November 23, 2012
Varied Diets Of Dolphins And Whales Key To Their Survival
April Flowers for redOrbit.com - Your Universe Online
High-energy prey make for high-energy predators in the marine world. Survival, for those predators, depends on sustaining the right kind of high-energy diet, so not just any prey will do.
"The conventional wisdom is that marine mammals can eat anything," says Andrew Trites, a marine mammal expert at UBC. "However, we found that some species of whales and dolphins require calorie rich diets to survive while others are built to live off low quality prey–and it has nothing to do with how big they are."
Comparing the diets of 11 species of whales, dolphins and porpoises in the Northeast Atlantic Ocean allowed the team to find differences in the qualities of prey consumed. These differences cannot be explained by the different body sizes of the predators. The key, the team says, is understanding the differences in muscle performance.
"High energy prey tend to be more mobile, and require their predators to spend more energy to catch them," says Trites. "The two have co-evolved."
The team says that this research will help better assess the impact of resource changes to marine mammals.
"Species with high energy needs are more sensitive to depletion of their primary prey," says Jerome Spitz, a post-doctoral fellow at ULR in France, who completed the research while a visiting scholar at UBC. "It is no longer a question of how much food do whales and dolphins need, but whether they are able to get the right kinds of food to survive."