward facing pectoral and pelvic fins to “wriggle” upwards like lizards- making it one of the furthest inland penetrating fish species in New Zealand. A nocturnal species, Climbing Galaxias feed at night on aquatic invertebrates such as mayflies and small crustaceans. They lay eggs towards the surface close to vegetation and once hatched, the larvae are swept downstream into marine environments where they spend four to six months before returning back into estuarine and freshwater habitats. Threats to this species include artificial barriers to migration. Although climbing galaxias are known for their fantastic climbing skills, they struggle to navigate large and smooth man made barriers such as dams. In addition, habitat destruction, pollution of waterways, changes in catchment land use and the impacts of invasive non-native species are a risk to climbing galaxias. The natural distribution of this species is fragmented throughout its range most likely due to habitat fragmentation. There are currently no species specific conservation actions for this species. 

18/9/23

#184 Greater Flamingo

The largest living species of flamingo, the Greater Flamingo, Phoenicopterus roseus, reside in mudflats and shallow coastal lagoons from West Africa, throughout the Mediterranean to Southwest and South Asia in addition to sub-Saharan Africa. They nest and roost on sand banks, mudflats, islands or boggy, open shores. They eat crustaceans, molluscs, insects, small fish, aquatic plants and algae. Greater flamingos get their unique colour specifically from the brine shrimp and algae. They are gray-brown until the age of two. Their necks have 19 bones which give them a lot of flexibility - they eat upside down scooping their beaks into the water. A highly social species, they nest in large colonies. They are monogamous - only laying one egg per breeding season. Juveniles migrate in response to water level changes. Flamingos are a hardy species that can survive in extreme temperatures (from -30C to 48C) and can be found in both fresh and saltwater. They have a gland that filters out saltwater and they usually rinse in freshwater afterwards. To attract a female, males perform a complicated dance swinging out their wings in one direction and one leg in another direction. Once they have mated, they are partners for life. Males and females both produce crop milk - taking turns feeding their offspring. Water pollution and habitat loss threatens this species. Lowering water levels negatively affects their food sources. It is important that we continue to protect wetlands used by this species.

4/9/23

#182 Spotted Handfish

Once widespread across Tasmania, the Spotted Handfish, Brachionichthys hirsutus, is now only found in the estuary of the Derwent River - making it an incredibly rare species. These slow moving fish have highly adapted pectoral fins which appear like hands, allowing them to walk along the floor. They rarely swim, using their anal and pectoral fins to propel upwards when they do. Found in shallow sandy and shell bottoms, Spotted Handfish reside in estuaries with low wave intensity. Spotted handfish are ambush predatory; like anglerfish species they have a lure above their mouth that attracts their prey: amphipods, shrimps and worms. It is thought that his lure is also used by males when performing a courtship ritual to attract a mate during mating season. They have been assessed as Critically Endangered by the IUCN Red List of Threatened Species. It is believed that habitat destruction and bycatch led to severe population declines in the 1980’s. Now their main threat is water pollution and the invasive species, the Northern Pacific Sea Star, which not only threatens spotted handfish themselves but also their eggs. Conservation measures are underway. The Australian and Tasmanian governments prohibit the capture of this species and mandate the development and funding of a recovery plan for this species. In addition, the Derwent Estuary Program is regularly monitoring the water quality of this estuary.

21/8/23

#180 Eurasian Beaver

Eurasian beavers, Castor fiber, are found throughout Europe and Asia. Eurasian beavers are found in freshwater woodland environments including rivers, streams, lakes and swamps. They have orange teeth due to iron in their enamel giving them the strength to gnaw through wood. Strong swimmers, they can hold their breath for up to 15 minutes and can swim up to 8 km/h - that’s double the speed of a human! Beavers fight climate change by helping control the flow of water. The dams they build increase the storage of water upstream and can help to create drought and fire resistant landscapes. They store food in the autumn to help them survive the winter. Beavers are perhaps the most famous ‘ecosystem engineer’ as their dam building alters the habitat and makes new habitat. Their dams are a nature based solution that process nutrients, traps sediments and creates wetland and floodplain habitats. As a result of conservation efforts, the Eurasian beaver has shown good recovery across its range. The highest numbers are found in Europe - where over 85% of Eurasian beavers are found. However, Northern Asian populations are very small and remain under threat. Eurasian beavers are threatened by hunting, habitat loss, especially from deforestation, dams blocking migratory routes and pollution. Thus, it is imperative that we have conservation measures in place in both Europe and Asia, such as the Norfolk Rivers Trust Beaver Project that is funded and supported by WWF.

7/8/23

#178 Père David's Deer

Père David's deer, Elaphurus davidianus, also known as long-tailed deer or "four unlike," is endemic to China. Père David's deer is a large herbivore of the wetlands. They are good swimmers, preferring to live in the low-altitude swampy wetland with a mild climate. The wetland in the middle and lower reaches of the Yangtze River is an ideal habitat for them. Père David's deer have leathery tendon membranes that grow between their main hooves like duck flippers, which help with walking on muddy ground and swimming. They are a highly communal species. In summer, Père David's deer have a brownish-red coat; in winter, it is greyish-brown. Male deer have long horns, which are weapons for self-defence while female deer are hornless. Due to habitat loss and hunting, the wild Père David's deer became extinct in the 19th century and was listed as extinct in the wild by the IUCN Red List of Threatened Species. In 1865, a French zoologist and missionary, Pere David, discovered the deer in the Royal Hunting Park in Nanhaizi, Beijing. Since then, some of the deer have gone out of the country and stayed overseas. In 1894 and 1900, natural disasters and wars made the deer disappear from the Royal Parks and Gardens of the Qing Dynasty of China, and in the eight years before 1901, the 11th Duke of Belfort bought 18 Père David's deer from the Paris, Berlin, Cologne and Andean Zoological Gardens, and released them in his Ubonji Manor, so the population gradually recovered. After 1937, the deer from Ubonji began to be imported into zoos in some western countries for multi-point breeding. In the 1980s, the deer were reintroduced to the Nanhaizi Park in Beijing and the Dafeng Reserve in Jiangsu Province, China, where they were reintroduced to their native habitats to restore their breeding and wild populations. By 2022 there were more than 11,500 Père David's deer in China, of which nearly 5,000 are in wild populations. Currently, five wild populations of the deer have been restored in Jiangsu, Hubei, Hunan and Jiangxi provinces, where they were systematically released into nature and returned naturally to the wild in 1998. Further research needs to be conducted to assess the long-term viability of these existing wild populations.

24/7/23

#176 Atlantic Mudskipper

Native to the brackish waters of the West African coast from Senegal to Angola, Atlantic mudskippers, Periophthalmus barbarus, are found in muddy substrates in estuaries, lagoons and mangrove swamps. As amphibious air breathers, they can skip, climb and  crawl using their pelvic and pectoral fins outside of water in search of food. They come out to feed at low tide on crabs, insects and mangroves on the surface of the mud. At high tide, they nestle back underwater into their burrows. Males dig burrows down to 1m deep where the female lays her eggs and guard them until they hatch. Atlantic mudskippers are gill breathers; when they walk on land they hold water in their gills and in addition, absorb oxygen through their skin and oral mucous membranes. Like frogs and toads, their eyes are placed high on their heads, giving them the ability to avoid predators above such as birds. Mudskippers are living model organisms suitable for the study of the evolutionary transition from water to land. Their ability to walk on land gives them the ability to exploit a novel terrestrial habitat that is hostile to their aquatic ancestors. They are harvested for human consumption, bait and the aquarium pet trade. Atlantic mudskippers are threatened by coastal developments, water pollution and destructive fishing practices. No conservation practices are known to be in place for this species.

10/7/23

#174 Common Fire Salamander

Common Fire Salamander a.k.a. European salamander, Salamandra salamandra, is endemic to Europe from Portugal to Bulgaria from lowland areas to up to 2500m. They are found in wet, cool areas near well shaded brooks and small rivers. In ancient times, people believed they were born in fires. Their bright yellow spots act to deter predators by signalling their toxicity. Fire salamanders have a toxin that causes muscle convulsions, hypertension and hyperventilation in all predators, if consumed. This is also true for humans, their toxins are only a threat if ingested. When threatened,they spray the toxins from glands behind their eyes into the eyes or mouth of the predator. Toxins are also secreted from their skin if a predator tries to eat or touch it. If a predator succeeds at taking one of their limbs, it can quickly  grow a new one. Fire salamanders take in oxygen through their moist, permeable skin. Females lay their eggs in the water where they young will reside until their gills turn into lungs. Local populations in Spain and Italy have declined due to habitat loss, introduced predator species and increased aridity. In addition, pollution of breeding sites by agrochemicals and predation by invasive salmonid fishes and American Crayfish threaten this species. A severe decline has been reported in the Netherlands. Bsal is an emerging fungal pathogen affecting amphibians and has been detected in Europe. There is an urgent need for research on EU wide approach and implementation of action plans to address the threat of Bsal on these salamanders.

26/6/23

#172 Longnose gar

Found in large weedy lakes, backwaters and stagnant ponds, the Longnose Gar also known as Billy Gar, Lepisosteus osseus, is found on the North American Atlantic slope from the Delaware River, New Jersey to central Florida to Texas and a small part in Mexico. Longnose gars get their name from their overly long snouts, over twice the size of their heads. Gars have existed for 100 million years meaning they have been around since the time of dinosaurs. Their vascularized swim bladders allow them to breathe air which gives them the ability to survive in low oxygenated water. With razor sharp teeth, they feed on small fishes and crustaceans. Longnose gars are one of the fastest growing fish, growing six times faster than other common large freshwater fish and living 30+ years old. During the mating season, longnose gars migrate upstream to fast moving streams where they lay their eggs- laying up to 30,000 eggs! Gar eggs stick to aquatic plants and are toxic to animals and humans. Considered “trash fish” by some anglers, longnose gars have been left out to die on river banks due to their beliefs that they predate on popular sport fish and are unfit for consumption. The misunderstood longnose gar is an apex predator in aquatic ecosystems, important in maintaining stable fish populations and it’s fished more as a trophy fish than for consumption. Their thick scales, along with residing in schools protects them from predators. Their scales were valuable to Native Americans for tools, shields, arrowheads and ornaments. Native Americans consider the longnose gar a sacred fish - a symbol of strength and resilience. 

12/6/23

#170 American Manatee

The American Manatee, also known as the West Indian Manatee, Trichechus manatus, is more closely related to elephants than any marine mammal. The largest aggregation of American manatees can be found in central and south Florida, USA and are famous in Florida’s Crystal River. Undertaking seasonal migrations, manatees are not residents there year round. They come in the winter in search of warmer waters. Legend has it that when Christopher Colombus came to the Americas he caught a glimpse of three mermaids that were not as pretty as he imagined - it was thought that he was referring to manatees. Manatees' preferred habitats are shallow grass beds with deep channels that are easy to access. Manatees are an indicator species for healthy ecosystems, responsible for controlling mosquito populations and maintaining vegetative balance. Feeding solely on vegetation, manatees are herbivores, eating more than 1/10th of their weight in food everyday. Manatees are such slow moving animals, algae and barnacles can be found on their backs. Manatees do not have a neck vertebrate so they are unable to turn their neck the way humans do. Although they are able to survive in freshwater, estuaries and marine environments, American manatees depend on freshwater for osmoregulation. Calves are dependent on their mothers for one to two years. Quiet protected areas are crucial for resting and for mothers with their calves. About half of their deaths can be attributed to collisions with watercraft. They are also threatened by habitat loss, reduction in natural spring flows and water temperature change - 246 manatees died in Florida during an abnormally cold winter. They are defined as Vulnerable by the IUCN Red List of Threatened Species. 

29/5/23

#168 Hairy-nosed Otter

One of the rarest otter species, hairy-nosed otters, Lutra sumatrana, are endemic to Southeast Asia and have been found in small pockets of Myanmar, and in parts of Cambodia and Viet Nam. Their name comes from the hairs you see on the tip of their snout. They reside in lowland wetland forests such as peatswamp, tropical and Melaleuca forests as well as mangroves and rivers. Living solitary or in groups of up to four, hairy nosed otters spend most of their day hunting for prey. They feed on fish, molluscs, crustaceans and water snakes. With fully webbed feet and a muscular body, they are great swimmers! They have long sensitive whiskers that help them detect changes in water movement aiding in navigation and hunting underwater. But populations are declining rapidly due to habitat destruction such as forest clearance for palm oil plantations and trade-driven illegal hunting. In Cambodia and Vietnam, hunting otters is common practice. They are hunted for their meat, illegal wildlife trade and for medicinal use. The hairy-nosed otter is the rarest of the Asian otters, and one of the rarest otters species in the world. In 1998 they were declared extinct but in 1999 they were rediscovered in the peat swamp forests of Thailand. They are listed as Endangered by the IUCN Red List of Threatened Species. Even though they are protected in all the range countries, populations continue to decline. More studies on their ecology, behaviour & populations are needed.

15/5/23

#166 Slender-nosed Crocodile

Found in West and Central Africa, African slender nosed crocodiles can grow up to 4 metres long and weigh up to 220 kg. They reside in forested rivers and densely vegetated waters such as freshwater lagoons. With razor sharp teeth and powerful jaws well adapted to catching fish, they also consume birds, turtles and invertebrates. They hunt with just their eyes and nostrils above the surface. Their slender snouts act like tweezers - allowing them to get prey from small crevices. Swimming underwater using their tails, their eyes are protected by an extra set of semi transparent eyelids. Males show dominance by raising their bodies out of the water. Females show incredibly attentive prenatal care from helping the hatchlings out of their eggs. Once hatched, the female scoops the hatchlings into her jaw and carries them into the water. Incredibly wary  and susceptible to human disturbance, Africa slender nosed crocodiles are  listed as Critically Endangered by the IUCN Red List of Threatened Species. They are threatened by commercial skin hunting and habitat degradation.

