Arrowtooth Flounder

The arrowtooth flounder is an interesting character in our cast of Alaska commercial fishes. It has had a history of playing the role of good cop-bad cop, or rather, good fish-bad fish. Individual arrowtooth flounders can grow to a large size and collectively, they are often very abundant, especially in the Gulf of Alaska. Their flesh is firm and white, and they have often been caught incidental to other harvests but they were discarded. They simply have not been directly valuable as a commercially-harvested fish.

It seems that they got their bad fish reputation because their flesh contains a particular enzyme that causes the flesh to degrade and soften during cooking. Although the flavor and nutritional value do not change, the appearance and feel of the flesh becomes unacceptable and, therefore, not marketable.

Because the fish had little economic value, not much scientific information about the arrowtooth flounder has been assembled. In Alaska, these fish are found from the eastern Bering Sea through the Aleutian Islands and along the coast to southeast Alaska. In addition, they range south to central California.

Arrowtooth flounder are found at depths of approximately 150 to 2,900 feet and they move seasonally between deep water in winter for spawning and in shallow water for summer feeding. They are usually found over soft bottom materials. Peak of spawning is in fall and winter. Eggs are slightly buoyant and drift with the currents. After hatching the larval period is at least a month long. Young fish occupy shallower waters than adults.

Arrowtooth flounders become mature at about five years of age and after maturity, females grow faster and bigger than males. Maximum size for males is about 30 inches and the maximum size for females is about 33 inches. maximum weight for males is about 4 pounds and, for females, about 7 pounds.

These fish may live for about 25 years, but most that are caught are about 15 years of age. Juvenile arrowtooth flounders eat mostly invertebrates but adults feed mainly on fish and sometimes are cannibalistic. This fish is well equipped as a predator. Their mouth is large and the jaws are filed with long, sharp teeth. Alternatively, arrowtooth flounder are eaten by other fish and Steller sea lions.

Harvest of arrowtooth flounder in Alaska waters in 2011 was about 39,000 tons. Most are harvested by bottom trawling.

And now, the rest of the story. . . the good fish part.

In about 2000, food scientists developed a process to neutralize the enzyme that caused the flesh of the arrowtooth flounder to degrade and become mushy when heated. Processing includes mincing the flesh and mixing it with an enzyme inhibitor.

Much of the arrowtooth flounder harvest is processed to make surimi. Processed surimi is a puree or slurry made from fish flesh that has been pulverized and washed. When heated, it becomes a dense, white, rubbery, tasteless paste. Flavoring, additives, shape, and coloring may be added to produce a final product that may mimic the meat of crab, lobster, and other shellfish. In the United States, the most common product is mock crab (or often, krab) or fish sticks.

Currently, two or three million tons of fish from around the world are processed to make surimi-based products. This amounts to about 2 to 3 per cent of the world fisheries. Most is utilized in Asia.

For a bit more information and an image of the arrowtooth flounder, go to the following web site and click on arrowtooth flounder: http://www.fishwatch.gov/seafood_profiles/index.htm

 

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Bill recently published Fishes of the Last Frontier, Life Histories, Biology, Ecology, and Management of Alaska Fishes and, previously, Letters from Alaska, The Inside to the Outside.