Chrysomelas, which is Latin for black and yellow, describes the coloration of this species. They are black or dark brown with yellow blotches. Gopher rockfish (Sebastes carnatus) resemble them very closely, but gophers are brown or dark brown with large pink or whitish blotches. Both species are deep bodied with large head spines.
Distribution, Stock Structure and Migration
Black-and-yellow rockfish are distributed from Cape Blanco, Oregon to Isla San Natividad, central Baja California, but they are less common south of San Diego, California. They are demersal (bottom dwelling), usually in water less than 60 ft, although they have also been found at depths up to 120 ft. They are a residential species that inhabit kelp beds and rocky reefs. After establishing residence, the adults are highly territorial and travel no more than 2 km from their home range.
Age and Growth
Whole otoliths have been used to age this species to a maximum of 30 yr. Based on a calculated age-length relationship, an 8-in. TL black-and-yellow rockfish is approximately 3-4 yr old, and a 10-in. fish is approximately 6 yr old, and a 12-in. fish is 10-11 yr old. The maximum-recorded total length of this species is 15.3 inches.
Reproduction, Fecundity and Seasonality
In central and northern California waters, males and females reach first maturity at 3 yr old, possibly as old as 4 yr for males and 6 yr for females. Corresponding total lengths range from 5.1 to 9.4 in. TL for males, and 5.3 to 9.6 in. TL for females. Fifty percent of the male population will reach maturity at 3 yr old, between 5.1 and 6.5 in. TL, while half of the female population will reach first maturity between 5.3 and 6.3 in. TL, at 3 or 4 yr old.
Spawning occurs off California from February through the end of July, with peak spawning in February and March. Female black-and-yellows may be carrying fertilized eggs anytime between October and the end of February. In central California, June is the primary month of first appearance of young-of-the-year in kelp bed areas, and they are usually first observed in the kelp canopy.
Estimates of natural mortality are not available for black-and-yellow rockfish.
Adult black-and-yellows are nocturnal feeders, ambushing their prey between dawn and dusk. Predators of the adults include sharks, dolphins, and seals, while juveniles are prey of birds, porpoises, and fishes, including rockfishes, lingcod, cabezon, and salmon.
Black-and-yellow rockfish probably compete for food and space with gopher rockfish. When both species are present, the more aggressive black-and-yellows exclude gophers from shallower depths.
Larvae and young juveniles are pelagic, but the juveniles will eventually become demersal and settle on nearshore rocky areas or in kelp forests. Among the nearshore rockfishes, this species and grass rockfish have the most shallow depth distributions.
Status of Stocks
No formal stock assessments have been made for this species.
Information on this page was originally presented in the Nearshore Fishery Management Plan (these profiles updated July, 2010).