1/5/23

#164 Water Lettuce

First discovered in the Nile near Lake Victoria, water lettuce a.k.a. water cabbage, Pistia stratiotes, gets its name from resembling a leafy vegetable. It is thought to have originated from South America or Africa. Seen floating on the surface of lakes and rivers, the roots of water lettuce are free floating. Thus, it does not rely on soil to grow. Thick soft leaves that form a rosette and small white and pale green flowers bloom from late summer to fall. It is a valuable oxygenator, removes pollutants from water and provides shade and shelter for fish. The species can remove pollutants through a process called phytoextraction - the absorption of organics, salts and metals into their tissues. Water lettuce has an efficiency of 80-90% removal of heavy metals, nitrates and phosphate from wastewater. It has the ability to prevent harmful algal blooms as it outcompetes algae for nutrients in freshwater and blocks sunlight. It is also used as a food source for cattle. Some believe water lettuce has medicinal properties and is used as a laxative, treatment of bladder complaints, kidney disease, tumours and skin disease. It is also used for making soap in West Tropical Africa and can be used as biofuel. Water lettuce is also a crucial food source for wildlife including fishes, waterbirds and Manatees.The species has  been grown as an ornamental for lakes, ponds and gardens and with so many valuable traits, humans have introduced this species into regions outside its native range. This has negatively impacted biodiversity in these areas by crowding out native plants and it is currently being considered for the EU's list of banned invasive species. 

17/4/23

#162 River Cooter

The River Cooter, Pseudemys concinna, is a freshwater turtle found in central and eastern United States and feeds exclusively on aquatic plants, grasses and algae. River cooters are easily spooked when approached and will quickly jump into the water. River cooters have large webbed feet which makes them excellent swimmers and gives them the ability to swim against strong currents. River cooters breathe underwater using a sac based on their tail called the cloaca bursae. This sac allows them to stay underwater for extended periods of time. During hibernation they can stay underwater at the bottom of lakes, rivers and ponds for up to two months! Generally solitary creatures, they sleep underwater under vegetation. However, they can also be seen basking on warm rocks and logs piled up on top of each other. They can live over 40 years old. Smaller than females, male cooters use extravagant displays to attract females, swimming around them and biting their backs. Small hatchling turtles are vulnerable and targeted by a variety of predators. River cooters are threatened by habitat loss, highway accidents and human consumption. They are also harvested from the wild and sold in pet stores.  More studies are needed to determine the population status and decline of this species. 

2/1/23

#160 Red river hog

The most colourful of the pig family, red river hogs spend most of their time wallowing in rivers, lakes and streams. Red River Hog, Potamochoerus porcus, is found near swamps and rivers in Africa from Senegal, through the Guinea-Congo forest and west of the Albertine Rift. Known for its reddish brown fur, both females and males have tusks from their canine teeth. They grunt or squeal to alarm others of predators in the area. Primarily nocturnal, they remain in densely covered areas during the day to avoid predators. Using their large muzzle to search for food in the soil, their diet consists mainly of roots, seeds and invertebrates. Red river hogs roam individually and in family groups ranging from 10-60. Strong swimmers, they can swim underwater holding their breath for up to 15 seconds. They mark their territory by using their tusks to scrape tree trunks. If threatened, they fight by butting heads. A highly adaptable species, red river hogs have been able to adjust to changing environmental conditions. Hunting has led to localised population declines and populations should be monitored in those areas. They are harvested for the bushmeat trade in most of Central Africa. In Senegal, sightings of red river hogs has become so rare that it is considered endangered and is a protected species by national law. More research on the population status of the red river hog is needed.

20/3/23

#158 American Mink

The American mink, Neovison vison, is native to  North America and can be found in a broad range of habitats including lakes, streams, rivers, swamps and marshes. It prefers densely vegetated areas and dens under stones or the roots of trees and self-dug burrows beside the water. They are fiercely territorial over their dens and are able to slip into narrow openings to pursue prey. American mink are nocturnal and feed on fish, crustaceans, rodents, birds and frogs. Strong swimmers, mink have partially webbed feet and a thick waterproof oily coat that allows them to stay in the water for long periods of time. When searching for food they are able to reach depths down to 30m deep! Mink are members of the mustelid family and are related to otters, weasels and badgers. They have also been seen climbing trees. They purr like a cat when they are happy and hiss and spray foul odour when they are threatened. They usually live alone and are only with their partners during mating season. Among the most valuable fur animals, they are commonly hunted for their fur. Most of the mink fur used in commerce is produced in farms. A negative outcome of the fur trade is that American mink have been introduced by humans outside their native range, including in Europe. The adaptations which mink successful predators in their native homelands of North America, can pose a serious threat to wildlife that did not evolve to live with them, and therefore they are considered a risk to native wildlife where they have been artificially introduced. In their native range American mink are an important part of the ecosystem, but habitat destruction such as alteration to vegetation along rivers and wetlands and water pollution threatens this species.

6/3/23

#156 Common Pipewort

Found in the shallow water of lakes, ponds, marshes, wetlands and slow moving rivers, the Common Pipewort, Eriocaulon aquaticum, a.k.a the seven angle pipewort has blooms of tiny flowers held up above the water line attracting pollinating insects. While many aquatic plants are wind or water pollinated, pipeworts have a nectar gland at the tip of each petal to attract pollinators. Widespread across North America and Canada, pipeworts have a tall leafless stem with a button-like white flower. The part of the plant submerged underwater provides a habitat for invertebrates, which are  in turn  a food source  for aquatic species. Beetles also feed on the roots and shoots. Their height depends on the water depth  it is growing in - up to several feet high! Pipeworts improve water quality by transporting oxygen to its underwater roots, stems and leaves. This oxygen leaks into surrounding spaces where microorganisms decompose organic wastes, very similar to a water treatment plant. Populations of pipeworts have declined globally, mainly threatened by shoreline development and pollution.

20/2/23

#154 Red Line Dwarf Cichlid

Native to the Orinoco Basin in South America, the Red Line Dwarf Cichlid Dwarf, Apistogramma hongsloi, typically live in small slow-moving streams. Known as Viejita in Colombia, this colourful dwarf cichlid can be found in many streams of the Orinoco River basin, especially the ones between the Sipapo and Cuchivero Rivers. Part of its distribution lies in El Tuparro National Park in Colombia and in the RAMSAR protected wetland of the Bita River. Males have red markings distinguishing them from other Apistogramma species. In the breeding periods, males spend much of their time flashing their fins at each other and displaying brilliant colours. In the sunny sections, the river banks are heavily planted and the light-coloured sand is covered in periphyton. These sunny spots are where you can find many Red Line Dwarf Cichlids gulping up the sand, sifting through it, and spitting out the inedible matter. Females maintain their distance and are usually more inconspicuous, hiding under  leaf litter or between the aquatic plants. Sexually dimorphic, males and females differ in colour and the males are larger than females. Highly sought after by aquarists, this species is found in people’s aquariums around the world. There is no estimated population size of this species, however it faces a number of threats including habitat loss, water pollution and overharvesting. There is a need to understand the population size, distribution and trends to better protect this species.

06/02/23

#152 Common Carp

The Common Carp, Cyprinus carpio, is a widespread freshwater fish species native to eastern Europe and central Asia in the rivers that drain into the Black, Caspian and Aral Seas, but has been introduced into freshwater habitats around the world for food and sport fishing. Common carp found in the Danube River 2000 years ago were kept in specially built ponds by the Romans for consumption. At the same time, it was the first fish species domesticated in China. Both European and Asian subspecies have been farmed and  spread by monks between the 13th and 16th centuries. The Common Carp is one of the major species produced in world aquaculture. Worldwide more than four million tons of common carp are produced annually in aquaculture - making them one of the most economically important fish species. Carps are one of the four species that account for 85% of total inland water catches. Although gregarious (one fish can lay over a million eggs in a year) common carp  populations have declined by 30% in their native range due to river habitat modification including  channelisation which removes in-river habitat and disconnects river from their floodplains, and the installation of dams, which literally cut rivers in half. As Common Carp are naturally potadromous (migrate within rivers to complete their life cycle) and require flood plain  areas to spawn, river modifications are a significant threat. Furthermore, hybridisation with farmed fish is a threat to this species. They are defined as Vulnerable by the IUCN Red List of Threatened Species^TM.

23/01/22

#150 Hawaiian freshwater goby

The O’Opu or Hawaiian freshwater goby, Lentipes concolor, can’t move mountains, but they sure can climb them! More accurately, they can climb the waterfalls of mountain streams of Hawaii, where they are endemic. They use suction disks on their ventral sides formed by the fusion of pelvic fins to climb the wet rocks behind waterfalls, even scaling the 135 m Akaka Falls. Studies show that the O’Opu can reach fast flowing upper stream segments and the elevated suction pressure enhances its ability to successfully capture food. They also need these continuously flowing streams for critical reproductive periods - they are amphidromous, meaning their life cycle is split between freshwater and marine environments, which has enabled them to avoid the inevitable extinction that would befall landlocked fishes in streams destroyed by volcanism or erosion. Adults live in freshwater, where they spawn, and once the larvae hatch, they are washed into the ocean to feed. After metamorphosis, juveniles migrate back to the streams to live the rest of their adult life. Males have black heads and orange tails, while females an olive to brown colour. But both have bright blue eyes. Culturally important, the Hawaiian freshwater goby is food fish for Hawaiians. They were cultivated in aquaculture in the 16th century and aided in the production of the root vegetable, Taro by pruning the leaves and removing pests- a win-win for aquaculture and agriculture. As a narrow-range endemic species, with a unique life cycle, like other pacific island gobies, the Hawaiian freshwater goby is particularly sensitive to anthropogenic changes that may disrupt stream flows, such as channelisation, dams, and water diversions. Assessed as Data Deficient by IUCN Red List, this intriguing species urgently needs more study.

09/01/23

#148 White-tailed Eagle

Appearing in Germany’s coat of arms, the White-tailed Eagle, Haliaeetus albicilla, has one of the largest wingspan of any eagle in the world - up to 2.5m! Living most of the year near large bodies of water, the White-tailed Eagle can be found both on coastlines and inland freshwater areas. Found across Eurasia as far west as Greenland and as far east as Japan, the white-tailed eagle has strongholds in Norway and Russia. Spending most of their day perched on trees, they require forested areas and access to lakes, wetlands, rivers and marshes. Opportunistic feeders, they snatch food from birds and otters but they are also excellent fishers, taking  fish at the surface of the water, where they can reach speeds of up to 70 km/hr. Nests (known as ‘eyries’) are built from mature trees, branches and twigs  and can be up to 2m wide. Females lay 1-3 eggs, and for the first three weeks after hatching, males do all of the hunting. Their offspring leave after 70 days but they are dependent on their parents for 5-6 more weeks. Destruction of wetlands and poisoning from pesticides threaten the white-tailed eagle. Conservation measures such as protecting eyries, providing safe food and re-introduction into specific areas have been put into place. In addition, conservation actions such as adaptive management of wind farms (turning them off during migration periods), preserving perch trees and encouraging use of lead-free ammunition in hunting should be put into place to safeguard this species.

28/11/22

#146 American Paddlefish

Living fossils, American paddlefish, Polyodon spathula, date back to 125 million years ago and are found from the Mississippi basin to New York to Montana and South to the Gulf of Mexico. A species of ray-finned fish closely related to the sturgeon, paddlefish are also harvested for their meat and caviar as an alternative to sturgeon. As filter-feeders, their constant grazing on tiny aquatic organisms helps keep their populations in check with zooplankton as their primary food source. Its snout extends 1/3 of its body length - which is covered with thousands of electroreceptors to locate zooplankton and facilitate migratory behaviour. With undeveloped eyes, they also rely on these electrical receptors for navigation. American paddlefish can grow up to 2 metres long and weigh up to 90kg! Requiring open, free flowing rivers, paddlefish populations have declined due to stream channelisation, levee construction and drainage of bottomlands. Dams prevent paddlefish from being able to move upstream to their spawning territory. The American paddlefish is the only living relative of the Chinese paddlefish, which has recently been declared Extinct by IUCN. Paddlefish populations have declined due to overfishing, pollution, barriers to migration and habitat destruction and are listed as Vulnerable by the IUCN. The American paddlefish is the only member of its family left on Earth. Control of sport and commercial fishing through federal regulations have helped bring back populations and other conservation measures that increase fish passage are being considered.

14/11/22

#144 European River Lamprey

The ancient migratory freshwater species, the European river lamprey, Lampetra fluviatilis, come from the lamprey family which were the first fish to evolve 530 million years ago. European river lampreys are jawless fish, characterised by a funnel-like sucking mouth with teeth - boring into the flesh of other fish and feeding on bodily fluids. Resembling eels, they have a strong flexible cartilage instead of bone and have an average length of 30 cm. Their reproductive cycle is similar to a salmon, hatching in rivers, going to the sea to feed and migrating back into rivers for spawning from autumn to spring. Adults die after spawning -laying up to 25,000 eggs! The larvae spend several years in soft sediment before migrating back to the sea. The construction of dams has reduced their numbers as they are unable to move upstream to their spawning grounds. Worldwide rivers have been fragmented by dams and other hydraulic structures contributing to freshwater biodiversity loss. River lampreys are poor swimmers, thus, not well-adapted to pass barriers. In almost every watershed, lamprey habitats are fragmented. Maintaining connectivity between freshwater spawning and rearing habitats and estuarine/ocean feeding areas is crucial for river lamprey species. In Spain, the river lamprey has been declared officially extinct since 2018. Find out more about dam removal projects in the EU to protect freshwater migratory species like the river lamprey. Allowing free flowing rivers is essential to preventing biodiversity loss in our freshwater ecosystems.

