However, when they began finding small patches of prey at certain depths and of sufficient density, the predators were there. And though the scientists know why feeding efficiency they aren't sure how.
"To be honest, we aren't really sure how these predators which may travel many miles locate the densest aggregations at depths well below the surface and often at night," said Scott Heppell, a fisheries ecologist at Oregon State University and co-author on the PLOS ONE paper. "You wouldn't think murres and fur seals would have that much in common, but in this case they do."
"In a way, they're looking for the same thing that commercial fishing fleets look for high-quality prey in aggregations dense enough to be economical," added Heppell, an assistant professor of fisheries and wildlife at OSU.
Benoit-Bird likened the predator-prey link to locating a box of popcorn in a darkened movie theater. You may have to search for it, she noted, but if you find the popcorn box, the payoff will be much more significant than what you might get by stumbling upon individual kernels in the dark that are spread throughout the theater even though the number of kernels is the same.
That payoff is particularly meaningful for nurturing young, the researchers point out. During their two-year study, the research group tagged and observed female fur seals from St. Paul Island and Bogoslof Island as they swam hundreds of kilometers over a period of 1-2 weeks to gorge on nutrient-rich pollock then return to their homes to nurse pups.
They also tagged and observed adult murres an
|Contact: Kelly Benoit-Bird|
Oregon State University