Whales, dolphins and porpoises suffer high death rate as by-catch in fishing nets – UN

Large-scale fishing operations are seriously threatening the lives of the majority of toothed whale populations, which include dolphins and porpoises, warned a new United Nations Environment Programme (UNEP) report released today.

The report, launched on the Convention on the Conservation of Migratory Species of Wild Animals (UNEP/CMS) website, noted that some 86 per cent of all toothed whale species are at risk from entanglement and death in gillnets, traps, weirs, longlines and trawls.

Lack of food and forced changes in diet as a result of overfishing pose additional threats to 13 of the 72 toothed whale species.

“During the International Year of Biodiversity, the Convention on Migratory Species continues to address major threats such as by-catch, ship strikes, ocean noise impacts and climate change to safeguard these charismatic marine mammals,” said UNEP/CMS Executive Secretary Elizabeth Mrema.

“Governments need to enhance their efforts towards implementing targeted action plans under the Convention,” added Ms. Mrema.

UNEP said that toothed whales make their home in a wide range of marine and freshwater habitats, from the Arctic to the tropics, with some species living in large river systems such as the Amazon, Ganges, Indus and Yangtze.

According to UNEP, the Baiji River Dolphin, which used to live in the Yangtze River, is probably extinct, and the Vaquita porpoise from the northern Gulf of California is facing the same fate with only 150 individuals remaining in the wild, with entanglement in fishing gear claiming an unsustainably high number of both species.

Many populations of toothed whales were at one point hunted almost to extinction and 50 species continue to be hunted, often at unsustainable levels. More recently, the ingestion of plastic debris or the effects of pollution by an ever-increasing cocktail of chemicals have been reported in 48 toothed whale species.

In addition, habitat degradation from dams and withdrawal of water from rivers and lakes threatens 18 species while ship strikes have a serious impact on 14 species, and noise caused by seismic explorations, marine construction projects and military sonar pose increasingly greater threats to these marine mammals, noted UNEP.