28/10/22

#142 Magdalena Turtle

The prehistoric-looking freshwater turtle known as the Magdalena river turtle or Podocnemis lewyana, is endemic to Colombia, distinct to the Magdalena and Sinu Rivers, but also found in the San Jorge and Cauca River. They diverged from other turtles over 100 million years ago - around the same time humans shared a common ancestor with bats & tigers! Among freshwater turtles they have some of the longest aquatic migratory patterns rarely leaving the water except to bask. Primarily found along the banks of rivers, they are also found in flooded areas connected to rivers where they spend their time basking in the sun. Nesting occurs twice a year during low water level periods on gravel or sand beaches as well as banks and pastures when river levels are low - laying an average of 22 eggs. Adult females are larger than males, weighing up to 8kg and 500mm in length. Locals see these turtles as a source of protein and believe that consuming them provides medicinal benefits such as curing diseases and recovering from pregnancy. Magdalena river turtles are threatened by habitat destruction and pollution, hydrological changes due to dams, traditional consumption and commercial exploitation. The consumption of turtle meat during Lent is deeply rooted in northwestern Colombia’s culture - with over a million turtles thought to be consumed during this period! Populations have declined over 80% in the last 25 years, listed as Critically Endangered by the IUCN. Exploitation of the Magdalena river turtle is prohibited in Colombia, however it is often unenforced.

19/10/22

#140 Pygmy Hippo

The Pygmy hippopotamus, Choeropsis liberiensis, are the smallest species of the hippo family that are reclusive and nocturnal. They are half the size of and weigh ten times less than the Common Hippo. They rely on freshwater to keep their skin moist and their temperature cool. Pygmy hippos are solitary animals - only when a female is accompanied by their young or briefly during breeding are they seen as a pair. They spend roughly 6 hours a day feeding on terrestrial and semi-aquatic plants and spend the day hidden in swamps, wallows and hollows under the banks of streams. Pygmy hippos follow well-defined trails which they mark by vigorously wagging their tail while defecating. Their closest living relatives are whales and dolphins and hippopotamus is derived from the Greek word “river horse”, as it spends its time in rivers and swamps, with  its nose and ears close underwater. Featured in folktales, Pygmy hippos find their way through the forest by carrying a diamond in its mouth to light up its path and they must be caught at night to take the diamond. Deforestation due to palm oil plantations, cultivation and mining and logging, has destroyed their habitat. In addition to habitat loss, increasing hunting intensity has threatened the Pygmy Hippo populations - with only a few thousand left in the wild. They are listed as Endangered by the IUCN. Remaining Pygmy Hippo populations are fully protected in all state range countries and are mainly found in protected areas.

3/10/22

#138 Granular Salamander

Found in subtropical and tropical high-altitude grasslands, freshwater marshes and ponds, the granular salamander, Ambystoma granulosum is a species of mole salamander only found in a small area of central Mexico close to Toluca in Mexico State - 3000 metres above sea level. Mole salamanders diverged from all other salamanders in the Late Jurassic period - over 150 million years ago! These amphibians live around 5 years and breed in marshes, dams and small ponds. They are a metamorphosing species giving them the advantage of reproducing in aquatic environments, swapping out their gills and fins present in their larval stage for eyelids and lungs in their adult stage. Thus, spending the majority of their lifetime on land in grasslands and returning to freshwater to breed yearly and feed. They are threatened by habitat loss, pollution and overcropping due to forest clearance and water extraction by extensive urban and agricultural expansion. Due to low food availability, Granular salamanders experience high mortality rates in their early life stages. Non-native predatory fish are also a major threat to these salamanders. The granular salamander is classified by the IUCN as Endangered as the species has declined over 50% in the last 25 years. Conservation and restoration of the Granular Salamander's habitat is urgently needed.

19/09/2022

#136 Spangled Perch

As Australia’s most widespread native freshwater fish, the Spangled Perch a.k.a  the Spangled Grunter or Jewel Perch, can grow up to 25 cm in length. Leiopotherapon unicolor is naturally found in the freshwater systems in Northern Australia such as the Murchison River, Hunter River, Murray-Darling system as well as the Lake Eyre/Bulloo-Bancania Drainage System. They like swimming in a wide range of waters with little vegetation such as rivers, lakes, dams, billabongs, bore drains, wells and waterholes. This hardy species can survive severe dry periods, found in wet sand after surface water has dried up. It can also tolerate a wide range of temperatures and salinity levels. The spangled perch has a high dispersal rate and the ability to colonise less accessible habitats quickly. Labelled as an extreme dispersal species, this species moves up to 300 km after a flooding event. Females spawn 24,000 to 113,000 eggs allowing their populations to multiply quickly. As opportunistic feeders, the spangled perch have a diverse range of prey including small aquatic insects, fish, molluscs (eg. water snails), crustaceans (eg. shrimps) and plant matter. They are highly adaptable to new environments and can attack a wide range of native aquatic life. Spangled perch can potentially have a highly destructive impact on native species if introduced into waters outside of their range. The Spangled Perch is listed as Least Concern by the IUCN.

05/09/2022

#134 AMAZON LEAFFISH

Leaf or a fish? When swimming in the waters of the Amazon and Orinoco river basins, it might be challenging to determine which one it is - an advantage for this small fish. The Amazon leaffish, Monocirrhus polyacanthus, might seem harmless but is a "wolf in sheep's clothing" or, better yet, a "fish in leaf's clothing". Their remarkably laterally compressed body and orange-yellow to brown colours resemble a floating dead leaf, making it easier to approach unaware prey. The colour patterns' mimicry is outstanding, with several markings that give the impression of dry leaves. But they don't rely only on appearance, putting up a whole show - they actually mimic their environment to facilitate their attack. Amazon leaffish are known to prefer oxbow lakes and streams of blackwater rivers, which are typically dark due to plants' decomposition. Adults live in shallow waters, near fallen leaves on the surface, swimming in a floaty manner towards their prey - fish, crustaceans, and insects. Some scientists say their coloration can adapt to the environment and accentuates during reproductive periods. Sadly, not much more is known about this ludicrous fish. Reproduction has only been observed in aquariums, where it showed an aggressive courtship and male parental care of eggs and larvae, while the female is responsible for driving away intruders. Due to its curious-looking body and rarity, it's exploited by the ornamental fish trade. 

22/08/2022

#132 Goliath frog

Meet the world's largest frog – the Goliath frog, Conraua goliath. Also known as Giant slippery frog, it can reach the size of a small cat – up to 34 cm long and over 3kg. Native to a narrow rainforest region of Cameroon and Equatorial Guinea, it lives in or near clean, large, and fast-flowing rivers and streams. This river giant is omnivorous and opportunistic, feeding both submerged or out of the water. Although scientists previously thought it didn't vocalise, it has an interesting repertoire of calls that includes short whistles, chirping, and even a "sighing deep roar". During breeding, they create nests in streams and small rivers by clearing the area of residues and leaf litter. Recently, scientists found that nesting (likely done by males) includes the heavy lifting of rocks up to 2kg – which might explain why this species evolved such a large body. They observed 3 types of nesting sites to protect developing offspring from river torrents and predators: rock pools, existing washouts, and dug-out depressions in gravel riverbanks. Adults guard the nests filled with 150-300 eggs at night, where tadpoles finish their development into frogs. When feeling threatened, they escape by jumping into the water with a single leap, sometimes skittering across the surface with consecutive hops reaching 3.5m. On land, they seem exhausted after a few jumps, making them easy to capture. Listed as Endangered, they face threats like overhunting for food and the pet trade, habitat and sedimentation loss due to agriculture and hydropower dams, and climate change. Conservation efforts should include keeping their rivers healthy and flowing and working with the local communities to manage harvests sustainably.

08/08/2022

#130 Yellow-spotted river turtle

Native to several South American countries, the Yellow-spotted river turtle, Podocnemis unifilis, is one of the largest freshwater turtles. This species is called charapa or side-necked turtle as it cannot completely insert its head into the shell but bend its neck to one side to attach, leaving a part open. It’s known to inhabit the colossal Amazon River basin, preferring the main channels of large rivers, where it spends most of its time underwater. Yellow-spotted river turtles’ reproductive behaviour is synchronised with seasonal variations in water levels – every year, they congregate for mating and spawning in the dry seasons. To prevent nests from being washed away, they lay their eggs on the dry rivers’ banks and sandy beaches. And hatching mostly coincides with the beginning of the rainy season. They feed on small animals (e.g., crustaceans, insects, molluscs, and fish) and aquatic plants and fruits, being critical seeds disperser. In addition, they have another crucial ecological role as a food source for other animals, including humans. Harvested since pre-colonization times due to its high nutritional value, it is nowadays mainly threatened by unsustainable exploitation, followed by habitat loss and degradation, and climate change. In Ecuador, their populations have declined so severely due to illegal commercialization and overharvesting that they are listed as Critically Endangered. But there is hope - ongoing projects with indigenous communities in the region are looking to restore the Yellow-spotted river turtle populations. Conservation efforts for this and other Amazonian freshwater turtles are likely to be more successful with local community involvement, healthy freshwater habitats, and free-flowing rivers.

26/07/2022

#128 Ship sturgeon

The Ship sturgeon, Acipenser nudiventris, is extinct in the Danube and thus the entire EU territory, despite being protected under the EU Habitats Directive. A sad event that has, since its adoption in 1992, rarely happened before. On a global level, this species' population declined more than 99% in the past three generations (around 120 years). Nowadays, the only confirmed self-sustaining population results from a translocation out of the native range within Kazakhstan. Like the majority (2/3) of sturgeon species, it is listed as Critically Endangered by the IUCN Red List of Threatened Species, indicating its high risk of extinction. Sturgeon are the world's most threatened group species due to historic overexploitation. They face ongoing poaching for illegal trade in wild caviar and meat, hydropower dams blocking migratory routes, unsustainable sand and gravel mining, and habitat loss. As migratory fish, they are good indicators for connected ecosystems - their disappearance highlights freshwater biodiversity's decline and our rivers' degradation. Ship sturgeons used to swim the Black, Aral, and Caspian Sea basins, including large rivers like the Danube. Although there are pure freshwater forms of ship sturgeons, like many sturgeon species, they spend part of their life in salt water and return to rivers to breed. It could reach 2,2m in length, weigh up to 120kg, and live for more than 30 years. The situation for ship sturgeon is bleak. But there's still hope, especially after scientists found six young ship sturgeon in the Rioni River, where a recent expansion of a sturgeon-protected area could boost conservation efforts. WWF's Sturgeon initiative is also working to restore our rivers' health and give sturgeons a fighting chance.  

11/07/2022

#126 Sweet flag

The Sweet flag, Acorus calamus, might not look unique, but it's highly valued across several cultures mainly due to its not­­orious roots. Growing on the margins of shallow nutrient-rich water and streams, canals, fishponds, and lakes, this wetland species is renowned for its long history as a medicinal plant. Mentioned by the father of modern medicine – Hippocrates - it has been used since ancient times as a hallucinogen and an old folk remedy for treating arthritis, diarrhea, hair loss, and other disorders. And there’s more - this semi-aquatic species is multifaceted, used to flavo­­ur pipe tobacco; to purify sewage due to its high tolerance for ammonia and anoxia; in perfumes due to its sweet fragrance, among other. To this day, Sweet flag is studied for its various pharmacological properties, but there are still safety concerns around its toxicity – especially carcinogenicity. Since 1968, this species and its products have been banned as human food or food additive in the USA, and its use is regulated in Europe. Probably due to its versatility – and high pollution tolerance - it became widespread, even generating discussion of its real native range. Most likely native to subtropical Asia, it's non-native throughout much of Europe and southern North America. Although listed as Least Concern by IUCN, there are some local extinctions records. In addition to a growing demand for the drug markets, this species is under threat – like most medicinal plants - from habitat fragmentation, deforestation, and overharvesting. It's time we value our freshwater habitats for all the benefits they safeguard for humans and nature. 

27/06/2022

#124 cuckoo catfish

The cuckoo catfish, Synodontis multipunctatus, is endemic to one of Africa's Great Lakes - Lake Tanganyika. This freshwater fish is named after the cuckoo bird due to their shared (in)famous reproductive strategy - brood parasitism -  that includes finding unaware foster parents for their offspring. The cuckoo catfish is a member of a small group of squeaker catfishes (family Mochokidae), but it is the only one to smuggle its eggs into the care of another species - thick-lipped cichlids. These mouthbrooding cichlids lay their eggs in specially prepared nests, and females collect their eggs immediately after spawning to incubate them in their mouths for about three weeks. Cuckoo catfish exploit the cichlid's parental care by invading their nests at spawning time and creating enough chaos to quickly deposit their cuckoo eggs, which are mistakenly scooped up by the unsuspecting female "surrogate". Male cichlids do respond aggressively to the intruding cuckoo groups, but they get overwhelmed by repeated advances. Although the eggs are not similar - catfish's eggs are different in shape and smaller - cichlid females have to act quickly as their own eggs are at risk of being eaten by the invader. Recent studies show that females co-existing with cuckoo catfish may be able to selectively reject its eggs, but how it's still unknown. Having a cuckoo catfish as a stepsibling can be fatal for baby cichlids - catfish eggs hatch earlier, and they devour the cichlid's embryos over several days. This and other astonishing behaviour in our richly biodiverse freshwaters are still mostly unknown – and we might never get to know them if we don't protect these habitats.

13/06/2022

#122 wATTLED cRANE

Wattled cranes, Bugeranus carunculatus, are Africa's largest and rarest crane. They once ranged from coastal west of Africa to the African horn down to the southern tip of Africa, but nowadays are mostly concentrated in the Okavango delta. Listed as Vulnerable by the IUCN Red List of Threatened Species, their populations have suffered significant declines in southern Africa over the past few decades, especially due to wetlands degradation. This species is the most wetland-dependent of Africa's crane species - relatively intact wetlands like Cuando represent, therefore, an important refuge for these birds. They feed mainly on tubers and rhizomes of aquatic vegetation and large invertebrates and small vertebrates. Generally, they are also not migratory, but those that inhabit seasonal wetlands are irregularly nomadic in response to water availability. They are often seen in pairs – or trios with young birds – where the male tends to be larger than the female. They are usually silent and territorial when in pairs, but they can be seen in larger "floater" flocks.

