Each year in the Pacific Ocean, millions of baited hooks are set on longlines in order to catch tuna, as well as other fish like swordfish and mahi mahi. However, the hooks also catch marine turtles, sharks, billfish, seabirds, and marine mammals, as well as juvenile fish and other fish species. The bycatch problem is perhaps most acute for marine turtles, especially the critically endangered Pacific leatherback turtles, whose nesting female population has decreased by 95% since 1980.
Critical fisheries
What was the last seafood meal you ate? Whatever it was, and wherever it was caught, it is likely that untargeted marine life – often including threatened species –died along with the fish on your dish.
Indeed, 3 of the 5 most-traded seafood products globally - tuna, shrimp, and whitefish - come from fisheries that throw a significant part of unwanted fish (bycatch) over board.
In all cases bycatch threatens the survival of certain species.
WWF has identified the following critical fisheries that need to be addressed urgently.
In all cases bycatch threatens the survival of certain species.
WWF has identified the following critical fisheries that need to be addressed urgently.
Pacific longline fisheries
Silky shark caught by the fin on an illegal longline hook.
Tropical shrimp trawl fisheries
Trawler catch, Borneo/Malaysia.
Used to catch the vast majority of tropical shrimp, trawl nets entrap 5-20kgs of bycatch for each kilogram of shrimp. Species caught include marine turtles, juvenile fish, cetaceans, dugongs, sharks, seahorses, seabirds, sea snakes, and corals and other invertebrates such as crabs and starfish. In the Gulf of Mexico, for example, shrimp trawlers catch as many as 35 million juvenile red snappers each year, enough to have an impact on the population. As a further example, in the Gulf of California, entanglement in shrimp trawler nets threatens the world's smallest and most endangered small marine cetacean - the vaquita - with potential extinction.
North Atlantic trawl fisheries
Bycatch of juvenile cod
The iconic Atlantic cod was once responsible for one of the most productive fisheries in the world, generating such wealth that it played a pivotal role in the economic and social development of the northern hemisphere. Relenteless overfishing has now depleted stocks to critically low levels and stock recovery is prevented because large numbers of juvenile cod are caught in trawl fisheries that target other fish such as haddock, flatfish (e.g. halibut, plaice) and Nephrops (a small lobster species). For example, on Canada’s southern Grand Banks, where cod fishing is now banned, up to 90% of the estimated remaining cod biomass was caught as bycatch in 2003.
