Grass Rockfish

Grass Rockfish, Sebastes rastrelliger

Grass Rockfish, Sebastes rastrelliger, Juvenile. Fish caught off the beach at Santa Cruz, California, November 2020. Length: 8.2 cm (3.2 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Grass Rockfish, Sebastes rastrelliger, Juvenile. Fish caught from coastal waters off Half Moon Bay, California, September 2023. Length: 12 cm (4.7 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Grass Rockfish, Sebastes rastrelliger. Fish caught off the beach at Santa Cruz, California, November 2020. Length: 30 cm (12 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Grass Rockfish, Sebastes rastrelliger. Fish caught from shore in Big Sur, California, January 2011. Length: 30 cm (12 inches). Catch and photograph courtesy of Eli (obsessiveangling.wordpress.com). Identification courtesy of Milton Love, University of California, Santa Barbara, Goleta, California.

Grass Rockfish (1)

 Grass Rockfish, Sebastes rastrelliger. Fish provided by the commercial fishermen of the greater San Diego area, San Diego, California, October 2014. Length: 38 cm (15 inches).

The Grass Rockfish, Sebastes rastrelliger, is a member of the Rockfish and Scorpionfish or Scorpaenidae Family, and is known in Mexico as rocote de olivo. 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 Grass Rockfish has a heavy-body, stubby, and spiny fish with a body depth that is 30% to 34% of standard length. They have an olive green coloration with intermittent and irregular dark brown blotches which are lighter ventrally. Their fins are similar in color to the darker portions of the body. Their heads are wide with a tapering snout. Their anal fin has 3 spines, the second being stout and mid-length, and 6 rays; their caudal fin is broad, fan-like, and rounded with a wide peduncle; their dorsal fin has 13 spines and 12 to 14 rays;  and, their pectoral fins have 18 to 20 rays. They have 17 to 25 short stubby gill rakers on their first arch. Their body is covered with scales.

The Grass Rockfish reside within heavy rocky structures at depths up to 55 m (180 feet); they are one of the very few shallow water Rockfish. They reach a maximum of 56 cm (22 inches) in length, with males and females being of similar length. As of January 1, 2023, the International Game Fish Association world record stood at 2.89 kg (6 lbs 6 oz) with the fish caught in coastal waters off Newport, Oregon in March 2007. They feed on bottom dwelling crustaceans and small fish. They have lifespans of 23 years. The Grass Rockfish 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 Grass Rockfish is a resident of Mexican waters of the Pacific but has a limited range being found from Cedros Island, Baja California, northward along the central and northwest coasts of Baja.

The Grass Rockfish can be easily confused with the Brown Rockfish, Sebastes auriculatus (21 – 30 long gill rakers; dark blotch on gill cover).

From a conservation perspective the Grass Rockfish has not been formally evaluated. They are a strong component of the California commercial fishery with most fish taken via gill nets and hook and line; the fish is retained live and sold to ethnic markets. They are also caught close to shore by recreational anglers and divers. They are considered an excellent food fish.