Halfbanded Rockfish

Halfbanded Rockfish, Sebastes semicinctus

Halfbanded Rockfish, Sebastes semicinctus. Fish caught from coastal waters off Dana Point, California, December 2022. Length: 12 cm (4.7 inches). Catch, photograph, and identifications courtesy of Chris Moore, Peoria, Arizona.

Halfbanded Rockfish, Sebastes semicinctus. Fish caught from coastal waters off San Diego, California, October 2014. Length: 18 cm (7.1 inches).  Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

Halfbanded Rockfish (1)

Halfbanded Rockfish, Sebastes semicinctus. Fish provided by the commercial fishermen of the greater San Diego area, San Diego, California, October 2014. Length: 18 cm (7.1 inches). Identification courtesy of Milton Love, University of California, Santa Barbara, Goleta, California.

Halfbanded Rockfish (3)

Halfbanded Rockfish, Sebastes semicinctus. Both fish caught from coastal waters off Long Beach, California, July 2015. Length of each: 12.7 cm (5.0 inches). Photographs courtesy of Chris Wheaton, Fullerton, California.

Halfbanded Rockfish, Sebastes semicinctus. Fish caught from coastal waters off Tijuana, Baja California, February, 2023.. Length: 14 cm (5.5 inches). Catch, identification and photograph courtesy of Luke Ovgard, Klamath Falls, Oregon.

Halfbanded Rockfish, Sebastes semicinctus. Fish caught from coastal waters off Tijuana, Baja California, February 2022. Length: 15 cm (5.9 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Halfbanded Rockfish, Sebastes semicinctus. Fish caught from coastal waters off San Diego, California, December 2020. Length: 16.6 cm (6.5 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

The Halfbanded Rockfish, Sebastes semicinctus, is a member of the Rockfish and Scorpionfish or Scorpaenidae Family, and is known in Mexico as rocote inspector. 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 Halfbanded Rockfish has a slender body with a depth that is 28% to 32% of standard length. They vary in color from orange to deep red or brown and transition quickly to white ventrally. They have a diamond-shaped dark mark that runs from under their spiny dorsal fin to below their lateral line. They also have 2 additional bands toward the rear of their body. Their body is heavily blotched and saddled. Their caudal fin has brown and green streaks and is covered with dots. They have the ability to change colors and patterns. They have a long head with a short snout, disproportionately large eyes, and a relatively small terminal mouth. Their anal fin has 3 spines and 6 to 8 rays; their caudal fin is slightly forked; their dorsal fin has 13 spines and 12 to 14 rays; and, their pectoral fins have 16 to 18 rays. They have 36 to 42 gill rakers and their body is covered with scales.

The Halfbanded Rockfish is a demersal species that is found within a wide variety of habitats ranging from muddy floors to hard rockscapes at depths between 15 m (50 feet) and 402 m (1,320 feet). They are found as individuals or in schools that number in the thousands and are one of the most abundant species in mid-depth reefs. They reach a maximum of 25 cm (10 inches) in length, with females being larger than males. They feed on zooplankton including amphipods, copepods, crustacean larva, and krill. Reproduction is oviparous with each female releasing between 3,000 and 31,000 pelagic eggs. They have a lifespan of up to 15 years. The Halfbanded 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 Halfbanded Rockfish is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Guerrero Negro, Baja California, northward along the central and northwest coasts of Baja.

The Halfbanded Rockfish is easily confused with the Stripetail Rockfish, Sebastes saxicola (lacks dark mid-body diamond-shaped bar).

From a conservation perspective the Halfbanded Rockfish has not been formally evaluated. Being small in stature they are not fished commercially. They are caught with some regularity by recreational fishermen but in limited quantities due to their small mouths.