Rising sea-surface temperatures and sea levels, receding ice caps and changes in ocean circulation could have a significant impact on the world’s fragile marine ecosystems, said the report, forcing essential prey resources to relocate and causing certain marine habitats to be diminished.

At greatest risk are those species that exist in, or require, a limited or specific habitat range, including the narwhale, bowhead and beluga whales (above), for which sea-ice forms an important part of their habitat, and the vaquita porpoise, which has the smallest distribution of any cetacean, living only in the northern part of the Gulf of California.

The big question, according to the study, is how quickly threatened mammals will be able to adapt to the significant changes in their habitats. The report calls for governments and conservation bodies to address the issue. “Marine ecosystem modellers and marine mammal experts will need to work together to make such assessment and conservation plans as robust as possible,” wrote the authors of the report, Mark Simmonds, director of science at the WDCS, and environmental scientist Stephen Isaac.

July 2007