Species Finder Species Posted Mar 17, 2000 Rockfish Other Names thornyheads, rock cod Species Identification There are dozens of species of rockfish in the world's oceans under the family name of Sebastidae. This section will look at the black rockfish and blue rockfish. *NOTE: "rockfish" is a common nickname for striped bass for anglers on the Atlantic Coast, but they are from a different family of fish. Appearance Black rockfish: The body of the black rockfish is oval or egg-shaped and compressed. The head has a steep upper profile which is almost straight; the mouth is large and the lower jaw projects slightly. The color is brown to black on the back, paler on the sides, and dirty white below. There are black spots on the dorsal fin. This species is easily confused with the blue rockfish; however, the anal fin of the black rockfish is rounded while the anal fin of the blue rockfish is slanted or straight. The black rockfish has spots on the dorsal fin, the blue rockfish does not. Blue rockfish: The body of the blue rockfish is oval or egg-shaped and compressed with similar dorsal and ventral profiles. The head is relatively short and bluntly pointed. The mouth is relatively small with the lower jaw slightly projecting. The color is dark blue or olive brown to grayish black on the back becoming lighter below; blotched with lighter shades on back and sides. The presence of five spines on the preopercle (gill cover), easily distinguish this species as a rockfish rather than a perch, a bass or a halfmoon which is of similar color. The black rockfish can be confused with this species; however, the black rockfish has spots on the dorsal fin while the blue rockfish does not. The anal fin of the black rockfish is rounded while that of the blue rockfish is slanted or straight. Maximum Size Black rockfish: Largest recorded length of 23.75 inches (60.3 cm). Can weigh over 13 pounds (6 kg). Blue rockfish: Largest recorded length of 21 inches (53.3 cm). Can weigh over 8 pounds (3.6 kg). Geographic Range Black rockfish: Black rockfish occur from Paradise Cove, California, to Amchitka Island, Alaska. They are wide-ranging fish that can live on the surface or on the bottom to 1,200 feet (365.7 m) near rocky reefs or in open water over deep banks or drop-offs. Blue rockfish: The blue rockfish occurs from Punta Baja, Baja California, to the Bering Sea. It is a schooling species that is often caught in large numbers over rocky bottoms and around kelp beds. It is most commonly caught from the surface to 100 feet (30.5 m), although it has been taken from depths as great as 300 feet (91.4 m). Habitat Rockfish prefer rocky environments, with depth ranging from species to species. Food Black rockfish: squid, crab eggs, and fishes. Blue rockfish: small fishes, shrimps, other crustaceans and small pieces of algae or seaweed. Reproduction Black rockfish: Black rockfish are ovoviviparous, like all members of this family fertilization and development of the embryo take place in the body of the mother. When embryonic development is complete, the female releases the eggs and the exposure to sea water activates the embryo and it escapes from the egg case. Blue rockfish: As with other rockfishes, fertilization is internal and live young are born which are quite small and helpless. A 16-inch (40.6 cm) female contained just over 500,000 eggs. The main spawning season runs from about November to March. Information courtesy of California Department of Fish and Game.