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Fish Factor

Another "best" for Alaska fish


April 10, 2010

Alaska fish can now claim another "best" on the health front - it is the easiest protein on your tummy. That is the finding of the first comparative study ever done on digestibility of America's most popular proteins.

"Most people have assumed that fish is a superior source of protein but no studies have been done to prove it. We wanted to fill that gap by studying the compositional and digestibility differences between the big protein sources - beef, pork, chicken and fish," said Dr. Scott Smiley at the University of Alaska's Fishery Industrial Technology Center in Kodiak.

Alaska pollock was by far the most digestible protein, followed by Alaska salmon.

"The fish came way out on top. Interestingly, chicken was the least digestible," Smiley said.

They all are high quality proteins, Smiley added, but the main distinction with cold water fish from Alaska is that it also provides omega 3 fatty acids.

"Those are incredibly healthful for humans," Smiley said. "And omegas are tremendously potent in terms of undoing the damage that saturated fatty acids associated with red meats have done over the years because of our diet."

Smiley said the Alaska scientists were "thrilled" at the study results.

"We suspected this would be the case, but it is always good to see it validated through testing. And we tested it 'seven ways through Sunday' here in both laboratory and field tests. This is the kind of science that can float all boats and hopefully will make more people look to fish as their protein source."

FITC scientists collaborated on the study with researchers at the University of Illinois/Urbana. Results are published in the Journal of Animal Science.

Sea lions love junk food

New research backs up earlier findings that pollock is junk food for sea lions. As the debate continues over the cause of sea lion declines throughout Alaska's westward regions, diet is still a focal point. Bering Sea fishing fleets have taken the hit for removing too much pollock from the sea lions' dinner plates. But recent feeding studies show that particular fish does not provide enough body energy for sea lions, no matter how much they eat.

Scientists from the Marine Mammal Research Consortium in British Columbia tweaked the diets of eight female sea lions for one month in the summer and in the winter. Each received 80 % of their normal energy food intake - but one group was given herring and the other was fed pollock. The pollock group ate almost twice as much of their daily intake as normal.

"We wanted to see how they would decide to partition their energy budget when they don't get enough energy for everything," said lead researcher Tiphaine Jenniard du Dot.

Both groups of animals lost the same amount of weight during the feeding trials, but from different parts of their bodies. The sea lions that ate pollock lost muscle mass, which over time could cause them to lose organ functions. The animals that ate the oilier herring adjusted better to the loss of energy from their food.

"So it seems that if they are on a bad diet, or a low quality diet, they may not be able to adjust to the environment as well," Jenniard du Dot told KUCB in Unalaska.

She added that it appears different foods trigger different hormonal reactions, and the systems of the sea lions eating pollock are confused - their bellies are full but they don't get enough energy to function normally. Scat samples collected during summer surveys show sea lions are eating low energy pollock because that is what is mostly available.

The findings support those of Dr. Andrew Trites at the University of British Columbia who over a decade ago penned the pollock junk food hypotheses. Trite's premise is that the North Pacific warmed in the late 1970's causing cod and pollock to thrive in Westward regions, while herring and other oily fish dropped off. He contends that the higher oil and calorie content of the formerly abundant prey offered better nutrition, so females more quickly weaned their pups and bred again.

More recently, female sea lions who could give birth every year instead keep nursing pups for up to three years because of decreases in energy. Predation by killer whales has a more pronounced limiting effect when the sea lion population already is down.

Temperature and fish takes

Results from three seasons of fishing tests indicate that temperature data might be used to reduce Chinook salmon bycatch in Bering Sea pollock fisheries.

A new study by John Gauvin of the Marine Conservation Alliance Foundation and Jim Ianelli of the AK Fisheries Science Center found that pollock were found to primarily stay within the two to four degrees Celsius range, and within that, king salmon bycatch was generally higher. (Chum salmon bycatch appeared to have a similar but weaker relationship with temperature.)

The researchers believe temperature and depth data collections may be used by the fleet to avoid high bycatch zones.

"If collections of fine-scale temperature data on Alaska fishing vessels can be continued in the future to obtain a longer time series, as well as extending this effort to the other fishing grounds, the potential clearly exists for a new and effective tool for reducing salmon and other bycatch in Alaska's groundfish fisheries," the study said. Alaska pollock is the largest U.S. fishery, accounting for more than one-third of total U.S. landings. Find the full report at .

Biggest fish buzz

The issue that is worrying most industry stakeholders in Alaska is marine spatial planning, or "ocean zoning" - and that the calls might be made outside the realm of regional fishery councils. That was the talk in the halls at the North Pacific Council meeting underway at the Anchorage Hilton.

The Interagency Ocean Policy Task Force created last June by the White House calls it a "more comprehensive approach to protecting and restoring the health of U.S. oceans and coasts." The new spatial approach uses chart lines on huge swaths of ocean to define strict zones for all users: shipping lanes, oil and gas development, fiber optic cables, fishing areas and other marine activities.

"It is already used in several other countries, and in the U.S. it has been done on a state by state initiative," said Arne Fuglvog, fisheries aide to Senator Lisa Murkowski.

"This is something that all of Alaska's fisheries can get behind," said fisheries consultant Linda Kozak of Kodiak. "There might be disagreement on other issues, but zoning our oceans affects us all."

This weekly column focusing on Alaska's seafood industry began in 1991, and it now appears in over 20 newspapers and web sites. A spin off - Fish Radio - airs weekdays on 30 radio stations in Alaska. The goal of both is to make all people aware of the economic and social importance of Alaska's fishing industry to our state, the nation and the world. Happy New Year and thanks for your continued support of fishing news!

Laine can be reached at msfish[AT]


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Stories In The News
Ketchikan, Alaska

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