30/05/2022

#121 Smooth-coated Otter

The Smooth-coated otter, Lutrogale perspicillata, is the largest otter species in Asia. Found in South Asia and Southeast Asia’s slow-flowing waters typical of rice paddies and floodplains, and large rivers in some regions, they have a large distribution that is slowly and steadily decreasing. It was once widespread from the Middle East to southeast Asia, but its biggest asset became a problem – its short, smooth velvety fur is attractive to the illegal wildlife trade. The smooth two-layered fur - warm chocolate brown on the back and soft grey on the stomach - helps keep the underfur dry underwater to retain body heat. Mainly nocturnal, this species forms large, vocal family groups that prey together on fish, shrimps, frogs, crabs, insects, and birds. They catch prey with their sharp claws on their webbed paws, which boost their swimming abilities together with their paddle-like flat tail. Listed as Vulnerable by the IUCN, habitat degradation and loss due to increasing anthropogenic pressure on wetlands and waterways threaten these otters. They need thick riverside vegetation to hide, dig dens and raise cubs. In addition, illegal trapping for the fur trade has recently taken a heavy toll in many of their range countries, and law enforcement is lacking. They are also wanted as pets and for traditional medicine. 

09/05/2022

#119 Indus valley bullfrog

Indus Valley bullfrog, Holobatrachus tigerinus, a.k.a Indian bullfrog, is one of the largest frogs on the Pakistani plains. Found in the freshwater wetlands - natural and artificial – of Pakistan’s Indus River basin, this frog can hibernate during winter and drought by burrowing itself in soil. It is also common in paddy fields and moist riparian areas of Afghanistan, Bangladesh, Bhutan, India, Myanmar, and Nepal. Sadly, it has been introduced to Madagascar and Maldives, which can have a negative impact on the invaded ecosystem’s integrity. Indus Valley bullfrogs are voracious feeders - anything that is moving is game, bounced upon, and swallowed. If needed, they use their anterior limbs to thrust larger food into their mouth, including mice, young frogs, juvenile snakes, and small birds. They don’t tend to stay in water for long – when danger approaches, they plunge into deep water using their almost fully webbed feet and stay underwater for a few minutes. If in clear pools,they hide under bottom gravel. With the beginning of the monsoon, a large number may be seen all over the fields around temporary water pools. And many of them will be easier to spot due to their recently acquired lemon-yellow colour. Yes, this species can change colours – during the breeding season, males turn yellow and their deep blue vocal sacs more prominent, while females remain dull and drab-coloured. Sitting close to each other in shallow water, calling males repeat their powerful nasal call several times, now and then jumping over each other. Lurching around, females are grabbed by the males when in range, and after some fighting with the neighbours, the pair somehow moves to a quieter place to lay the eggs. This species is listed as  Least Concern by IUCN Red List. 

25/04/2022

#117 Waterbuck

The waterbuck, Kobus ellipsiprymnus, is a highly water-dependent mammal. It is usually only found “at or near water” due to its high susceptibility to dehydration and overheating relative to other African bovids. This medium-sized (150–300 kg) antelope occurs widely throughout Africa, in habitats like lakeshores, riverine woodlands, and open grasslands, including the dazzling Hluhluwe-Imfolozi Park in South Africa, where the life-giving Imfolozi River boasts rich biodiversity. Waterbucks have a reputation of being smelly due to a musky oil secreted by glands in their skin, which forms a waterproof layer around the hair, protecting their skin when they enter the water. They have been known to dash into water to evade predators like lions and leopards. They also exhibit strong territorial behavior, where males defend areas close to water with abundant and high-quality forage. Although listed as Least Concern by the IUCN Red List, this species’ populations are declining due to hunting. 

11/04/2022

#115 Ganges river dolphin

The Ganges river dolphin, Platanista gangetica gangetica, is one of the most ancient dolphin species still alive, being considered a living fossil. It is known as the "Tiger of the Ganges" due to its role as a top predator and an ecosystem indicator species – like a tiger is in its habitat. This species has many common names, which in local languages are reminiscent of the dolphin's breathing noise like "susu". But they are generally shy towards humans and most often found alone. With extremely poor eyesight, they rely almost entirely on echolocation to navigate and locate their prey, usually fish and crustaceans. They are found only in the river systems of the Ganges-Brahmaputra-Meghna, and nearby Karnaphuli-Sangu River, in Bangladesh, India, and Nepal. Like the Indus river dolphins, they have a particular side swimming behaviour that helps them navigate shallow waters. In the past, during the monsoon season, these dolphins would move upstream into smaller rivers and then back downstream to larger channels in the low water winter. But nowadays, dams and barrages restrict their movement. They are under great threat due to proposed and ongoing large infrastructure projects, which can also destroy their habitat and decline river flows. Listed as Endangered by the IUCN Red List of Threatened Species, they are also at risk because of fisheries bycatch and pollution. But there's hope for the Ganges river dolphin. They are legally protected in all the countries in which it lives. And WWF's initiatives like River Dolphin Rivers tackles the systemic threats – unsustainable fisheries, hydropower and infrastructure, and pollution –, also protecting their habitats for the benefit of people and nature (Learn more about this species with this video). 

28/03/2022

#113 New Guinea Crocodile

The New Guinea crocodile, Crocodylus novaeguineae, is a medium-sized crocodile that prefers swimming in New Guinea island's vast freshwater systems like rivers, swamps, and marshes. Restricted to the island of Papua New Guinea and Papua including  Pulau Kimaam , this species can grow up to 3 m for females and 3.5 m for males, especially in the Sepik River, where larger animals can be found. The Sepik is one of the largest rivers in the Asia-Pacific region, harbouring some of the world's largest freshwater and saltwater crocodile populations. Sepik's crocodile species, including the New Guinea crocodile, have cultural significance to the communities living across the river - they pay them tribute every year with a three-day Crocodile Festival. Inspiring cultural traditions, beliefs, and legends, this ancient animal symbolises strength, power, and manhood. Man and crocodile share a special bond in Sepik culture, literally embodied by men proudly wearing scars that resemble the back of a crocodile. It's during the rite of passage of skin-cutting initiations that they cut these scars into their skin from shoulder to hip. Listed as Least Concern by the IUCN, this species' populations benefit from the vast areas of wetland habitats and low human population density in Papua New Guinea and Papua. Management programs regulate exploitation while providing equitable economic incentives to indigenous landowners. There are threats from introduced fish (Pacu, Piaractus brachtpomus) and mining which could increase in future. Plans to develop the largest mines in the country on one of Sepik's major tributaries threaten the future of the river basin, its people, and nature. But the people of the Sepik are fighting to save their river and all it offers them.

14/03/2022

#111 Zambezi shark

The Zambezi shark, Carcharhinus leucas, a.k.a. bull shark, is one of the few shark species known to travel long distances into rivers systems and remain there for long periods. Famous for this ability, it's also named after the mighty Zambezi, where it reached up to 1120km away from the ocean. But they also swim other rivers – and even hypersaline lakes - worldwide, with a record of 5080km away from the ocean in the Amazon/Ucayali River. But why and how do they do that? They rely on estuaries and rivers as nursery habitats, where pregnant females give birth and juveniles can remain for five years. They are a fully euryhaline species, able to move easily between marine and freshwater habitats thanks to osmoregulation - their body acclimates to changes in salinity via independent regulation of sodium/chloride and urea levels. This adaptation favours their broad range, including coastlines of all three big oceans (Atlantic, Indian, Pacific) in both hemispheres, with evidence of their presence in 415 fresh and brackish water localities. Reaching up to 4m in length, they are named Bull sharks due to their short, blunt snout and tendency to head-butt their prey before attacking. They are generalist predators  and eat almost anything they see - fish, including other sharks, and also dolphins, birds, turtles and invertebrates. This species is listed as Vulnerable by the IUCN due to fishing as a target for meat and fins and a bycatch. In addition, their habitat preference means they are also threatened, especially juveniles, by habitat loss and degradation, including damming, pollution, and climate change. In the Zambezi River, the Cabora Bassa Dam wall and the Kariba Dam currently prevent this species' migration to the river's upper reaches. 

28/02/2022

#109 Yangtze Giant softshell turtle

The Yangtze Giant softshell turtle, Rafetus swinhoei, is one of the world’s rarest reptiles. Reaching around 120 kg in size, this enormous freshwater turtle is a bit strange-looking with its long flat carapace, soft body, pig nose, and a long neck capable of “periscoping” like an otter. Due to its rarity, we know very little about them - adults seem to be omnivorous, fairly sedentary and reach up to 100 years. They are worshipped in some areas - Vietnamese mythology says this enormous turtle is the living representative of the Great Turtle God, Kim Qui. But not even its god-like status could save them - they are one of the most severely threatened species on Earth. Listed as Critically Endangered, only four surviving individuals are known - two of which are in captivity, and none have reproduced successfully recently. Decades of dam-building likely fragmented populations, getting several turtles stranded in lakes and reservoirs. This species is also at the brink of extinction due to exploitation of adults and eggs for (subsistence) consumption and targeted capture attempts in recent years, habitat loss for agriculture like rice paddies, pollution of wetlands and riparian habitats, and sand mining. Historically, this species inhabited the Red River of Yunnan and Viet Nam and the lower Yangtze River floodplain. Nowadays, its area of occupancy is less than 10km2 after a population reduction of over 99% over the last two generations. But we can’t give up on these divine turtles. Captive breeding efforts continue, and field surveys to locate additional animals in the wild. The Asian Turtle Program works with villagers and stakeholders to protect and monitor the two known wild individuals in Viet Nam. And WWF’s Emergency Recovery Plan outlines how to reverse the rapid decline of their critical freshwater habitats. 

14/02/2022

#107 Siamese tiger perch

The dazzling stripes of the Siamese tiger perch, Datnioides pulcher, used to brighten up the rivers of the Indo-China area, from the Mae Klong and Chao Phraya basins to the middle and lower reaches of the mighty Mekong. Extirpated from Thailand in the 1990s, this Critically Endangered fish is now rare in Cambodia, Vietnam, and Lao PDR. The attractive vertical yellow and black patterns are the main reason for its demise - researchers estimate that its global population has declined by more than 90% over the past 20 years after high levels of exploitation for the international aquarium trade. Although rarely seen, it is still fished for this purpose when found. In addition to overfishing, the Siamese tiger perch faces major threats from habitat destruction and degradation from dams and infrastructure in tributaries (small dams, weirs, locks), blocking paths between the main river and tributaries. And this tiger perch does like to swim these waterways, including larger lakes connected to rivers, preferring habitats with submerged woods and rocky crevices. Growing up to 40cm, this tiger perch feeds on fishes and shrimps and was once a popular food fish in Thailand and Cambodia. Artificial breeding has been attempted since the 1990s in Thailand to try bending the curve of its populations, but without success. The species is also protected – it is illegal to catch or possess it. But this law is written under its previous scientific name (Coius pulcher), creating issues when implementing it. And there are many other species on the brink of extinction, and many we don't even know exist. The Mekong River Basin is home to astonishing biodiversity, and hundreds of new species are still discovered every year – WWF's report shows over 200 species identified in the Greater Mekong area just in 2020. The Siamese tiger perch is just one of 95 fishes. The Asian Species Action Partnership (ASAP!) , which is a platform with over 200 organizations including WWF, aims to end species extinction in Southeast Asia.

31/01/2022

#105 Yacare caiman

The Caiman yacare is an iconic freshwater reptile of South America. They swim the freshwater rivers and wetlands of Paraguay, Northern Argentina, Southern Brazil and Bolivia, being especially well-known in the world’s largest tropical wetland - the Pantanal. They are even named after their mesmerizing habitat in Brazil, being called “Jacaré-do-pantanal” (Pantanal’s yacare). And they also go by a curious nickname, “Jacaré-piranha” (Yacare-piranha), since even with their mouth closed, they show many teeth. They feed mainly on fish and aquatic invertebrates, but their diet also includes birds, reptiles, and mammals. When fishing, this species  uses a tactic similar to other caimans called collective fishing, where 2 to 15 animals line up in a channel against the current and grab passing fish without individual aggression. It is a medium-sized crocodilian, with male Yacares reaching up to 3m in length and females 2,5m. The mound-nester females place the nests close to canals and rivers, guarding them – behaviour apparently influenced by human hunting pressure – and defending their offspring aggressively when juveniles hatch. Even though abundant, widely distributed, and listed as Least Concern, this species is subject to ranching wild harvest, and its habitat faces many threats. The river that feeds the Pantanal, the Paraguay River, is threatened by hydropower plants. The region also faces agriculture expansion, engineering work for navigation, and climate change. 

17/01/2022

#103 Red lechwe

The Red lechwe, Kobus leche leche, is a mammal associated with wetlands, preferring the shallow water margins of floodplains and swamps and occasionally swimming across deep-water areas. It is the most widespread subspecies of the Southern Lechwe (Kobus leche) - commonly seen grazing the wetlands of south-central Africa, including in the magnificent Okavango Delta in Botswana and the Linyanti swamps of the Caprivi Strip, Namibia. Southern Lechwes are medium-sized antelopes that have adapted to their wet environment by having distinctly elongated hooves. Red lechwes feed on the lush green aquatic and semi-aquatic grasses, being particularly dependent on this environment and, therefore, an important indicator species. Lechwes' males (a.k.a. rams) are the only ones to carry lyrate-shaped horns. They are territorial, and males that fail to establish territories congregate in bachelor herds. Females (a.k.a ewes) form breeding herds with their offspring, moving freely between ram territories – males compete for mating favours only when receptive ewes are within their domains. Breeding is not strictly seasonal, especially not amongst Red Lechwe's Botswana populations. When about to give birth to single lambs, pregnant females leave the herd to find cover on clumps of bushes, where they keep their offspring hidden for two to three weeks. Sadly, due to poaching, expansion of agriculture and livestock grazing, changes in water management regimes, drought, and encroachment by alien plant species, The IUCN lists the Southern Lechwe as Near-Threatened, and there is also evidence of Red Lechwe populations' decline over the past years.

