What is a Rock Sole?

The rock sole is considered a commercially important edible fish. While rock sole are generally found in the highest concentrations in the waters of the Bering Sea, some species may be found as far south as the coastal waters of Mexico. They generally grow to an adult length of about 24 inches (60 cm), and may live for more than 20 years. Their coloring generally allows them to camouflage themselves against the sea floor, where, as a flatfish, the rock sole generally remains.

These fish can grow very slowly, and can take up to seven years to reach their full adult size. They typically spawn in February and March, and the eggs usually hatch six to 25 days later. While they usually spawn in deep offshore waters, they may prefer to remain in shallow coastal waters for the rest of the year. Rock sole sometimes spawn in shallow waters, and may spawn in sandy, muddy, or rocky areas. These fish often remain in shallow coastal waters as they are maturing, and then begin moving into deeper waters more often as they grow closer to their adult size.

These fish generally feed on worms, crustaceans, mollusks, and smaller fish. Newly hatched rock sole often move about to follow their prey. Juvenile and adult rock sole usually feed on other bottom-dwelling fishes, crustaceans, and mollusks. Their natural predators include sharks, Pacific halibut, Pacific cod, Alaska pollock.

Rock sole are considered flatfish because they usually have both eyes on one side of the head and possess a wide, flat body. The top of this fish is generally mottled and grayish in color, to help it conceal itself against the sea floor. The bottom of the fish is usually pale.

Though once fished to near depletion, the rock sole is today considered a bountiful commercial food fish. Their eggs are considered a delicacy in some Asian countries, and their meat is also widely consumed, especially in North America. Most rock sole are fished from the waters near Alaska. In 2008 alone, some 116 million pounds of rock sole were fished from the waters of the Bering Sea. While most rock sole can be found in the Bering Sea, the Puget Sound and the Gulf of Alaska, some southern species can be found as far south as the Pacific Ocean off the coast of Baja, Mexico.