Marine Mammals Need To Eat Right To Survive
November 23, 2012

Varied Diets Of Dolphins And Whales Key To Their Survival

April Flowers for - 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.

A new study from the University of British Columbia (UBC) and the University of La Rochelle (ULR), published online in the journal PLOS ONE, is the first to show that the survival of whales and dolphins depends on the quality of their diets. These findings could play an important role in conservation efforts.

"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."