Scientists will tackle the mysteries of Bering Sea sharks and the decline of northern fur seals with studies funded by the Pollock Conservation Cooperative Research Center at the University of Alaska Fairbanks.
The center, underwritten largely by the pollock fishing industry but supervised by the UAF School of Fisheries and Ocean Sciences, awarded $300,000 in new grants for research into marine life off Alaska’s vast coast.
In pursuit of abundant walleye pollock in the Bering Sea, fishermen inadvertently catch the groundfish’s predators in the same trawls: salmon sharks and sleeper sharks. This bycatch ranges between 400 and 1,400 metric tons per season.
Almost nothing is known about the ecology of these top fish predators, nor whether their population can sustain such losses.
- Shark Bait
- Salmon sharks
- Sleeper sharks
- Shark studies in the Gulf
Salmon sharks — fast, blue-backed endotherms in the same family as Mako and Great Whites — roam Alaska waters during summer in a mysterious annual cycle. A large congregation of young females converge on Prince William Sound and Kenai Fjords areas to feast on summer salmon, for instance. But biologists know little about the behavior or numbers of other adults.
Sleeper sharks — stealthy, smooth-swimming behemoths once mistakenly thought to be sluggish — often travel just below the reach of light and seize their prey whole in immense mouths.
Led by UAF scientist Bob Foy, the shark project will compile existing data and then send biologists out with pollock catcher-processors into the Bering Sea to gather new information about shark demographics, health and ecology.
“Considerable support has been offered by the pollock industry, in particular by the At-Sea Processors, to adequately assess the potential impacts of shark bycatch so that informed mitigation efforts can be implemented,” Foy wrote in his abstract.
Along with investigating shark ecology, other projects will investigate the ecology and dispersal of Pacific Ocean perch — possibly the most abundant rockfish in Alaskan waters of the North Pacific. UAF biologists A.J. Gharrett and T.J. Quinn II will look at genetics, dispersal and harvest. Pacific Ocean perch can live almost 100 years, yet start out their lives as tiny larva free-floating on the current.
UPDATE: A study led by UAF oceanographer Alan Springer and graduate student Alison Banks will analyze what’s known (and unknown) about the alarming decline of northern fur seals in the Pribilof Islands. Along with Steller sea lions, harbor seals, sea otters and a number of bird species, fur seals numbers have been sliding downward since the 1970s for reasons that biologists cannot pin down.
Fur seal mom with pup
Credit: Doug O’Harra
The remaining top hypotheses focus on commercial fishing, regional shifts in climate reducing food for seals, and predation by killer whales, according to the abstract. To sort out what should be done next, Springer and Banks will analyze fur seal ecology and life history — where they reproduce and raise pups for four months in the Bering Sea, and where the female and juveniles migrate for eight months in the North Pacific.
“We will compare fur seal ecology to that of Steller sea lions, harbor seals and sea otters in the North Pacific to help evaluate which factors may be important in the fur seal decline on the Pribilof Islands,” they wrote. “Such a review will enable us to make recommendations about hypotheses and questions that need further research.”
Other funded projects will investigate the ecology of pollock and continue to operate a training program for seafood marketing and processing in Western Alaska.
The pollock research center was founded in 2000 with a grant from the Pollock
Conservation Cooperative, a group of pollock fishing companies affiliated with the At-Sea Processors Association. The group has spent more than $7.4 million to fund at least 40 research projects.
Last year, pollock conservation center projects included a study of how fishermen interacted with Steller sea lions, partly investigating the possibility that shootings or harassment in past decades might have contributed to the 80 percent decline in the population. Other scientists looked into Kachemak Bay kelp forest habitat and genetics of chum salmon.