( eason was marked by unusually warm wate...)High-tech tags on marine animals yield valuable data for biologists and oceanographers

"The sea lions disappeared from Monterey Bay, as did the bait fish. We were only able to tag three male sea lions that year, and they went much farther off shore than usual to find food. They've always been described as a strictly coastal species, but they went as far out as 300 miles from the coast," he said.

At the same time, Costa's group was also tracking the movements of elephant seals and albatrosses. These species, which typically forage across a broad area of the North Pacific Ocean, showed little change in their movement patterns in 2004 and 2005. As platforms for ocean sensors, northern elephant seals and California sea lions can provide complementary information because of their different foraging patterns, Costa said.

"Elephant seals provide incredible coverage of the North Pacific, while the sea lions are good along the coastal upwelling region," he said.

Similar complementarity is provided by southern elephant seals and crabeater seals in the Southern Ocean. Costa led a study of crabeater seals during the Antarctic winters of 2001 and 2002, tagging 34 seals and tracking their foraging patterns. Crabeater seals are specialized for feeding on Antarctic krill and forage along the continental shelf of Antarctica at the edge of the ice pack.

Southern elephant seals, in contrast, forage widely in the offshore waters. The SEaOS project led by SMRU's Fedak is deploying electronic tags on elephant seals at three locations in the Southern Ocean. The oceanographic data gathered by the seals on their foraging trips from these different locations provide circumpolar coverage of the Southern Ocean, Costa said.

"We are collecting a tremendous amount of data in this area of the world and working with physical oceanographers to incorporate these data into oceanographic m
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Source:University of California - Santa Cruz