03/01/2022

#101 TUCUXI

Tucuxi, Sotalia fluviatilis, is the guardian of the river and a symbol of good luck, according to the local communities of the Amazon River basin, including the Tapajós river. This positive image is thanks to its ability to avoid rocky and shallow waters, guiding boats to safe river sections. The Tucuxi swims in Brazil, Colombia, Ecuador, and Peru. This species overlaps in range with the Amazon river dolphin, but it is easy to distinguish them, as it is smaller, tends to be in larger groups, and swims faster. This is the only river dolphin that jumps like marine dolphins, and it is perceived as vivacious and sociable. They rely heavily on echolocation to communicate, navigate, and find food in the dark and sometimes turbid waters like other dolphin species. Scientists believe that they prey on various fish species and crustaceans, but studies are scarce. Sadly, they are listed as Endangered due to death caused by fishing gear, habitat degradation due to dams, pollution from gold mining, navigation, and sand and gravel mining. WWF’s River Dolphin Rivers initiative focuses on eliminating the use of gillnets – curtains of fishing nets that hang in the water – and preventing new dams to stop their population decline and enable them to recover. The Tucuxi is also included in international legislation such as the Convention on Migratory Species (CMS). Recently, conservation action plans were put in place for the species at both national and continent-wide levels. Learn more about this river dolphin here.

29/11/2021

#99 Malatgan River Caecilian

The Malatgan River Caecilian, Ichthyophis weberi, was a “lost” species up to 2015. It was not seen for about 60 years until researchers found one near the Malatgan River in Palawan, Philippines. Caecilians are part of a group of legless amphibians, most species spending the best part of their lives below ground or plying the waters of shallow streams. Malatgan River Caecilians are no different – they live in riverine habitats, usually river banks in lowland forest and adults are likely to be subterranean. Unsurprisingly, much remains unknown about this species, including its breeding strategy and the low number of recordings, which may be explained by its natural rarity or secretive ground-digging behavior. The IUCN Red List of Threatened Species lists them as Endangered due to habitat destruction, especially lowland forests, which results in the degradation of streams and creeks. But there are reasons to be optimistic thanks to the efforts of Fins and Leaves, the NGO that led the expedition for the rediscovery of Malatgan River Caecilians. They also led the work to declare the Cleopatra’s Needle Mountain Range, where this species is found, as a protected area.
 

 

15/11/2021

#97 Chindongo demasoni

The colourful Chindongo demasoni is a small fish endemic to Lake Malawi in Tanzania. This eight centimetres cichlid occurs at the lake’s small reefs, with a population also thought to be small. IUCN assesses their population as Vulnerable due to threats from sedimentation and over-collection for the ornamental trade. The striking fish inhabits intermediate, stony and rocky substrates in shallow waters, feeding on a mixture of algae, cyanobacteria, heterotrophic microbes, and detritus. Unlike many Malawian fish species males and females have the same colour: a bright light blue body with dark blue/purple to almost black vertical stripes. They differ slightly in terms of length, where the male is a bit bigger than the female. Like most Malawian cichlids, they are mouthbrooders – females will keep the fertilized eggs inside their mouth for about 21 days until their fry is ready for the world.

01/11/2021

#95 TADPOLE SHRIMP

The tadpole shrimp, Triops longicaudatus, is a widely distributed living fossil. Although not really a shrimp, this species is part of a diverse and small group of ecologically important, largely freshwater primitive crustaceans. The broad shield-like double carapace covers most of their body, and when they swim, they present a unique outlook due to the arrangement and the movement of little “limbs” called phyllopods. These phyllopods beat sequentially and fast, forming spectacular wave-fronts. They also use phyllopods to feed, which moves the prey towards their mouth. They live on the bottom of temporary pools, ponds, and shallow lakes, feeding on all available food sources - living or dead organisms – to reach maturity and lay their eggs as soon as possible. Their eggs might be one of the reasons why the tadpole shrimp has been around for so long – they are almost impossible to kill and are even able to survive for decades. If environmental conditions are not favourable (e.g., extreme temperatures), the female will modify the fertilized eggs or “cysts/resting eggs'' to enter a state of dormancy, and they will only hatch once conditions improve. Due to the reduction in the number and quality of temporary wetlands, several species of tadpoles have been assessed as endangered by IUCN Red List of Species. 

18/10

#93 Aquatic anole

This lizard is one of the most notable species in the animal kingdom, as it has mastered the art of “scuba-diving”. The Aquatic anole, Anolis aquaticus, is part of a remarkable group of lizards – the Anoles (genus Anolis), which have diversified in many ways to take advantage of their environment. Found along stream margins in the lowlands and premontane slopes of Costa Rica and Panama, Anolis aquaticus is a mid-sized semi-aquatic lizard recently made famous for spending up to 16 minutes underwater! Researcher Dr. Lindsey Swierk hypothesized that they adapted to evade predators by using a bubble attached to their snouts to recycle oxygen – like a scuba tank. Many other lizard species are known to escape from threats via water: some swim, either remaining at the surface or diving, while others use foot-slapping to run over water, and some even combine the two. Aquatic anoles use a combination of surface swimming and diving, jumping into (generally) small and slow-moving streams from the banks and boulders of their riparian habitats to which they are restricted. They swim for a short distance (up to a few meters) or are carried downstream by the current while “rebreathing” exhaled air that gets trapped between their skin and the surrounding water. 

04/10/2021

#91 Siamese fighting fish

The Siamese fighting fish, Betta splendens, is unique not only in its beautiful colours but also in its fascinating reproductive behaviour. Before pursuing the female, the male Siamese fighting fish meticulously prepare a nest of bubbles that will provide oxygen for its developing future offspring. After chasing and finding their female mate, males fertilise the eggs, and the pair place each egg carefully into the nest. But the males’ job is not done yet – they will guard the nest until the eggs hatch, a few days later. Endemic to Thailand, this species inhabits intact marshlands in shallow zones from the Mae Khlong to Chao Phraya basins. Sadly, Siamese fighting fish populations are decreasing, mainly due to habitat degradation. Their freshwater habitats have been converted into intensive farmland and urban areas or are polluted, especially in central Thailand, which is its centre of population. They are also threatened by genetic erosion from escaped farmed stock into wild habitats. This species is very popular in the aquarium trade, being bred in many domestic variations for national and international markets.

20/09/2021

#89 Eurasian water shrew

The Eurasian water shrew, Neomys fodiens, is one of the few venomous mammals left in the world. With its venomous saliva, this semi-aquatic species paralyses its prey. It hunts on land or in water, where they dive in and swim at a fast pace, searching for invertebrates like crustaceans and insects. Occasionally they are known to take small fish and amphibians. Even though Eurasian water shrews don’t have webbed feet, scientists believe that the stiff hairs on their back feet and tail aid swimming by propelling them in the water. They also have a thick and water-repellent fur, which protects against the cold and wet. Biologists have recently uncovered the genetic secrets of the diving behaviour of this species and its order, Eulipotyphla, which means truly fat and blind. They are the most aquatic of all European shrews, living in small holes  in the banks of their watery habitats. These include many wetland habitats, including lakes, rivers, streams, marshes, and bogs. This species is solitary and highly territorial, with males only leaving their turf to search for females in the breeding season. They extend from the British Islands eastwards to Lake Baikal, Yenisei River (Russia), Tien Shan (China), and northwest Mongolia. They are also found in the Mediterranean, from northern Spain to Bulgaria. Although generally abundant and assessed as Least Concern, there are records of local population declines most likely due to wetlands loss and degradation (e.g., drainage, pollution).

23/08/2021

#85 Hump-backed mahseer

The Hump-backed mahseer, Tor remadevii, is the largest of the iconic mahseer species. Endemic to the River Cauvery, this species is the most widely recognised fish in India and is worshipped as a god by the Mullukuruma people of Wayanad, Kerala. But its mythical status goes beyond India’s borders - it has lured anglers from all over the world since the 1970s. Anglers have had an important role in conserving this freshwater mega-fish. The income generated from international anglers visiting the Cauvery supported the transformation of former poachers into angling guides and river guardians, motivating them to protect the mahseer and their lucrative new income stream. Also, scientists analysed the detailed catch-log books kept by angling camps in 2015 and found that the mahseer population was in decline. This evidence supported the formal recognition of the Hump-backed mahseer as a separate species and its classification as Critically Endangered by the IUCN Red List of Threatened Species. It became possible to assess that the Hump-backed mahseer was reduced by more than 90% over three generations, mainly due to the introduction of non-native species, habitat degradation, and illegal and unsustainable exploitation. Anglers and other local and international stakeholders play a crucial role in bringing the species back from the brink of extinction. The Mahseer Trust released a cartoon story to share some insights from their long-running research and interviews with the indigenous people of Wayanad, whose rich cultural heritage respects and helps to protect the priceless Hump-backed mahseer. 

04/09/2021

#87 AMAZON KINGFISHER

Contrary to what its name might suggest, the beautiful Amazon kingfisher, Chloroceryle amazona, can be found from Mexico to Argentina. Although described in the Amazon, this species has been abundant in many regions of South America, having cultural significance and even becoming the bird-symbol of Florianópolis, a city in the South of Brazil. This petite bird species is resident (non-migratory) and inhabits rivers and the edges of ponds and lakes, favouring smaller and slow-flowing rivers and creeks. Amazon kingfishers are generally found in pairs or singly, especially when fishing. Their strong beak is specially adapted to capture fish, and they are often seen perched on a branch or rock close to water before plunging headfirst after their favourite prey. They breed by streams and build holes in ravines near the water bodies, using them for nesting. Males attract females by offering them food, and the pair can stay together for years. They look very different from each other – males have white underparts apart from a broad chestnut breast band and some green streaks on the flanks, while females’ plumages are less bright and with white underparts and green patches on the side of the chest and green flank streaks. Their population is vast but with a decreasing current trend, being listed as Least Concern by the IUCN List of Threatened Species.

09/08/2021

#83 Rogue mushroom

This fungi species seems to have gone “rogue" – it's the only reported aquatic gilled mushroom! More than 600 known freshwater fungi are known, but they are usually microscopic and do not produce visible fruiting bodies like mushrooms. It is very rare to find members of the Basidiomycetes that can grow underwater, especially submerged and truly gilled mushrooms. During a family picnic in 2005, hydrologist and professor Robert Coffan from Southern Oregon University discovered this intriguing species in the Rogue River in Oregon. Prof. Coffan reached out to colleagues (mycologists), and five years later, the Rogue mushroom was described as a new species as researchers confirmed this species' unique DNA fingerprint. But there's still much to learn. P.aquatica breaks down dead organic plant matter and usually grows on wood as a substrate. But scientists are still investigating how this species breathes and releases its spores to reproduce, as all the other gilled mushrooms do it through the air. One of the hypotheses is that in addition to buoyantly stabilizing P.aquatica underwater, the large gas bubble trapped under the mushroom cap provides a chamber wherein spores eject. But then spores could flow downstream to the ocean, leading to another hypothesis that aquatic insects could be dispersing them as their larvae have been observed grazing and filter-feeding on the mushroom. The bubble could also function as a type of external lung, facilitating oxygen exchange. The Rogue river is notoriously highly oxygenated, which may limit the mushrooms’ distribution; so far, only two populations have been found.

26/07/2021

#81 Large red damsel

The Large red damsel, Pyrrhosoma nymphula, is one of the most common damselflies in Europe’s wetlands. But be aware, they are very similar to another species: the Small red damselfly, which is less red. Large red damsel males are bright red with a black thorax, but females can be almost entirely black. Most likely, you will see the active and robust Large red damsel flying over or near slow-flowing and standing waters. However, in eastern and northern Europe, where it is less common, it mostly reproduces at running waters. They also have smaller numbers in north Morocco, northern Tunisia, and the mountains of Southwest Asia. They like breeding mainly in a wide variety of wetlands, from acidic bog pools to brackish ditches, especially sheltered waters with abundant aquatic plants. Their aquatic nymphs (or naiads) have elongated abdomens that terminate in three leaf-shaped tracheal gills. These fascinating gills can absorb dissolved oxygen from water and function as fins during the undulating swim of the larvae. Damselfly nymphs tend to stay for one year underwater. When it’s time to emerge, they crawl onto the shore or cling to an emergent aquatic plant and shed into adults. Shed skins are a common sight on waterside vegetation, especially for Large red damselflies, as most adults emerge from the pond at the same time over a short period in the spring. 

12/07/2021

#79 Maripano piranha

Pristobrycon careospinus is a rare piranha locally called Maripano by the Piaroa ethnic group in Venezuela. The rare photo - actually the first live pictures of this species! - was taken by the Photographer Ivan Mokolji, who explains how he managed such a difficult task on this great article. Found in the Atabapo river in the Orinoco basin, this species is part of the Serrasalmidae fish family - piranhas and pacus. Serralmids are keystone ecological taxa - some species are top riverine predators and/or primary seed dispersers in the flooded forest. Piranhas are notoriously famous for their ferocity, mainly due to feeding on corpses and nipping bathers to defend their nests. While piranhas are indeed generally carnivorous, some species like the Maripano are facultative frugivores: they can eat both other animals (e.g., insects and fish) as well as fruits, seeds, and leaves. Despite their keystone status and commercial significance throughout South America's Amazon, the ecology of piranhas and pacus are poorly understood. Pristobrycon careospinus is known from only the original description with a single specimen captured in 1974. Hence, records such as Mokolji's are essential for freshwater biodiversity assessments and conservation.

28/06/2021

#77 Freshwater pufferfish

Pufferfishes are also in freshwaters – meet the Freshwater pufferfish, Tetraodon mbu. Freshwater pufferfishes inhabit large rivers and lakes, feeding mainly on molluscs and insects. This species is widely distributed in the Congo river basin, besides living in the delta and lower Malagarasi River in Tanzania. In this restricted range, it is listed as Vulnerable by the IUCN Red List of Threatened Species due to increased agriculture and land-use change. Overall, their population trend is unknown, and conservation efforts would benefit from research and monitoring of the Congo basin. Pufferfishes present many fascinating features, one of the best known being their defensive behaviour against predation in which they inflate their bodies, looking like a colourful floating balloon. By swallowing water, they can reach a volume almost four times their average size. They are also among the most poisonous fish in the world – they have potent neurotoxins, which can cause fatal human intoxication. Some freshwater puffer species present a high level of toxins on their skin, but further studies on the Tetraodon mbu are necessary to give us a clearer picture. 

