Flathead Sole
Flathead Sole
Hippoglossoides elassodon
Also Known As
Sole, Flounder, Flathead flounder, Halibut-like flounder
Quick Facts
Region
Alaska,
West Coast
About the Species
U.S. wild-caught flathead sole is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.
Population
Gulf of Alaska and Bering Sea/Aleutian Islands flathead sole are not overfished.
Fishing Rate
Not subject to overfishing.
Habitat Impacts
Area closures and gear restrictions protect habitats affected by bottom trawls used to harvest flathead sole.
Bycatch
Regulations are in place to minimize bycatch.
Population Status
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There are three stocks of flathead sole: a Gulf of Alaska stock, one stock contained in the Bering Sea/Aleutian Islands Flathead Sole Complex, and one stock contained in the Other Flatfish Complex along the Pacific coast. According to the most recent stock assessments:
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The Gulf of Alaska coast stock is not overfished (2017 stock assessment) and not subject to overfishing based on 2021 catch data. Summary stock assessment information can be found on Stock SMART.
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Flathead sole is managed as part of the Bering Sea / Aleutian Islands Flathead Sole Complex, is the primary species in the complex and has been assessed. The complex is not overfished based on the assessment of flathead sole (2020 stock assessment) and not subject to overfishing based on 2021 catch data. Summary stock assessment information can be found on Stock SMART.
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Flathead sole is managed as part of the Other Flatfish Complex and has not been assessed so the population status is unknown. This complex is not subject to overfishing based on 2020 catch data.
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Appearance
- Flathead sole have an oval-shaped, compressed body.
- They are flatfish, with both of their eyes located on the right side of their head.
- Their upper side is dark olive brown to reddish gray-brown, sometimes with dusky blotches, and their underside is white.
- Their dorsal and anal fins have dusky blotches.
Biology
- Flathead sole grow up to 1.8 feet and can live at least 34 years.
- They are able to reproduce at 2 to 3 years old in the southern part of their range, but not until 6 years old in the northern part.
- Flathead sole spawn from February through April in deeper waters on the continental shelf.
- Depending on their size, females release 72,000 to 600,000 eggs. Eggs are large and are fertilized externally.
- Eggs hatch in 9 to 20 days, depending on water temperature.
- Flathead sole generally feed on bottom-dwelling invertebrates such as crustaceans, mollusks, and brittle stars, as well as fish and squid.
- Pacific cod, halibut, Alaska pollock, and arrowtooth flounder prey on flathead sole.
Where They Live
Range
- Flathead sole are found from Alaska south along the west coast of North America to northern California.
Habitat
- Young flathead sole live in shallow estuaries, bays, and nearshore coastal areas along the Pacific coast.
- Adults live on mixed muddy and sandy ocean habitats in depths less than 1,000 feet.
- They migrate from winter spawning grounds along the outer continental shelf to feeding grounds in shallower water in the spring.
Fishery Management
- NOAA Fisheries and the North Pacific Fishery Management Council manage this fishery in Alaska.
- Managed under the Fishery Management Plans for Groundfish of the Bering Sea and Aleutian Islands and Gulf of Alaska:
- Fishermen must have a permit to participate in the fishery, and the number of available permits is limited to control the amount of fishing.
- Managers determine how much flathead sole can be caught each year based on assessments conducted in the Bering Sea/Aleutian Islands and Gulf of Alaska.
- In the Bering Sea/Aleutian Islands a percentage of the allowable catch is allocated to the community development quota program, which benefits fishery-dependent communities in Western Alaska. The rest is allocated under a catch share program to the trawl catcher/processor sector based on historic harvest and future harvest needs to improve retention and utilization of fishery resources by the trawl fleet.
- In the Gulf of Alaska, total allowable catch is allocated by regulatory area (western, central, and 2 sub-areas of the eastern Gulf of Alaska).
- Catch is monitored through record keeping, reporting requirements, and observer monitoring.
- NOAA Fisheries and the Pacific Fishery Management Council manage this fishery on the West Coast.
- Managed under the Pacific Coast Groundfish Fishery Management Plan:
- Only a small amount of flathead sole is harvested incidentally in fisheries off the West Coast.
- Flathead sole is included in the groundfish fishery management plan, but it is not assessed or directly managed.
Harvest
- In 2021, commercial landings of flathead sole totaled 22 million pounds and were valued at approximately $3 million dollars, according to the NOAA Fisheries commercial fishing landings database.
- Almost all commercial harvest of flathead sole comes from Alaska, mainly the Bering Sea and Aleutian Islands.
- Gear types, habitat impacts, and bycatch:
- Flathead sole are primarily caught with bottom trawls, and some are caught with pelagic trawls.
- Gulf of Alaska and Bering Sea/Aleutian Islands fishermen use modified trawl gear that reduces the impact of trawling on animals living on the sea floor, including crabs.
- Halibut, salmon, and crab are incidentally caught in the groundfish fishery in Alaska.
