Arrowtooth Flounder

Arrowtooth flounder

Atheresthes stomias

ALSO KNOWN AS:

    Flounder, Arrowtooth Halibut, Turbot, Paltus

SOURCE:

    U.S. wild-caught from Alaska to Oregon
 

STATUS

  • POPULATION
  • FISHING RATE
  • HABITAT IMPACTS
  • BYCATCH
 

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OVERVIEW

Arrowtooth Flounder

Researcher separating arrowtooth flounder from Alaska pollock during a trawl survey of the Gulf of Alaska.

LAUNCH GALLERY

Arrowtooth flounder are caught in flatfish fisheries off the West Coast and Alaska. From the 1950s to the 1970s, they were harvested in large, unselective flatfish fisheries that supplied food for mink ranching operations in the Pacific Northwest.

A targeted fishery for arrowtooth flounder developed in the late 1970s but dwindled due to low market demand for the fish due to its poor-quality flesh—an enzyme found in the fish rapidly degrades the flesh when it’s heated, making it mushy when cooked. In the past, this breakdown limited efforts to develop a market for this underused, abundant fish. Recently, researchers have found several food additives that successfully stop this breakdown, increasing the marketability of arrowtooth flounder products as inexpensive flounder. To make it more marketable, arrowtooth flounder is often sold on the West Coast as turbot, although it is not related to the true turbot (Psetta maxima), a highly valued fish caught off Europe. Arrowtooth flounder is also increasingly sold for fishmeal and surimi (imitation crab).

Because of these recent market improvements, a targeted fishery for arrowtooth flounder has developed off Alaska. Alaska supplies most of the arrowtooth flounder on the market, although harvests here are still limited by market demand as well as halibut bycatch limits.

Looking Ahead

Attempts have been made to expand the production of arrowtooth flounder as surimi, the processed fish used to make products such as imitation crab. While the economic feasibility of this is still uncertain, the current worldwide surimi supply shortage caused by reductions in the U.S. pollock catch may make the abundant arrowtooth flounder an increasingly attractive alternative for producing surimi.

 
 
 

LOCATION & HABITAT

Arrowtooth flounder are found from Northern California through the Bering Sea. Their eggs and larvae are found in the water column, generally at depths greater than 400 meters; juveniles and adults live on the ocean floor. They’re most common on sand or sandy gravel habitat and occasionally over low-relief rock-sponge bottoms.

During the summer, arrowtooth flounder feed in shallow water on the continental shelf. They migrate to deep water over the continental slope to spawn in the winter.

 
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BIOLOGY

Arrowtooth flounder grow slowly and can live  up to 27 years. Males can reach 2 feet in length; females grow a bit larger, up to almost 3 feet. Males sexually mature when they reach 3 to 7 years old; females are able to reproduce a little later when they reach 4 to 8 years old. Spawning season varies by location – from late fall through early spring off the West Coast, during spring and summer in the Gulf of Alaska, and during fall and winter off the coast of Alaska. Arrowtooth flounder spawn multiple times during a spawning season. They release eggs that are fertilized externally. Arrowtooth flounder hatch in deep water (below 400 meters) and rise up the water column with development, then settle to the bottom during the summer and fall.

Arrowtooth larvae eat copepods, a type of small crustacean. Juveniles and adults feed on crustaceans (mainly ocean pink shrimp and krill) and fish (mainly cod, herring, and pollock). A variety of fish and marine mammals prey on arrowtooth flounder, including skates, sharks, shortspine thornyhead, halibut, orcas, other toothed whales, and harbor seals. In the Gulf of Alaska, arrowtooth flounder are an important part of the diet of Steller sea lions.

 
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PHYSICAL DESCRIPTION

Arrowtooth flounder are a relatively large, brownish colored flatfish with a large mouth. They’re members of the family Pleuronectidae, the right-eyed flounders- both eyes on their right side and lie on the ocean floor on their left side.

 
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OVERVIEW

Scientists at NOAA’s Alaska and Northwest Fisheries Science Centers conduct trawl surveys to estimate the abundance of arrowtooth flounder in Alaska and West Coast waters.

 
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POPULATION STATUS

Arrowtooth flounder stocks are well above their target population levels in all areas (West Coast, Gulf of Alaska, and Bering Sea/Aleutian Islands). The Gulf of Alaska and Bering Sea/Aleutian Islands stocks were last assessed in 2013.

 
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Harvesting arrowtooth flounder

Fishermen mainly use bottom trawl gear, including specialized flatfish trawls, to catch arrowtooth flounder. Bottom trawlers tow a funnel-shaped net on or near the ocean floor, collecting fish in the narrow part of the net (the cod-end). Trawl doors keep the net open, and a weighted rope (called a footrope) keeps the net close to the floor. The trawl doors and footrope of the net can contact and impact the ocean floor. In general, arrowtooth flounder live on sandy or sand/gravel habitats; these soft bottom habitats are usually more resilient than other habitats to trawling impacts.

In Alaska, NOAA Fisheries scientists and the flatfish fishing industry collaborated to develop changes to fishing gear that would reduce effects of flatfish trawling on seafloor habitats of the Central Gulf of Alaska and eastern Bering Sea shelf. The modified gear they developed – Bering Sea flatfish gear – not only reduced impacts to sea floor habitat and the animals living there but also reduced the fishery’s impacts on crabs. In the Central Gulf of Alaska and Bering Sea and Aleutian Islands area, flatfish fishermen are now required to use this modified fishing gear. Halibut are sometimes incidentally caught in this fishery, but there is a limit on the number of halibut that can be incidentally caught in the fishery. When this limit is reached, the directed fishery is closed.