14/06/2021

#75 Dumbéa River pipefish

Freshwaters also have beautiful colourful pipefishes - meet the Dumbéa river pipefish, Microphis cruentus, endemic to New Caledonia. Closely related to seahorses, freshwater pipefishes mainly inhabit tropical and temperate seas. But there are a few species in the Indo-Australian Archipelago restricted to freshwater, such as the Dumbéa river pipefish. Known from the lower reaches of the Dumbéa River, this species likely feeds on small benthic and planktonic animals like insect larvae and crustaceans. Similar to other pipefishes, Dumbéa females deposit their eggs underneath the male's trunk or tail. And the male is the one that does the work of incubating them for several weeks in either partly or wholly concealed pouch. Not much is known about this species, being listed as Data Deficient by the IUCN Red List of Threatened Species. Recently, Shoal - an organisation dedicated to conserving freshwater species – launched the Search for the Lost Fishes campaign. They considered adding this species to the Top 10 Most Wanted species, as it hadn't been seen for a decade - or so they thought. Glady, thanks to the naturalist Damien Brouste, who recorded the Dumbéa on the citizen science and naturalist platform iNaturalist, Shoal discovered that this species wasn't a lost fish. 

31/05/2021

#73 Moss animal

Cristatella mucedo is a small freshwater invertebrate which is part of Bryozoa phylum, sometimes known as moss animals. C. mucedo has a wide range and is distributed across America, England, Norway, Poland, New Zealand, and likely many other places. As they are not as well studied as other species and we still have lots to learn about these bryozoans. This species likes stiller waters such as lakes, ponds, and slow flowing streams and rivers and is generally found up to 2m in depth. It grows on submerged substrates as colonies of genetically identical individuals called zooids. Each zooid is about 2 mm long and has a horseshoe crown with 80-100 ciliated tentacles, which it uses to capture and filter organic particles. Zooids form clear, soft, gelatinous colonies resembling a caterpillar. Most bryozoan colonies are strictly sessile, but C. mucedo is somewhat mobile – it moves a few cm/day by sliding, and scientists presume that a thin fluid secreted by its cells helps them glide. But it may be that muscles in the colony bottom wall also play a role. They are primarily asexual and reproduce via small encapsulated structures called statoblasts, which potentially form new colonies. Water currents, wind, and animals like fish and aquatic birds disperse the statoblasts. This tiny invertebrate generally does not like polluted waters, and its presence indicates good water quality.

17/05/2021

#71 Lister's river snail

The charming Viviparus contectus is part of a family of river snails – the Viviparidae. The family name is due to their ovoviviparity: they bear live young - their offspring hatch from the eggs inside the female's body. As a gilled snail, Lister's river snail can breathe underwater - it allows water to enter the shell and go through its gills to obtain dissolved oxygen. Due to this ability, they are also able to filter water like mussels. This trait is important in polluted waters, where increasing temperatures combined with rising nutrient inputs tend to intensify eutrophication symptoms. V. contectus feeds on organic particles and microbes and lives in large slow-flowing rivers, large drainage ditches, fenland dykes, ditches on grazing marshes, and large ponds and lakes. This species is widespread in many countries in the Palearctic region, but there are considerable gaps in the taxonomy. They can host different groups of parasites, including those of medical importance. This species has been used as a traditional medicine in Korea and China for liver diseases and alcohol poisoning. The latter country also uses it as a food supplement since it contains high amounts of protein, essential amino acids, taurine, calcium, iron, and zinc. This freshwater snail is also part of the aquarium trade, but the main known threats are pollution and habitat loss. They are listed as Least Concern by the IUCN Red List of Threatened Species and with a decreasing population trend. 

04/05/2021

#69 fishing cat

Not all cats dislike water – the Fishing cat, Prionailurus viverrinus, is strongly associated with wetlands and, as its name implies, it often enters the water to fish. Their exceptional dietary choice among felids suggests even some morphological adaptations such as semi-retractile claws that can grip slippery aquatic prey and a double-coated fur, which prevents the body from getting wet. But this nocturnal and elusive cat also preys on frogs, crustaceans, snakes, birds, and scavenges on carcasses of larger animals. About twice the size of a typical house cat, this species preferred habitat is wetlands, which destruction and degradation have led to its populations' decline. Listed as Vulnerable by the IUCN Red List of Threatened Species due to threats such habitat loss (from urban encroachment) and other threats such as wetland drainage for agriculture, pollution, and logging, which has lead to the eradication of Fishing cats from much of their previous range across South and Southeast Asia. Since 1970, the world has lost approximately 87% of its wetlands, and those remaining are disappearing three times faster than forests. A healthy population of fishing cats, and their prey, can only be sustained in a healthy environment. Learn more with this great read.
 

19/04/2021

#67 Afia Birago's puddle Frog

The Afia Birago's puddle Frog, Phrynobatrachus afiabirago, is named after the mother of Ghana's first formally trained herpetologist, Dr. Caleb Ofori-Boateng. Dr. Caleb discovered the endemic puddle frog in the Atewa Forest's swampy habitats in Ghana – a unique area of mountain forest-like vegetation in West Africa. This puddle frog likes large forest ponds and swamps, presumably breeding in the water. Its population inhabits only two known sites, and it's likely to be decreasing due to the ongoing decline of the extent and quality of their habitats. In 2016, a wave of bushfires destroyed most of the forest habitat close to one of the frog's ponds. Listed as Critically Endangered by the IUCN Red List of Threatened Species in 2019, Afia Birago's puddle frogs face threats such as ongoing illegal logging, artisanal mining, and farming. Scientists estimate that 80% of the already small population will disappear in the next ten years if bauxite mining plans in the Atewa Forest Reserve move forward. Dr. Caleb and many environmental Civil Society Organizations argue that mining in that region would be catastrophic to biodiversity and human health as Atewa is the water source for over five million people. Finding the endemic frog secured Atewa Forest Reserve's designation as an Alliance for Zero Extinction site, restricting mining as an activity in this habitat which is already a Key Biodiversity Area. Also, together with Synchronicity Earth, Dr. Caleb started an amphibian monitoring programme in the region. 

05/04/2021

#65 Splashing tetra

The Splashing tetra, Copella arnoldi, is an extraordinary fish species – it lays its eggs on land! At the water's surface, females and males lineup side by side and jump together out of the water to spawn. Females lay their eggs on hanging leaves, and males fertilize them immediately. The male is then tasked with keeping the eggs moist by splashing them with its tail for around three days until they hatch and fry fall into the water. The unique breeding behaviour and parental care can be seen in the Orinoco and Amazon rivers in South America - this species native range. They have high commercial importance as ornamental fish in the region. According to the Brazilian Red List of Threatened Species, the Splashing tetra is listed as Least Concerned. However, the last assessment was made in 2014, and their freshwater habitat is under pressure mainly from hydropower dams. 

22/03/2021

#63 Singapore freshwater crab

Singapore freshwater crabs, Johora singaporensis, are smaller than the size of a thumb, growing 2 to 3 cm. Endemic to Singapore’s freshwater habitats, this species hides under rocks along river edges and inside clumps of leaves and detritus. They feed on plant detritus and oligochaete worms present in the soft stream's mud. Listed as Critically Endangered by the IUCN Red List of Threatened Species, this species is sadly among the world's most threatened species. They prefer relatively clean and fast-flowing streams in the highlands, which are at higher risk due to habitat loss and habitat acidification. Conservation efforts include measures to increase this species' wild populations, led by the Freshwater Crab Working Group in Singapore. NParks (National Parks Board) of Singapore has successfully hatched more than 150 crablets in captivity and has begun to release these captive-born individuals into the wild. In 2018, in partnership with Singapore’s National Parks Board (NParks), WWF highlighted 10 threatened species in Singapore currently under active conservation, including the tiny Singapore freshwater crab.

08/03/2021

#61 Freshwater sponge

Spongilla lacustris is one of the 248 known freshwater sponge species occurring globally. S. lacustris is the most common and widespread freshwater sponge species and the most abundant in Central Europe. It lives in rivers and preferably lakes, often growing attached under rocks or logs. Its colour is mostly white, but it can look greenish due to symbiotic algae. Freshwater sponges are subject to harsh environmental conditions, having developed a dormancy mechanism. When exposed to excessive cold or harsh situations, they form highly resistant gemmules that remain viable after the other part of the sponge dies. Once conditions improve, the gemmules germinate into a new sponge. These ancient invertebrates are sessile (fixed in one place) and filter water to feed on small aquatic organisms like protozoa, bacteria, and other free-floating life. A finger-sized specimen of S. lacustris can filter more than 125 l of water in a day. They are prey to ducks, crayfish, and various macro-invertebrates. Sponges play a key role in recycling organic matter and contribute to the primary productivity of freshwater ecosystems. Their presence in an ecosystem can be an indicator of  good water quality.

22/02/2021

#59 Arapaima

Native to the Amazon, the Arapaima, Arapaima gigas, is one of the largest freshwater fish globally - it can grow up to 3m, but nowadays it’s rare to find a specimen more than 2m long. Its Brazilian name, 'Pirarucu,' comes from two indigenous words – pira means fish and urucum means red, referring to the reddish marks towards the tail-end. During the mating season, males' red colours become more intense. After pairing, males clean the river bed with their jaws by pulling out any weeds or obstacles in a selected area, where they dig a puddle for the female to lay its eggs and fertilize them. The female stays nearby during the incubation period, while the male circles a bit further to scare off any predators. Arapaimas have gills and a modified respiratory swim bladder which works  like a lung – they need to return to the surface every 20 min to breathe air, making them easy to catch. They are economically and culturally important to many traditional communities. Climate change effects, habitat degradation, and increased demand on fish stocks put the Arapaima and livelihoods at risk. Local communities are leading the management and conservation of their resources with the support of the government and multiple organizations, including WWF. Check this video to see what local fishers say about the Arapaima and WWF-Brazil's work to support them. Learn more about this and other valuable freshwater fishes with The World's Forgotten Fishes report.

25/01/2021

#55 Diving bell spider

The Diving bell spider, Argyroneta aquatica, is the only spider to live underwater for most of its life. This Eurasian species inhabits eutrophic lakes, ponds, marshes, swamps, and slow-moving streams. To breathe underwater, their posterior body part called opisthosome is covered by fine hairs that trap air, being covered by a silvery envelope when they dive. They use plants from the dense aquatic vegetation to anchor their underwater silk webs. With their tiny body hairs, they collect air from the surface and release it in the web, creating an air-filled bubble - the ‘diving bell’, where the air is held by the surface tension between the silk fibres. The diving-bell works as an air deposit and as a physical gill - it absorbs dissolved oxygen from the water to meet the spiders’ metabolic oxygen requirements. They also use the bell to feed - after capturing the prey (generally aquatic invertebrates and small fish) by injecting venom into its body with their chelicerae (fangs), they carry it to the bell to consume it. Females use the bell to lay their eggs – they place an egg-filled cocoon in the upper region and lay on it for protection until hatching. The offspring only leave the bell once they have developed the fine hairs to build their first tiny diving bell.

08/02/2021

#57 LOWLAND TAPIR

The Lowland tapir, Tapirus terrestris, has a wide geographic range - from northcentral Colombia and east of the Andes, throughout most of tropical South America. Mostly found in the tropical lowland forests and wetlands of South America, they are often seen close to water which they use as a refuge against predators as well as a place to forage or cool off. This species is known for being a strong swimmer - able to cross rivers and even dive to feed on aquatic plants. Lowland tapirs can reach the size of a small pony, growing up to 1.8m and 225kg. They are primarily solitary, using their large teeth to grind up plants, fruits, and seeds at night and resting or hiding during the day. This species is listed as Vulnerable on the IUCN Red List of Threatened Species. Main threats to this species are habitat loss due to deforestation, hunting for meat, and competition with livestock. Due to their  long gestation period and generational time, tapirs are more ecologically prone to impact from prolonged hunting activity, making population recovery more difficult. 

11/01/2021

#53 Arafura File Snake

The Arafura File snake, Acrochordus arafurae, is one of the 153 known species of freshwater snakes globally. You can find this species in northern Australia and Papua New Guinea - swimming in  rivers, lakes, lagoons, floodplains and their associated wetlands. The Arafura is adapted to freshwater life, being considered an entirely aquatic snake – they forage in water and cannot survive without aquatic prey. Arafura File snakes are nocturnal and non-venomous. They feed exclusively on fish, which they immobilize by constriction - as they are agile and their skin flexible (not bendy) they can easily capture and hold onto their fish prey. They have nostrils on top of their head so they can breathe whilst underwater. Listed as Least Concern by the IUCN Red List of Threatened Species, this species populations viability depends on their freshwater ecosystems health.  

14/12/2020

#50 parading shrimp

A long time ago, a group of indigenous people in north-eastern Thailand discovered a distinctive phenomenon called ‘parading’– the synchronous mass migration of freshwater shrimps on land. Found in rivers and streams of Asia - Viet Nam, Yunnan (China), Laos, Thailand, and Peninsular Malaysia - Macrobrachium dienbienphuense is one of the species known to parade annually. During the rainy season, these adventurous shrimps leave the water collectively at night and walk upstream on land before returning to the river. But why would they leave the water? Recent research conducted by Watcharapong Hongjamrassilp in Nam Yuen district (Ubon Ratchathani province, Thailand), tested the hypothesis that parading was associated with spawning and breeding – and it is not. Evidence shows that the shrimps might leave the water to escape strong currents. Most of the parading shrimp were juveniles  – larger adults can face a stronger current, being less likely to parade – and not ready to reproduce. They walked from 5 to 20 meters - depending on river velocity and riverbank structure -  and some even stayed out of water for 10 minutes or more. To take in oxygen while on land, shrimp stayed within the rivers splash zone (20–40 cm from the river’s edge), and their exoskeleton seemed to trap water around their gills (similar to a reversed dive helmet). This mass migration is such a fascinating scene that it has been promoted as an ecotourism event in Thailand since 1999, drawing more than 100.000 visitors annually. Even though they are listed as Least Concern on the IUCN Red List of Threatened Species, recent evidence suggests that they are decreasing in number and body size. 

