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This important joint action was undertaken by the WWF Living Amazon Initiative, WWF Brazil and the Mapsmut organisation and is designed to glean information on fish species in the Juruena River. The objectives are twofold: electronic registration and remote tracking of large individuals by tagging them with chips and a survey of all fishing activities in the area.

WWF begins study of fish species in the Juruena National Park

Matrinxã (Matrinsham)

The environmental organization WWF, through its Living Amazon Initiative and WWF Brazil has begun a study of the migratory fish species known locally as matrinxã (matrinsham) in the region of the Salto Augusto Falls inside the Juruena National Park, a protected area that encompasses areas of the Brazilian states of Amazonas and Mato Grosso.

The matrinxã (Brycon amazonicus) is a fish renowned for its silvery brilliance and delicious flesh. Adults can be up to 70 cm long and weigh 4 kilos and they are much appreciated by sport anglers. More importantly, they are an source of protein in the diet of local communities.

The study being undertaken by WWF is concentrated in the region in the waters immediately above and below the beautiful Salto Augusto falls, located inside the National Park’s limits. There researchers captured ten specimens of matrinxã above the falls and ten below and they will be unmaking genetic tests  to discover whether  the communities of matrinxãs above and below the falls are exactly the same species or not.

The 20 specimens are now at the laboratories of the Federal University of Mato Grosso in the city of Cuiabá and they will be studied by a team led by fish zoology specialist Paulo Cesar Venere. The study is expected to be finalised in July.

In addition, the field researchers have collected samples of the fins of 15 other specimens to provide more information to support the genetic testing of the matrinxãs.

The Migratory Species of the Juruena River Expedition to the surrounding regions of the Juruena National Park,  which lies in the Tapajos River basin,  began on May 12 and is scheduled to finish on May 24, World Fish Migration Day (...). Learn more.
News Section

Why is it so important to study migratory fish species?

Small fishes swimming up a waterfall, Juruena National Park, Amazon, 2014. 
© Zig Koch / WWF

According to the definition most widely accepted by ichthyologists, scientists who study fish zoology, migratory fish are those that regularly change their habitats, undertaking “vertical” migrations upstream and downstream in rivers and entering and leaving lakes and streams, or that make long journeys in the oceans (...). Learn more.

Amazon survey investigates fish and communities in region targeted for hydropower development

The last report by a conscious Langsdorff was written down at the Salto Augusto falls. 
© Zig Koch

WWF has launched a 12-day survey of Brazil’s Juruena River focusing on migratory fish species and how communities near the river use its resources. The Juruena River flows through (...). More.


Photo Gallery of the Expedition

Small fishes swimming up a waterfall, Juruena National Park, Amazon, 2014. rel= © Zig Koch / WWF