Whales and dolphins worldwide threatened by bycatch & human activities

Vaquita, the world's rarest cetacean. There are probably less than 150 left. Photo credit Omar Vidal.

86% toothed whale species threatened by bycatch
February 2010. Toothed whales (Inc. dolphins) are currently suffering from a major threat from by-catch in fishery operations causing unsustainable loss. For 86% of all toothed whale species, entanglement and death in gillnets, traps, weirs, purse seines, longlines and trawls poses a major risk. Lack of food and forced dietary shifts due to overfishing pose additional threats to 13 species.

Sperm whale is only large toothed whale
Based on the Review of Small Cetaceans published by CMS in 2003, this report includes the Sperm Whale as the only large toothed whale as well as the Australian Snubfin Dolphin and the Guiana Dolphin as new species. Since 2003, the conservation status of the toothed whales has worsened dramatically. The Baiji River Dolphin, which used to live in the Yangtze River, is now probably extinct as no living specimens have been documented in the wild since 2002. With only 150 individuals remaining in the wild, the Vaquita, a porpoise living in the northern Gulf of California, is facing the same destiny. Entanglement in fishing gear claimed an unsustainably high death toll on both species.

The Baiji River Dolphin was declared extinct in 2008. Credit ZSL.

The report covers all 72 species of toothed whales and includes the most recent scientific findings on the distribution, migration, behaviour and threats to this group of whales. Maps showing the currently known distribution of each species were provided by IUCN and the Global Mammal Assessment.

By-catch, ship strikes, ocean noise
UNEP/CMS Executive Secretary Elizabeth Mrema said: "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. Governments need to enhance their efforts towards implementing targeted action plans under the Convention. "

Lack of knowledge about 41 species - 6 on the brink of extinction
Toothed whales occur in a wide range of marine and freshwater habitats, from the Arctic to the tropics. Some species live in large river systems such as the Amazon, Ganges, Indus and Yangtze. For 41 of all toothed whales species, our knowledge is too limited to even know if they are threatened or not. At the same time 6 species of toothed whales that are listed on Appendix I of the Convention are on the brink of extinction.

Toothed whales & dolphins
Many populations of toothed whales were hunted almost to extinction and 50 species continue to be hunted, often at unsustainable levels. Ingestion of plastic debris or the effects of pollution by an ever increasing cocktail of chemicals have been reported for 48 species. 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. Noise caused by seismic explorations, marine construction projects as well as military sonar pose ever increasing threats to these marine mammals.

These are among the findings of a report launched by the Convention on the Conservation of Migratory Species of Wild Animals (UNEP/CMS). A corresponding poster, available online, shows, for the first time, all toothed whale species sorted according to their conservation status as defined by the IUCN Red List of Threatened Species.