For most animals, the priority is to find enough quality food while avoiding predators. Steller sea lions are no exception. Understanding how they achieve these activities is fundamental to figuring out why some sea lion populations are fairing better than others.

Sea lion researchers have learned a great deal over the past decade about what sea lions eat, approximately where they forage and who their potential predators are. What is not known is how sea lions find and catch their prey and how they avoid appearing on the killer whale menu. To answer these questions, Consortium Researchers are spending a winter on the water with foraging sea lions.

The “Behaviour@Sea Project”, led by UBC Researchers Dr Ben Wilson and Dr Mary-Anne Lea, started this fall in southeast Alaska. In collaboration with the Alaska Department of Fish and Game, small acoustic and radio transmitters were glued to the fur of a few juvenile sea lions. This allows the Consortium team to follow the sea lions at sea, whether it is day or night, windy or calm.

“This is an entirely new approach”, says Ben Wilson. “Previously we’ve had to infer what Steller sea lions might be doing at sea from erratic satellite transmitter fixes and from what they bring back to shore in their digestive systems. By actually following the sea lions we’ll be able to put these patterns into a real context.”

Questions being addressed include: do sea lions feed in favorite spots or do they follow their noses and decide the route as they go? If so, what factors influence the path they take? Do they devote time and effort to every fish school they encounter or are they picky and ignore ones that might be too deep or dispersed? And if so, what is too deep and too dispersed?”

But the prospect of spending the winter at sea in Alaska is not something that most people might relish. “Lynn Canal can be a wild and treacherous body of water at this time of year” says Mary-Anne Lea “but it’s a very interesting site in terms of sea lion behaviour and what is already known about the fish there.” The Consortium Researchers are coordinating the sea lion foraging study with the fish abundance studies carried out by Dr Michael Sigler and his colleagues at the NMFS Auke Bay Laboratory. “We’re excited about this joint study” says Lea, – “it’s an opportunity to tie together detailed information on both the behaviour and distribution of predators and their prey.”

You can keep up to date with the findings of the project by visiting the Behaviour@Sea website.

17 November 2003

note: Research was completed under Marine Mammal Permit number: 7151475