Rock Sole

About The Species

U.S. wild-caught rock sole is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.

Status

• There are two species of rock sole, northern rock sole and southern rock sole.
• Northern rock sole are found in the Bering Sea/Aleutian Islands, and according to a 2018 stock assessment are not overfished and are not subject to overfishing.
• Both the northern and southern species of rock sole are found in the Gulf of Alaska, and according to a 2018 stock assessment are not overfished and are not subject to overfishing.
• On the West Coast, rock sole make up only a small percentage of groundfish harvests. Scientists do not formally assess this species so the population status is unknown.
• Rock sole are part of the “other flatfish” complex on the West Coast, and are not subject to overfishing based on 2016 catch data.

Appearance

• Rock sole are a flatfish with both eyes located on the right side of their head.
• Northern rock sole’s underside is creamy white, whereas southern rock sole’s underside is white with glossy highlights.
• Rock sole are sometimes called roughback because of the rough scales on their backs. 

Biology

• Rock sole grow up to 2 feet long and can live for more than 20 years.
• They are able to reproduce when they reach 4 to 7 years old. 
• Northern rock sole spawn in midwinter and spring, and southern rock sole spawn in the summer.   
• Females lay eggs near the ocean bottom, and the eggs stick wherever they land. Eggs hatch between 6 and 25 days later, depending on water temperature.
• Larval rock sole eat plankton and algae.
• Early juveniles eat zooplankton, and late juvenile and adults prey on bivalves, worms, amphipods, mollusks, and crustaceans. 
• Larger fishes, including rock sole, feed on larval and juvenile rock sole.
• Sharks, marine mammals, and larger fishes prey on adults.
• Rock sole’s coloring and movements on the sea floor often confuse predators. 

Where They Live

• Northern rock sole are found from Puget Sound through the Bering Sea and Aleutian Islands to the Kuril Islands (north of Japan).
• Southern rock sole are found from the southeast Bering Sea to Baja 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 set an annual catch limit for rock sole.
  • In the Bering Sea/Aleutian Islands a percentage of the annual catch limit 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 a 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 two 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 rock sole is harvested incidentally in fisheries off the West Coast.
  • Rock sole is included in the groundfish fishery management plan, but it is not assessed or directly managed.