30/11/2020

#48 Jaguar

The iconic jaguar, Panthera onca, is the largest cat in the Americas. From Mexico to Argentina, jaguars typically inhabit regions with dense forest cover and water bodies, living near lakes, rivers, and wetlands. They are more strongly associated with water than any other Panthera cats. This majestic species is a confident swimmer known to cross large rivers, and it preys on aquatic species like turtles and even caimans. Thanks to their robust canines and a large head, jaguars can take down prey three to four times their own weight and bite through a crocodile skull or turtle shell – having the most powerful bite than any other big cats. Therein lies its name – ‘jaguar’ comes from ‘yaguar’, an indigenous word that means 'he who kills with one leap'. Sadly, they have been nearly eliminated from half of their historic range, with regional extinctions in El Salvador and Uruguay. Their preference for freshwater habitats - even within drier areas, they are only found around the main watercourses – quickly brings them into human-wildlife conflict, as they share the same resource as the expanding high-intensity agriculture and mining. Illegal wildlife trade, and habitat loss and fragmentation are other threats leading to the decreasing population of jaguars, listed as Near Threatened by the IUCN Red List. Their stronghold is in Brazil – in the Amazon region and the world’s largest tropical wetland, the Pantanal. However, the recent fires in both biomes magnify the threats to these populations - especially in the Pantanal, where a park known to hold the biggest concentration of jaguars globally has had 85% of its territory burned. 

16/11/2020

#46 Elephant fish

Campylomormyrus curvirostris has a very long trunk-like snout and occurs exclusively in water bodies within the Congo River basin. This strange-looking fish is a species within the family of freshwater weakly-electric fishes, the Mormyrids. This - mostly - nocturnal family is known to use their electric sense to communicate, actively find objects and food, and discriminate between fish from other species and their own. A specialized electric organ in the tail base generates a mild pulse-like Electric Organ Discharge (EOD). The electric pulse helps them to create a picture of their surroundings, in a similar way bats and dolphins use echolocation. C. curvirostris belongs to a particular group within their Mormyrids family – the Campylomormyrus –, which scientists say to have EOD play a key role in pair formation and mate recognition. The species in this group show remarkable differences in terms of EOD shape and duration, which enables them to perceive differences in the EOD generated by their peers. 

03/11/2020

#44 Vagrant darter

The Vagrant darter, Sympetrum vulgatum, is a dragonfly species found in all kinds of standing, largely unshaded waters. Larvae of almost all 5952 species of dragonflies and damselflies depend on freshwater habitats, spending most of their lives in this stage (generally one or two years) in the water. The nymphs live on the bottom of still and slow-flowing waters. To fully grow into an adult, the larvae catches and eats live prey at every opportunity. Both larvae and adults are predators, playing a significant role in the cycle of materials both in aquatic and terrestrial ecosystems. The Vagrant darter is a rare migratory species with a wide distribution – you can find this species eastwards to China and Japan, in Central and eastern Europe, and is likely common in large parts of its Asian range.

19/10/2020

#42 Platypus

The (Duck-billed) Platypus, Ornithorhynchus anatinus, is one of the most peculiar animals on the planet. This species uniqueness starts with the order of mammals to which it belongs - monotremes, mammals that lay shell-covered eggs but nurse their young. With its duck-like bill, webbed feet, a broad flat beaver-like tail, and an otter type of body and waterproof fur, this distinct mammal is adapted to and dependent on freshwater ecosystems. Hunting underwater, these bottom feeders have skin folds to cover their eyes and ears to prevent water from entering, and the nostrils close with a watertight seal. They find their invertebrate prey by detecting electrical signals through sensitive receptors on their bill, storing the catch in their cheek pouches until they reach the surface for consumption. They are also among the few venomous mammals – males have sharp stingers on the heels of their rear feet, using them most likely to settle territorial disputes. But don’t worry - although excruciating, the toxic blow is not fatal to humans, but known to kill mice, dogs, and other platypuses. Nowadays, you can only find the Platypus in the streams, lakes, and lagoons of eastern Australia and Tasmania – it was extinguished from much of its range due to hunting, habitat degradation, river fragmentation from dams, and entrapment or entanglement in fishing gear. 

05/10/2020

#40 Oriental darter

The Oriental darter, Anhinga melanogaster, is a waterbird known for its ability to swim to catch fish and other underwater prey. Found in Southern Asia, this beautiful bird lives in shallow inland wetlands, including lakes, rivers, swamps, and reservoirs. With their webbed toes, darters swim with their bodies submerged, while their long and sinuous neck remains visible above water. This behaviour display gives darters a snake-like appearance – accounting for their colloquial name “snakebird”. When foraging, they move slowly or hang motionless in the water, spearing fish with their dagger-like bill. Adapted to diving in shallow waters, darters are renowned for their extremely low buoyancy. Compared to other closely-related water birds like cormorants, they have uncommonly wettable plumage, thin and less spongy skin, denser bones, and smaller air sacs. Like other water birds, they are important bioindicators for the ecological conditions and health of wetland ecosystems. The Oriental darter is listed as Near Threatened by the IUCN Red List of Threatened Species, being regionally extinct in Thailand. Their populations are decreasing due to pollution, drainage, hunting, and the collection of eggs and nestlings. As they warrant conservation attention, Oriental darters are harboured by WWF’s Orissa Semi-Evergreen Rain Forests ecoregion. 

21/09/2020

#38 Nile Crocodile

The Nile crocodile, Crocodylus niloticus, is an aquatic predator that can reach up to 6 meters. Found in eastern, central, and southern Africa, this reptile giant inhabits a wide diversity of water bodies (rivers, lakes, swamps, and coastal estuaries), including the iconic Mara river basin. WWF’s recent report on Mara’s freshwater biodiversity identified the Nile crocodile as one of the four freshwater reptiles in the basin shared by Kenya and Tanzania. This species plays a key predatory role in the perennial river, which is the only water source for migrating wildlife in a drought year. They mostly feed on fish but can attack zebras, small hippos, porcupines, birds, and even other crocodiles. This impressive animal presents a caring nature as a parent – females ferociously guard and defend their nests until the eggs hatch, often helping hatching babies emerge with their teeth and carrying them inside their mouths to the water. This species also presents other sophisticated behaviour like complex communication and coordinated group hunting, being considered highly intelligent. If you ever thought that a crocodile has a dinosaur-like feature, you were not far off - crocodilians are more closely related to dinosaurs and birds than to most reptiles. Between the 1940s and 1960s, the Nile crocodiles populations were depleted throughout much of their range due to hunting. Thanks to the protection afforded by national legislation and international trade conventions (CITES), populations have recovered in many regions.  

24/08/2020

#34 raft spider

Meet the European spider of the year: the raft spider, Dolomedes fimbriatus, one of the largest native spiders in the region. Found mostly in moorland and wetlands, they inhabit water margins of ditches, ponds, and slow-flowing streams, showing remarkable adaptations to this habitat. This free-living hunter spider moves skilfully on the water surface, overpowering its prey without using a web. They sit on emergent water plants or the water surface in a hunting position, waiting for unaware (aquatic) insects, tadpoles, and small fish. Thanks to its thick coat of body hairs, the raft spider can lay its whole body on the water, relying on surface tension to remain above the water. But when in danger, they can dive underwater and come out dry – an air bubble forms around their body, which bursts after they go back to the water surface. Raft spider females constantly carry their spherical egg-sacs (with up to 1000 eggs!) in their mouthparts called chelicerae (pair of appendages in front of the mouth). When the eggs are close to hatching, the female hangs the eggs’ cocoon in vegetation near the water’s edge, guarded and enclosed by silk threads. Unfortunately, the Euro-spider of the year is becoming rarer and more vulnerable, due to the destruction of its habitat – building work on river banks and removing reed beds and water lilies - and climate change.
 

07/09/2020

#36 pink Amazon river dolphin

“Once the sun goes down, the boto morphs into a handsome young man dressed in white to seduce young women of local villages, leaving them impregnated before the sun comes up to return to the river once again as dolphins.”
 
That’s not the only myth surrounding the pink Amazon river dolphin, Inia geoffrensis. Also known as “boto cor-de-rosa” or boto, you can find this mystical animal throughout the Amazon and Orinoco river basins in South America (strictly speaking, also in the Araguaia basin). Unlike other river dolphins, the boto has a flexible neck that moves its head left and right to maneuver through the flooded forests for food and shelter. With their long snout, they feed on fish and other aquatic organisms like turtles and crabs. Locals believe that botos possess magical powers. If you swim alone in the river, you could be whisked away by the boto to “Encante”, a magical underwater city. For many tribes, including WWF, the boto is sacred. Listed as an Endangered species by the IUCN Red List, the magical boto can’t escape threats such as dams, mercury poisoning due to gold mining, and being killed in fishing nets or to be used as fish bait. Through initiatives such as River Dolphin Rivers  and South American River Dolphin (SARDI), WWF works with local communities, governments, and other NGOs to develop regional and innovative approaches to protecting this species and their habitats. Since they are indicators of environmental river health, the pink river dolphin was chosen as the Ambassador of the Amazon rivers! With such seductive powers, that was an easy call.  

 

10/08/2020

#32 Sacred lotus

To shine some light on these trying times, we bring you the Sacred lotus, Nelumbo nucifera. This perennial aquatic plant has been revered in many cultures for thousands of years, mostly as a symbol of purity. Its name derives from its significance in the religions of Buddhism and Hinduism: a plant that rises from a humble origin, rooting itself in the muck below and ascending high above the water untainted. The leaves can sit directly or above the water, and the distinguished lotus flower blooms gloriously above the leaves. The Sacred lotus’s uniqueness is in all parts of the plant -  the roots, stems, leaves, and seeds have all been used as a food source and in traditional medicines, especially in Southeast Asia. Also known as the Asian lotus, this species has also intrigued the scientific community for presenting remarkable features such as leaf super-hydrophobicity (i.e., water repellence) -  known as the “Lotus-Effect” -, and seed longevity. Their leaves have a special waxy coating that sheds water and dirt, suggesting that the Lotus-Effect may play an important role in protecting plants against pathogens and contaminations. Lotus fruits were found buried underground over 1300 years in China could still be germinated, being seed longevity another fantastic feature of this sacred aquatic plant.
 

27/07/2020

#30 Mekong Giant Catfish

Able to reach a length of up to 3m and over 300kg, the Mekong giant catfish, Pangasianodon gigas, is one of the world’s largest fish! Native and endemic to the Mekong River, this species can live to be 60 years old. These migratory fish swim around Vietnam, Cambodia, Laos, and Thailand – most likely found in the Lower Mekong river basin. Sadly, they are one of the most endangered fish in southeast Asia. Listed as Critically Endangered by the IUCN Red List of Threatened Species, this species faces overharvesting for local and commercial fisheries, habitat loss and pollution, intentional hybridization for aquaculture, and bag-net fishery of Cambodia. In the last 50 years, the total number of fish declined by 90%. This river giant is a highly-valued food resource, not because it is a delicacy but because it has a god-like status - some believe it brings good luck forever once eaten, bestowing the gifts of wisdom and long life. Intentional fishing is currently banned in most areas, but this species is still harvested incidentally as by-catch. As the Mekong giant catfish most probably migrates long distances, dams’ construction is also a threat. Dams likely prevent them from reaching their spawning site and may cause extinction - there is only one known spawning site in Thailand, and the blockage of this waterway by two dams might be their demise.

13/07/2020

#28 Ywangan crocodile newt

New species are often discovered in the biodiversity hotspot region of the Greater Mekong - over 2,216 new species have been found since 1997 (that’s two species per week on average! Check this report for more). Recently, researchers discovered a new species of newt. With a coloration almost solid black, the Ywangan crocodile newt, Tylototriton ngarsuensis, differs from its bright orange cousins, besides having a shorter head, larger size, and breeding later in the year than other closely related species. Found in Ngar Su Village, in Myanmar, this amphibian is so common that the villagers have long known about it. One of the researchers, Lee Grismer, said that “even in populated areas, new species can be found and in doing so underscores the need for field work so we can more accurately catalogue the biodiversity of this planet.” Especially when these species face threats such as habitat destruction, harvest for the illegal pet trade, and medicinal trade. Besides Lee Grismer, this new species was discovered by his colleague from La Sierra University, Marta S. Grismer, Perry L. Wood Jr. (University of Kansas), Evan S.H. Quah (Universiti Sains Malaysia), Robert E. Espinoza (California State University) Matthew L. Murdoch (Villanova University, USA), and Aung Lin (Fauna and Flora International, Myanmar). 

29/06/2020

#26 Fisherman bat

This week we present a flying mammal that can also fish – the Fisherman bat, Noctilio leporinus. Also known as the Greater Bulldog bat, this fishing bat inhabits tropical lowlands from Southern Mexico to Northern Argentina, foraging over streams, ponds, rivers, and lagoons. The Fishermen bat can swim and take flight from the water, and feeds on aquatic insects, fish, frogs, and crustaceans. Many bats are associated with freshwater, but fishing bats possess adaptations of their posterior limbs to capture prey. Fishing bats tend to have 1.8 to 3.9 times larger feet, and their digits – ''toes'' - are elongated, ending with hook-like claws. When fishing, these bats fly within 20 to 50 cm of the water surface, echolocating to find ripples that signal underwater prey. Once they notice the disturbance, they fly closer over the water  (four to 10cm) with their back legs and feet held straight down, “scraping” the water to gaff fish with their forward-facing claws. With the fish in their claws, they rise in the air and transfer the prey to their mouth. The Fishermen bats are also safe “flyers” – when on a collision course with other fellow Fishermen, one bat "honks" at the other! They can do this by adjusting the frequency of its echolocation call.