- There are limits on how much halibut, herring, and crab can be caught incidentally. If this limit is reached, an area or the entire fishery is closed for the remainder of the season.
- In Alaska and on the West Coast, NOAA Fisheries and the regional fishery management councils have implemented large closed areas to protect sensitive rocky, cold-water coral and sponge habitats from bottom trawls.
- Recreational fishermen may fish for flathead sole:
- Only hook-and-line and spear gear is allowed.
- Bag limits on the number of fish that can be caught vary by state.
Scientific Classification
- Flathead sole are found from Alaska south along the west coast of North America to northern California.
- Young flathead sole live in shallow estuaries, bays, and nearshore coastal areas along the Pacific coast.
- Adults live on mixed muddy and sandy ocean habitats in depths less than 1,000 feet.
- They migrate from winter spawning grounds along the outer continental shelf to feeding grounds in shallower water in the spring.
Fishery Management
- NOAA Fisheries and the North Pacific Fishery Management Council manage this fishery in Alaska.
- Managed under the Fishery Management Plans for Groundfish of the Bering Sea and Aleutian Islands and Gulf of Alaska:
- Fishermen must have a permit to participate in the fishery, and the number of available permits is limited to control the amount of fishing.
- Managers determine how much flathead sole can be caught each year based on assessments conducted in the Bering Sea/Aleutian Islands and Gulf of Alaska.
- In the Bering Sea/Aleutian Islands a percentage of the allowable catch is allocated to the community development quota program, which benefits fishery-dependent communities in Western Alaska. The rest is allocated under a catch share program to the trawl catcher/processor sector based on historic harvest and future harvest needs to improve retention and utilization of fishery resources by the trawl fleet.
- In the Gulf of Alaska, total allowable catch is allocated by regulatory area (western, central, and 2 sub-areas of the eastern Gulf of Alaska).
- Catch is monitored through record keeping, reporting requirements, and observer monitoring.
- NOAA Fisheries and the Pacific Fishery Management Council manage this fishery on the West Coast.
- Managed under the Pacific Coast Groundfish Fishery Management Plan:
- Only a small amount of flathead sole is harvested incidentally in fisheries off the West Coast.
- Flathead sole is included in the groundfish fishery management plan, but it is not assessed or directly managed.
Harvest
- In 2021, commercial landings of flathead sole totaled 22 million pounds and were valued at approximately $3 million dollars, according to the NOAA Fisheries commercial fishing landings database.
- Almost all commercial harvest of flathead sole comes from Alaska, mainly the Bering Sea and Aleutian Islands.
- Gear types, habitat impacts, and bycatch:
- Flathead sole are primarily caught with bottom trawls, and some are caught with pelagic trawls.
- Gulf of Alaska and Bering Sea/Aleutian Islands fishermen use modified trawl gear that reduces the impact of trawling on animals living on the sea floor, including crabs.
- Halibut, salmon, and crab are incidentally caught in the groundfish fishery in Alaska.
- There are limits on how much halibut, herring, and crab can be caught incidentally. If this limit is reached, an area or the entire fishery is closed for the remainder of the season.
- In Alaska and on the West Coast, NOAA Fisheries and the regional fishery management councils have implemented large closed areas to protect sensitive rocky, cold-water coral and sponge habitats from bottom trawls.
- Recreational fishermen may fish for flathead sole:
- Only hook-and-line and spear gear is allowed.
- Bag limits on the number of fish that can be caught vary by state.
Scientific Classification
| Kingdom | Animalia | Phylum | Chordata | Class | Actinopterygii | Order | Pleuronectiformes | Family | Pleuronectidae | Genus | Hippoglossoides | Species | elassodon |
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Featured News
Alaska pollock. Credit: NOAA Fisheries.
Related Species
Seafood Facts
Is Flathead Sole Sustainable?
U.S. wild-caught flathead sole is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.
Availability
Year-round.
Source
U.S. wild-caught from Alaska, and sometimes Oregon.
Taste
Mild and delicate flavor.
Texture
Firm and thick fillets.
Color
White.
Health Benefits
Flathead sole is an excellent source of low-fat protein as well as calcium and vitamins.
Nutrition Facts
Servings: 1; Serving Weight: 100 g (raw); Calories: 91 ; Protein: 18.84 g ; Total Fat: 1.19 g; Total Saturated Fatty Acids: 0.283 g; Carbohydrate: 0 g; Total Sugars: 0 g; Total Dietary Fiber: 0 g; Cholesterol: 48 mg; Selenium: 32.7 mcg; Sodium: 81 mgSeafood News
Seafood stall at Tuna Harbor Dockside Market in San Diego. Photo credit: Ron Batcher
NOAA Administrator, Dr. Richard Spinrad, and NOAA Fisheries Assistant Administrator, Janet Coit, with representatives from the Intertribal Agriculture Council at Seafood Expo North America 2023 in Boston. Credit: NOAA Fisheries.