Flathead Sole

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.

Status

• According to the 2017 stock assessment, flathead sole in the Bering Sea/Aleutian Islands are not overfished and are not subject to overfishing.
• According to the 2017 stock assessment, flathead sole in the Gulf of Alaska are not overfished and are not subject to overfishing.
• Flathead sole are quite abundant in Alaska, and populations are well above target levels.
• On the West Coast, flathead sole make up only a small percentage of groundfish harvests. Scientists do not formally assess this species so the population status is unknown.
• Flathead sole are part of the “other flatfish” complex on the West Coast, and are not subject to overfishing based on 2016 catch data.

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

• Flathead sole are found from Alaska south along the west coast of North America to northern California.

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.