Blue Rockfish, Sebastes mystinus

Blue Rockfish, Sebastes mystinus, Juvenile. Fish caught from coastal waters off Santa Cruz, September 2023. Length: 7.9 cm (3.1 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Blue Rockfish, Sebastes mystinus, Juvenile. Fish caught from coastal waters off Brookings, Oregon, December 2020. Length: 8.5 cm (3.3 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Blue Rockfish, Sebastes mystinus, Juvenile. Fish caught off the Coast Guard Pier, Monterey, California, June 2022. Length: 11.7 cm (4.6 inches). Catch, photograph and identification courtesy of George Brinkman, Guelph, Ontario, Canada.

Blue Rockfish, Sebastes mystinus. Fish caught from coastal waters off Santa Cruz, September 2023. Length: 12.3 cm (5.0 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Blue Rockfish, Sebastes mystinus, Blue-blotched Morphology. Fish caught from coastal waters off San Diego, California, October 2018. Length: 22 cm (8.7 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Blue Rockfish, Sebastes mystinus, Blue-blotched Morphology. Fish caught from coastal waters off the Channel Islands, California, August 2019. Length: 32 cm (12.5 inches). Catch, photograph and identification courtesy of George Brinkman, Guelph, Ontario, Canada.

Blue Rockfish, Sebastes mystinus, Blue-blotched Morphology. Fish caught from coastal waters of Long Beach, California, October 2015. Catch, photograph and identification courtesy of Chris Wheaton, Fullerton, California. Identification reconfirmed by Milton Love, University of California Santa Barbara, Goleta, California.

Blue Rockfish, Sebastes mystinus, Blue-blotched Morphology. Underwater photograph taken in the coastal waters off Monterey, California, February 2022. Photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Blue Rockfish, Sebastes mystinus, Blue-blotched Morphology. Photograph of a living resident of the Birch Aquarium, La Jolla, California, January 2008.

The Blue Rockfish, Sebastes mystinus, is a member of the Rockfish and Scorpionfish or Scorpaenidae Family, and is known in Mexico as rocote azul. There are two genetic morphologies of this species, the “Blue-blotched” and the “Blue-sided”. Globally, there are one hundred eight species in the genus Sebastes, of which fifty-three are found in Mexican waters, all in the Pacific Ocean.

The Blue Rockfish has an elongated oval body with a depth that is 32% to  36% of standard length. The Blue-blotched Rockfish have a blue coloration with light gray or white blotches. They have 2 colored cheek bars and bluish stripes across their heads. The Blue-sided Rockfish have an olive brown coloration with more uniform blotching. Their head is mid-sized with a mid-length snout, mid-sized eyes, a relatively small terminal mouth, and a limited number of spines. The Blue-sided Rockfish has a more pointed snout, a more prominent lateral line, and is more elongated that the Blue-blotched Rockfish. Their anal fin has 3 spines and 8 to 10 rays; their caudal fin is rounded; their dorsal fin has 13 spines and 15 to 17 rays; and, their pectoral fins have 16 to 18 rays. They have 32 to 39 gill rakers and their body is covered with scales.

The Blue Rockfish is a non-migratory schooling reef fish that is found in all parts of the water column at depths up to 550 m (1,800 feet). They reach a maximum of 53 cm (21 inches) in length, with females being larger than males. As of January 1, 2024, the International Game Fish Association world record for length stood at 59 cm (23 inches) with the fish caught from coastal waters off Pry Island, Alaska in August 2013. The corresponding world record for weight stood at 3.79 kg (8 lbs 6 oz) with the fish caught in coastal waters off Alaska in July 1994. They are normally mixed in with Blacksmiths and Olive Rockfish. They feed primarily on planktonic organisms. Reproduction is oviparous with each female releasing up to 525,000 pelagic eggs. They have lifespans of up to forty-four years. The Blue Rockfish, including the two morphologies of this species, is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Blue Rockfish is a resident of Mexican waters of the Pacific Ocean but has a very limited range being found from Puerto Santo Tomas, Baja California, northward along the extreme northwest coast of Baja.

The Blue Rockfish is most likely confused with the Black Rockfish, Sebastes melanops (strong mottled pattern; large mouth).

From a conservation perspective the Blue Rockfish has not been formally evaluated. They are an important commercial catch in California waters. They are primarily sold live, however, they do not command high prices due to their drab coloration. They are also a major focus of recreational anglers being the most abundant catch of party boat anglers in Central California. They are also taken by spear fishermen is substantial quantity. Due to these pressures the abundance of the Blue Rockfish has significantly diminished in recent years.