Off the West Coast, fishermen catch arrowtooth flounder with a selective flatfish trawl, a design that substantially reduces catches of rockfish species while more efficiently catching the targeted flatfish species. Some rockfish, including canary rockfish (an overfished groundfish listed as threatened under the Endangered Species Act), are still unintentionally caught, but management caps the amount of rockfish that can be incidentally caught in the fishery. To protect sensitive fish habitat off the West Coast, gear restrictions limit where flatfish fishermen can fish.

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Management

Who’s in charge? NOAA Fisheries and the North Pacific and Pacific Fishery Management Councils.

Current management:

Alaska: Gulf of Alaska and Bering Sea and Aleutian Islands Groundfish Fishery Management Plans Although arrowtooth flounder are not currently a major commercial seafood species in Alaska fisheries, the species has been included in these fishery management plans because of their importance to the ecosystem (it’s a very abundant flatfish and an important part of the food chain as both predator and prey) and growing commercial interest. There is a limit on the total amount of arrowtooth flounder that can be harvested each year; however, annual harvests have consistently been below this level.

West Coast: Groundfish Fishery Management Plan disclaimer. (Arrowtooth flounder are often caught along with several different groundfish species; they are managed with 90 other species that also live on or near the bottom.)

  • General regulations include groundfish harvest levels and fishing restrictions (trip limits, season lengths, gear restrictions such as minimum mesh size for nets, etc.). NOAA Fisheries publishes these regulations every other year, before the start of the fishing year on January 1. NOAA Fisheries may amend these regulations in-season to correct mistakes or revise management measures according to recommendations from the Pacific Fishery Management Council.
  • A variety of closed areas affect both West Coast groundfish fisheries and fisheries that may take groundfish incidentally. Areas are closed to reduce bycatch of overfished groundfish species and protect groundfish habitat. Managers use a vessel monitoring program to monitor fishing activity and ensure vessels are complying with these closures.
  • All vessels fishing for groundfish off Washington, Oregon, and California must have a federal limited entry permit. With a finite number of permits available (about 400), this program controls the size of the groundfish fishing fleet by limiting the number of fishing vessels and limiting vessel length.
  • As of January 2011, the West Coast groundfish trawl fishery is now managed under a trawl rationalization catch share program. Under this new program, managers establish annual catch limits based on the health of each fish stock. They then allocate a share of this catch limit to individual fishermen or groups of fishermen. These fishermen can decide how and when to catch their share – preferably when weather, markets, and business conditions are most favorable, allowing the fishery the flexibility to be more environmentally responsible, safer, more efficient, and more valuable. Observers monitor 100 percent of the fishing trips, which helps reduce bycatch and provide better data for future stock assessments.
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Annual Harvest

In 2012, more than 81 million pounds of arrowtooth flounder were harvested from U.S. waters. Although arrowtooth flounder are a low-value fish, fishermen have recently been retaining more of the arrowtooth they catch – up to about 80 percent in Alaska. Catches have been higher in recent years because arrowtooth flounder are more abundant, resulting in higher incidental catch in other fisheries, in addition to increased marketing efforts for arrowtooth fish meal and surimi. In 2012, more than 94 percent of all arrowtooth landed in U.S. fisheries came from Alaska. The remainder of the catch was landed off the U.S. West Coast from Washington to California.

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Economy

Arrowtooth flounder harvested during 2012 was worth more than $9 million. 

Several food-grade additives have been successfully used to inhibit the enzymatic breakdown of arrowtooth’s flesh when heated. These discoveries have enabled a targeted fishery in the Kodiak Island area for a number of marketable products. Most arrowtooth flounder are processed as headed and gutted and sent to China for re-processing. The primary product for arrowtooth flounder is the frill, the thin muscle of the dorsal fin which is located on the side of the fish used for engawa (a premium sushi usually made from halibut or Greenland turbot, but more affordable using arrowtooth flounder). A large portion of the arrowtooth flounder exported to China are processed into fillets and re-imported to U.S. markets as inexpensive flounder. Some arrowtooth flounder processed in Japan are also sold as fillets in the Japanese market and have even recently shown up in European markets.

From 2007 through 2011, the worldwide surimi supply shortage caused by reductions in the U.S. pollock quota expanded the production of arrowtooth flounder into surimi. Surimi is the processed fish used to make imitation crab. However, arrowtooth surimi production declined again with the increase of pollock landings in 2011.

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OVERVIEW

Arrowtooth flounder is a delicate white fish with a mild, sweet flavor. It’s commonly marketed for engawa, a type of sushi, and as fillets.

 
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SEASONAL AVAILABILITY

Year-round.

 
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NUTRITION

Flounder is a good, low-fat source of B vitamins and an excellent source of niacin.

Servings 1
Serving Weight 100 g (raw)
Calories 91
Protein 18.84 g
Fat, total 1.19 g
Saturated fatty acids, total 0.283 g
Carbohydrate 0 g
Sugars, total 0 g
Fiber, total dietary 0 g
Cholesterol 48 mg
Selenium 32.7 mcg
Sodium 81 mg

Arrowtooth Flounder Table of Nutrition

 
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RECIPES

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