DISTURBED, HUNGRY AND LOST – CLIMATE CHANGE IMPACTS ON WHALES

The report Whales in hot water? highlights the growing impacts of climate change on cetaceans. They range from critical changes of ocean temperature and salinity, caused by melting of ice and increased rainfall, to sea level rise, loss of icy polar habitats, the decline of krill populations and major shifts in plankton distribution in key areas.

Krill – a tiny shrimp-like marine animal that is dependent on sea-ice – is the main source of food for most of the great whales, and is very sensitive to changes in oceanographic conditions.

The impacts of climate change add to disruptions from other human activities, such as chemical and acoustic pollution, collisions with ships, and entanglement in fishing gear (which kills more than 1,000 cetaceans every day).

“In the past, many cetacean species have managed to adapt to changing environmental conditions,” said Mark Simmonds, International Director of Science, WDCS. “But the climate is now changing at such a fast pace that it is unclear whether or how whales and dolphins will be able to adjust.”

Climate change impacts are greatest in the Arctic and the Antarctic. According to the report, cetaceans that rely on polar, icy waters for their habitat and food resources – such as beluga, narwhal and bowhead whales – are likely to be dramatically affected by the reduction of sea-ice cover. Coastal communities have already witnessed big changes in whale behaviour, numbers and sea-ice conditions.

And as sea-ice cover decreases, there will be increased human activities, such as commercial shipping, oil-gas and mining exploration and development, and military activities in previously untouched areas of the Arctic.

“This will result in much greater risks from oil and chemical spills and acoustic disturbance and more collisions between whales and ships,” said Peter Ewins, Species Conservation director for WWF–Canada.

There are many known threats posed by human activities to the survival of cetacean species, with accelerating climate change adding to the list in a very significant way. Managing all activities that contribute to these pressures on cetacean populations is now clearly essential to their long-term survival.

“Canada’s whale populations, such as the endangered North Atlantic right whale, rely on the abundance of food in our waters,” said Tonya Wimmer, Species Conservation Manager for WWF-Canada. “Climate change, due to its effects on ocean temperature, will affect the available food supply and has the potential to severely impact whale populations and jeopardize their future. Climate change could be the nail in the coffin for the last 300 or so endangered North Atlantic right whales, as the survival of their calves has been directly related to the effects of climate variability on prey abundance”.

The Whale and Dolphin Conservation Society and WWF are urging governments to cut CO2 emissions by at least 50 per cent by the middle of this century. The latest report of the Intergovernmental Panel on Climate Change shows it is possible to stop global warming if the world’s emissions start to decline before 2015.

The two conservation organizations call further on the IWC to facilitate research on future impacts of climate change on cetaceans; elaborate conservation and management plans in light of the climate change threat; and increase efforts and resources to fight all other threats to cetaceans.