This issue's centerfold is the copper rockfish. The scientific name of the copper rockfish is Sebastes caurinus. Sebastes means "magnificent" and caurinus means "northwest", referring to the geographic area where the species was first described. Common nicknames for copper rockfish are chucklehead and whitebelly rockfish. Whitebelly rockfish were formerly classified as a separate species, but are now recognized as copper rockfish.
Copper rockfish can be distinguished from the other rockfishes by the clear area along the posterior two-thirds of the lateral line, the whitish belly, and a body color that is not basically reddish or orange (though patches of reddish color may be present). Patches of yellow or copper color are often present near the gill covers.
Copper rockfish are distributed along the Pacific coast from Baja California to the Kenai Penninsula, Alaska. They have been taken in waters ranging in depth from a few feet to as deep as 600 feet.
The squat body shape and rounded caudal (tail) fin attest to the lifestyle of copper rockfish: they are unschooled, antisocial low-lifes. That is, they generally are found on the bottom, and adults are highly residential, usually remaining near their home site on a rocky reef. Adults are found as solitary individuals, not in schools.
Like all rockfishes, copper rockfish reproduce by internal fertilization, but relatively little development occurs within the female. A single female will extrude about 100,000 to 300,000 larvae into the water column. Release of larvae occurs in February in California waters. The larvae drift in offshore waters where they develop into juveniles until May, when they move inshore. Copper rockfish generally mature sexually at 4 to 6 years of age. A 13 inch fish is about 4 to 6 years old, and a 16 inch fish is about 7 to 8 years old. The maximum known age is 35 years. Adults feed mainly on crabs and fish.
Copper rockfish are not as common along the Mendocino-Sonoma coast as other rockfishes such as blue rockfish, black rockfish, and yellowtail rockfish. Historical sport fishing survey data from Arena Cove, Mendocino County, suggest that the relative abundance of copper rockfish may once have been greater than it is today; average catch per day of copper rockfish was 1.9 fish in 1959, 1.2 fish in 1972, and 0.1 fish in 1980-86. Demersal (bottom-dwelling) rockfish species such as copper rockfish do not seem to hold up under fishing pressure as well as species found higher in the water column such as blue rockfish and yellowtail rockfish. In 1993, copper rockfish comprised about 2% by number of the sport fish catch from boats along the Mendocino-Sonoma coast.
Like many rockfishes, the average size of copper rockfish taken by sport fisheries has become smaller since the early 1980s. In northern and central Californi, average weight of fish taken by party boats (also known as commercial passenger fishing vessels or CPFV's), decreased from about 1.5 kg to 1.1 kg (Figure 7). Average weight from skiffs decreased from 1.1 kg to 0.7 kg (1 kg equals 2.2 lb). The trend is difficult to interpret with certainty. Mean weight of rockfishes can fluctuate due to natural population boom-and-bust cycles. The most probable explanation, however, is that ongoing sport and commercial fishing pressure is causing the portion of larger, older fish in the population to decrease, a phenomenon observed in other rockfish species. The trend is cause to keep a watchful eye on the status of the stocks. - DA