15/06/2020

#24 Water scorpion

The Water scorpion, Nepa cinerea, might look like it, but it is not a true scorpion. With its leaf-shaped and flattened body, this intriguing species is actually a water bug – an insect adapted to freshwater ecosystems. Frequently found in the Palaearctic region – a large ecozone including Europe, Asia, northern Africa, and the north and central parts of the Arabian Peninsula – the Water scorpion swims via strong strokes, and crawls and clings to water plants. When at rest, they slyly hide upside-down amongst the vegetation, letting their breathing tube out of the water to catch atmospheric air. They track their prey furtively, approaching the fry of insect larvae with considerably slow, almost inconspicuous movements. As soon as the unaware prey is within some millimetres, the Water scorpion swiftly embraces its victim with its raptorial front legs. 

18/05/2020

#20 Chambo

Endemic to Lake Malawi in East Africa, the Chambo, Oreochromis karongae, likes to swim around in loose shoals. Like other fishes of the Oreochromis genus, they present a curious form of parental care called maternal mouthbrooding. During spawning, soon after the male has fertilized the eggs, the mother puts them in her mouth until they hatch – a fascinating strategy to protect their offspring. The Chambo is also very important for local subsistence and commerce, being the most valuable food fish in Malawi. For this reason, they are threatened by overfishing. In the 1990s, the populations of the Chambo collapsed, with a 70% decline within ten years  –  unsurprisingly ending up listed as Critically Endangered by the IUCN Red List of Threatened Species. 

01/06/2020

#22 Flatworm

The flatworm, Crenobia alpina, is not your typical freshwater star species. With two primitive eyespots giving them a charismatic look, this species can grow up to 15mm in length (take a look at them moving here). This harmless flatworm is a predator found most frequently in cold and clear mountain streams. Their preference for cold waters comes with a price in a climate-changing world – a 40-year study shows that this species (as well as other invertebrates) has vanished from Llyn Brianne and much of Wales when the temperature of the streams rose. As the professor of ecology at Cardiff University’s school of biosciences, Steve Ormerod says, “the loss of freshwater organisms is a hidden tragedy, and it’s amazing how much is left to discover”.

27/04/2020

#17 Lesser Flamingo

This week we celebrate the exquisite and outstanding Lesser flamingo, Phoenicopterus minor. This species is “lesser” only in the sense that it is the smallest of the six species of the flamingo family. They have the biggest population of all flamingos, with two to three million individuals. They are also tolerant to extreme environments – their habitat is hostile for many animals and plants due to high temperatures, salinity, and alkalinity, but the Lesser flamingos are superbly adapted. Living around lagoons or lakes of Africa and India, they walk through shallow waters with their thin, pink legs as they feed - bending their necks downward to filter their food. It is thanks to their diet - rich in carotenoid pigments - that their feathers become remarkably pinkish. The bright pink colouration may function as a signal of parental capability, attracting mating partners – as parents take turns in brooding, one of them needs to look for food efficiently. The Lesser flamingo also shines with their spectacular courtship dance: groups of more than 1000 birds march together with a straight-up posture like soldiers, moving their heads and necks synchronously. These extraordinarily social birds also synchronize other activities such as brooding, to “crowd-protect” their offspring. A recent study even suggests that they form lifelong friendships – making it impossible not to fall for the flamboyant flamingo.

13/04/2020

#15 Irrawaddy river dolphin

To celebrate Dolphin Day (April 14th), we present to you the charming Irrawaddy river dolphin, Orcaella brevirostris. With a rounded head and no beak, the three subpopulations of this distinctive dolphin can be found swimming along three rivers in South and Southeast Asia - Ayeyarwady River (Myanmar), Mahakam (Indonesia) and Mekong (Cambodia). Recent estimates indicate that there are around 79 individuals left on the Ayeyarwady, indicating this is a species right on the edge. Nonetheless, less than 300 freshwater Irrawaddy dolphins still live, including in Cambodia and Indonesia. Although they are not directly exploited, these river dolphins suffer many threats, including entanglement in gill nets and illegal fishing activities such as electrofishing - which unsustainably removes their food source. Nevertheless, fishing activities can be done in harmony with river dolphins. In the Ayeyarwady river, the local fisherfolk use a traditional fishing method that portrays a unique relationship with the dolphins, called “Cooperative fishing”. The fishermen “call” the dolphins by tapping a stick repeatedly on the side of the boat. If the dolphins are up to fishing, they chase shoals of fish towards the waiting nets and signalize the location of the prey. Once the fishermen cast their nets, the dolphins snatch the escaping fish. As this extraordinary interaction can be seen only in a few places around the world, many initiatives – such as our River Dolphin Rivers - work on the conservation of both the Irrawaddy dolphin and the fishermen’s way of life.  

06/04/2020

#14 Surinam toad

The Surinam toad, Pipa pipa, is a fully aquatic amphibian known for its unusual appearance and fascinating – some might argue horrifying - parental care adaptations. You can find this species mostly in the slow-flowing waters of the Amazon Basin in South America, generally hiding under submerged leaf-litter - with their extremely flattened body and triangular-shaped head, they blend in for looking like a mottled brown leaf. This species also exhibits a unique courtship behaviour: after attracting a mate by making clicking sounds, the male toad mounts onto the back of the larger female and embraces her around the waist - if she is receptive, their mating act starts, and the pair displays some aquatic somersaults that can last for more than 12 hours. With the help of the male, the fertilized eggs are rolled up onto the back of the now upside-down female – the eggs sink into the puffy and swollen skin and are almost completely enveloped by it. The pregnant toad carries the developing offspring for three to five months until the “toadlets” are ready to punch their way out of their mother’s skin pockets, in a bizarre scene that can make many people shiver.

23/03/2020

#12 Arctic char

World Water Day was on March 22nd, and to celebrate our most precious resource, we introduce you to the northernmost freshwater fish in the world: the beautiful Arctic char, Salvelinus alpinus. These circumpolar fish species inhabit cold and clean waters around the North Pole. Numerous local freshwater populations of Arctic char exist in all Arctic states, plus a smaller number of sea-run populations - where fish can grow up to 10kg in weight. The Arctic char suffers from increasing temperatures due to climate change, especially the more southern populations in the Alpine regions, which can be at risk of extinction - water temperature and quality are significant factors in the survival of their sensitive eggs. According to the first report on The State of the Arctic Freshwater Biodiversity (2019), climate warming increasingly threatens freshwater biodiversity in arctic lakes, rivers, and wetlands. The report also suggests that the Arctic char – as well as other cold-water species endemic  to the Arctic – are likely to suffer regional losses, or even local extinctions as a result (find out more with this great article). Similarly, the 2019 report of the Intergovernmental Panel on Climate Change (IPCC) states that changes in the cryosphere will alter freshwater communities - range shrinkage and extinction of some species can cause regional biodiversity to decrease. WWF Finland has been involved in a conservation project to strengthen the population of Critically Endangered Lake Saimaa Arctic char. Also good news exists: exploitation of the northern Arctic char population in Finland has decreased at the same time with improved protection, leading to improved conservation status in the Red Book of Species for Finland –  bending the curve in freshwater species does exist!

09/03/2020

#10 Victoria water lily

A long time ago, a young warrior called Naiá, from a Brazilian Amazonian tribe – “Tupi-guarani”– would dream about the day she would meet with Jaci, the moon. According to the legend, Jaci was a goddess who every night would kiss the most beautiful women of the tribe, and before hiding behind the mountains, she would pick her favourite to transform the woman into a star. Every night, Naiá would walk around the hills searching for Jaci. One day, after seeing the reflection of Jaci on a lake, she threw herself inside the lake and drowned. The moon compassionately decided to reward Naiá for her sacrifice, transforming her into a star of the waters – the Victoria water lily, whose white flower only opens at night and changes to pink when the sun rises. 
The myth of the Victoria water lily above is a fragment of the memory of WWF's Paula Martinelli, who remembers hearing this story growing up in Brazil. The Victoria water lily, Victoria amazonica, is native to the Amazon biome and the symbol of the Amazon state of Brazil. The legend of the Victoria water lily has some truth to it – the white flowers only bloom at night, its colour changing to pink or ruby red after spending the evening exuding a strong odour to attract beetles to pollinate them. The flower closes its petals in the morning, hopefully trapping the beetles and releasing pollen on them. They open again in the following evening, releasing the beetles to transport their pollen to other flowers – they now have different colours and are scentless, being less attractive to the beetles. This fascinating adaptation avoids fertilization by its own pollen, increasing the genetic variability of the world’s largest water lily. 

02/03/2020

#9 Beluga Sturgeon

To celebrate World Wildlife Day (tomorrow on March 3rd), this week we present to you the majestic Beluga sturgeon! Even though there is still a debate on which is the largest freshwater fish in the world, the Beluga sturgeon, Huso huso, is undoubtedly the largest migrating freshwater fish – with a record of 1,571 kg and 7.2 m, this female was caught in 1827 in the Volga estuary. But this is history -  nowadays, you can seldom observe a length above 2m. This species has been recorded swimming in the basins of the Caspian, Black, Azov, and Adriatic Seas. The migration of the Beluga sturgeon was predictable, and as a huge fish, they were an easy target, providing abundant food for many people. Its current native wild distribution is restricted to the Black Sea (Danube and Rioni) and the Caspian Sea (Ural). It does occur in the Azov Sea and Volga River, but as stocked fish. Due to historically severe overfishing and poaching in estuaries and rivers, the Beluga sturgeon is listed as Critically Endangered (CE) by the IUCN Red List of Threatened Species. This species is wanted for its meat and caviar - one of the most valuable products on the food market. Their caviar is considered top class caviar and is among the most expensive – you can buy 30g in London at the modest price of €420, which adds up to a price of €14.000 per kg. The beluga sturgeons’ eggs can only be legally obtained from aquaculture. Unfortunately, illegal wild caviar is still in demand on the black market by customers who consider "wild" as the "real" thing. IUCN also states that sturgeons are more critically endangered than any other group of species – 23 of all 27 known species are considered to be threatened with extinction. The mighty Beluga sturgeon can live for over 100 years, spending several years in the sea and migrating longer distances than any other sturgeon – more than 1000km. Because of their particular long life cycle, the recovery of its heavily depleted stocks will need several decades. But they can still be saved. WWF is working together with communities, civil society, companies, scientists, law enforcement authorities and governments across the world to rebuild their population. For example, our Sturgeon initiative is tackling the illegal caviar trade and enhancing the health of river systems. And, last year, WWF helped to save a Beluga in the Danube.

17/02/2020

#7 Grey Crowned crane

The Grey Crowned crane, Balearica regulorum, calls attention for its beautiful colours and a majestic golden plumage on their head unfolding like a crown. They are also known for displaying playful behaviours such as dancing. Mainly a form of socialization and pair formation, other species of cranes are also famous for their dance moves. You can find the Grey Crowned crane “performing” in the eastern and southern regions of Africa, where they are also a culturally important species – considered icons of Africa’s wetlands and savannahs, besides being the national bird of Uganda. However, it’s not all glamour for the Grey Crowned crane. Listed as Endangered by the IUCN list of threatened species, they are threatened primarily by illegal trade, disturbance, and habitat loss. The Global Wetland Outlook 2018 states that up to 87% of wetlands have been lost since 1700. The Grey Crowned crane and the other 14 living species of cranes need wetlands as stepping stone corridors –  where they can find a safe harbour to sleep, rest, nesting, and rearing the young. As cranes are among the most threatened bird families in the world, WWF has joined the International Year of Crane 2020, announced by the International Crane Foundation and the Crane Working Group of Eurasia. The Amur River basin is the flyway and breeding grounds of no less than six species of cranes, and WWF will be working with partners in the region to strengthen the conservation of both wetlands and the majestic cranes.

27/01/2020

#4 Yangtze Finless porpoise

The Yangtze Finless porpoise, Neophocaena asiaeorientalis asiaeorientalis, as the name suggests, lives in the Yangtze River and is the world’s only freshwater porpoise – and one of only five surviving species of freshwater cetacean. Unfortunately, there are only an estimated 1,012 finless porpoises left in China’s greatest river and they are listed as Critically Endangered on the IUCN red list of threatened species due to a host of threats, including water pollution, overfishing, boat traffic, sand mining, and river fragmentation. Many finless porpoises have also been killed after becoming accidentally entangled in gill nets – something which contributed to the extinction of the Yangtze freshwater dolphin, the Baiji (Lipotes vexillifer). But there is still hope for the Yangtze finless porpoise. Led by the Chinese government, conservation efforts – involving WWF, partners and local communities – have helped to drastically slow the annual decline in the finless porpoise population, including relocating animals to safer habitats away from the river’s mainstem to create new breeding populations. Huge amounts of work still need to be done to secure the survival of the species and WWF will continue to be at the forefront through its global River Dolphin Rivers initiative. This initiative is working on the development of smart river pingers in an effort to prevent future entanglement in gillnets. For many years, the finless porpoise had little to smile about but thanks to the combined efforts of the government, communities and conservationists, there is now a chance that the species can turn the corner and that its population will finally start to increase.

13/01/2020

#2 Matamata turtle

The matamata turtle, Chelus fimbriata, is one of the world’s largest freshwater turtles – and undeniably one of the weirdest too. Found in the Amazon and Orinoco basins, their unmistakable appearance is the combination of a leaf-shaped head, a long pointy snout, a rough tuberculate flat shell, and an elongated, thick neck with protuberances. The bizarre look is the result of a unique adaptation for feeding and blending in - they are incredibly specialized feeders that wait for dinner to come to them. When unknowing fish approach them to see if the protuberances on their neck are edible, they quickly stretch their neck out and open their mouth to create a vacuum that swallows their prey whole.