New type of gillnet may help endangered dolphins

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Bycatch in gillnets is a serious threat to the franciscana dolphin (Pontopoia blainvillei), Brazil's most endangered dolphin. Gillnets are virtually invisible barriers for these dolphins, who frequently get trapped and drown in them. 

A collaborative project to reduce dolphin bycatch in gillnets, conducted by Projeto BioPesca with the Bycatch Consortium and funded by the Lenfest Ocean Program, was recently featured in Brazil's newspaper O GLOBO, "Novo tipo de rede promete ajudar a proteger toninhas". The organizations are working with fishermen in Praia Grande, Sao Paulo, testing three different types of gillnet: barium sulfate infused nets, rigid nets, and standard gillnets. The barium sulfate in the nets should increase their acoustic visibility, allowing dolphins to 'see' and avoid them. However, infusing the nets with barium sulfate may also make the nets stiffer, so the rigid nets are also being tested to determine whether the barium sulfate nets are successful due to their acoustic properties or physical. Observers are currently accompanying the fishermen to evaluate the effectiveness of the different types of nets for reducing dolphin bycatch and catching fish. Although there are no conclusive results yet, researchers hope that this project will aid in the global effort to reduce dolphin bycatch.

Photo: Yaqu Pacha