Abbreviated Life History of Copper Rockfish
(Sebastes caurinus)

China Rockfish; Photo by Steve Lonhart of Simon/NOAA

The copper rockfish is a highly variable species in terms of coloration, and due to this characteristic has been known by several names, depending to some degree upon locality. At one time, copper were thought to be three distinct species. A light-colored stripe along the rear two-thirds of the lateral line is a constant character. They are deep-bodied and have prominent spines. Common colors include olive or dark brown, and coppery-pink, although the red variation is common off California.

Distribution, Stock Structure and Migration

The copper rockfish is broadly distributed geographically, known from the northern Gulf of Alaska to off central Baja California. It also has a broad bathymetric distribution, occurring from the shallow subtidal to 620 feet, but are most common around 90 feet.

Tagging studies indicate that copper rockfish, for the most part, show little movement once they have settled to the bottom. Movement of up to one mile has been noted, but the majority of tagged and recaptured copper rockfish are from the locality where they were originally taken. High site fidelity makes this species susceptible to local depletion.

Adults are associated with boulder fields and high-relief rocks, and they are found in small aggregations or as solitary individuals. However, off some oil platforms in southern California, copper rockfish have been observed in aggregations of 50–100 individuals.

Age and Growth

Copper rockfish have been aged to 50 years. One study off Monterey, California, shows females grow larger than males. The maximum recorded length for copper rockfish is 26.4 inches.

Reproduction, Fecundity and Seasonality

Off central and northern California, males and females mature at the same length. Fifty percent mature at 12.5 inches or four years. All are mature at 15.6 inches or seven years.

As will all rockfishes, coppers are viviparous and highly fecund. Female coppers release between 16,000 and 640,000 eggs per season. Mating occurs in the fall, and in California, larvae are released in a single batch during winter months (January thru April) with a peak in February. Larval duration is one to two months. Copper rockfish lack an extensive pelagic juvenile stage. Young-of-the-year copper rockfish recruit into the nearshore environment at about 1.8 to 2.0 inches during April and May off central California. Juveniles descend to the bottom over sand or low rock within a few months.

Natural Mortality

Calculations of natural mortality have been made from populations in Puget Sound, Washington, and was calculated to be 0.1127 using tag/recapture method on fish 5 to 34 year old.

Predator/Prey Relationships

Copper rockfish feed on a wide variety of prey items. Juvenile copper rockfish feed primarily on planktonic crustaceans like copepods. Larger crustaceans form a major part of their diet as they grow; these include Cancer sp. crabs, kelp crabs, and shrimps. Squid of the genus Loligo and octopi are also important food items. Adult coppers usually feed close to the bottom. Fishes, including young-of-the-year rockfishes, cusk-eels, eelpouts, and sculpins, are important prey for larger individuals. As juveniles and adults, copper rockfish are preyed upon by a variety of fishes including other rockfishes, lingcod, cabezon and salmon as well as several species of birds and mammals.

Competition

Due to their co-occurrence with other larger benthic fish species such as cabezon, lingcod, greenlings, and rockfishes such as vermilion, brown, and China, it is likely that some degree of competition for food and space may occur.

Critical Habitat

Newly recruited copper rockfish initially associate with surface-forming kelps. After several months, and at about 2.0 inches, the juveniles settle to the bottom on rocky reefs as well as sandy areas and are referred to as benthic juveniles. Adults are commonly found in kelp bed areas but also frequent deeper rocky reefs. As adults, this species is considered to be epibenthic, normally occurring slightly above the substrate, which is often high-relief rocky shelf and rock-sand interface.

Copper rockfish are an important component of the nearshore rocky reef system and are frequently encountered by scuba divers in this environment. Submersible observations of the biotic community off the Big Sur coast, Monterey County, revealed copper rockfish between depths of 72 to 322 feet. The majority of sightings were of individual (solitary) fish occurring over rocky reef or boulder fields and most frequently in areas of high relief. Occasionally an individual was observed over sand.

Fishery and Status of Stocks

Copper rockfish is important for the commercial live-fish fishery, mainly because of their abundance and hardiness. Copper rockfish are an important component of the recreational catch in both skiff and commercial passenger fishing vessel fisheries, especially off central and northern California. Due to its relatively large size, copper rockfish are considered one of the premium species in the recreational catch and a prime target for the sport diver. Their solitary nature, high habitat specificity, and size they can enter the fishery (as juveniles), make the copper rockfish a candidate for local depletion.

There has been no formal stock assessment of this species in California. However, there is compelling evidence that copper rockfish populations have severely declined in many areas, and large individuals are noticeably less common than in past decades. There is considerable evidence that the copper rockfish population in Puget Sound has been overfished. Copper rockfish are managed as a component of the Nearshore Rockfish category.

Information on this page was originally presented in the Nearshore Fishery Management Plan (these profiles updated July, 2010).

Copper Rockfish