Saildrone Technology Tracks Pursuit of Pollock by Fur Seals

Fisheries researchers using Saildrones surveyed more than 1,700 miles within the fur seal foraging area of the Bering Sea this summer, measuring and locating walleye pollock that are the main food source for northern fur seals.

The unmanned drones are giving the Alaska Fisheries Science Center new insight into foraging habits of female northern fur seals, whose populations have been dwindling since the 1970s, says Carey Kuhn, an ecologist with the center, who has been blogging the project.

The next step will be analyzing all the data from the fur seal tags and devices on the Saildrones, an effort that will take Kuhn and her colleague, fisheries biologist Alex De Robertis, a couple of months to process. Knowing where the pollock and other prey sought by the fur seals in summer months are available may help unravel the mystery of why the seal population continues to decline, she said.

The researchers tagged 30 adult female fur seals at their breeding grounds during the breeding season and in addition to returning to the breeding grounds in the fall to measure the tagged seals, they get diet analysis from scat in the rookeries and fish bones, Kuhn said.

Reduced prey availability is just one hypothesis for the decline of the fur seal population. Before any decisions are made that would affect related management of the pollock fishery, Center researchers need to understand what is going on with the ecology of the fur seals. “Our goal isn’t to make those types of decisions without strong scientific backing,” Kuhn said.

Once the data is compiled it goes to NOAA’s Alaska regional office, which oversees the northern fur seal conservation plan, and it is there that any management decisions are made.