KODIAK -- Alaska fish can now claim another "best" on the health front -- it is the easiest protein on your tummy.

That is the conclusion of the first comparative study ever 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 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 of Alaska's cold-water fish is that they provide 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."

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 percent 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 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 Andrew Trites at the University of British Columbia, who penned the pollock junk food hypothesis over a decade ago. Trites' premise is that the North Pacific warmed in the late 1970s, 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.

THE TEMPERATURE FACTOR

Results from three seasons of fishing tests indicate that temperature data might be used to reduce the accidental catch of king salmon by the Bering Sea pollock fleet.

A new study by John Gauvin of the Marine Conservation Alliance Foundation and Jim Ianelli of the Alaska Fisheries Science Center found that pollock primarily stayed in water within a 2-4 degrees Celsius range, and that king salmon bycatch was generally higher in those water temperatures. (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.

Find the full report at www.mcafoundation.org.