Toothed whales are currently suffering from a major threat which is unsustainable loss from by-catch in fishery operations. 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.
These are among the findings of a report launched today on the website of 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.
This encyclopaedia on all 72 species of toothed whales 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.
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. "
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.
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.
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.
Data collection on the distribution, behaviour and migration of toothed whales, as reflected in research for the CMS can facilitate the development and implementation of action plans that can help reduce the threats to many whale species. Being an official partner of the International Year of Biodiversity, the Convention on Migratory Species has joined the Convention on Biological Diversity (CBD) to raise awareness of the importance of biodiversity on a global scale. CMS, which has been recognized as CBD's lead partner on issues regarding migratory species, continues to take steps to stress the importance of biodiversity for our well-being and enhance efforts to reduce the rate of biodiversity loss.