The Secret Lives of SoCal Rockfishes

With more than 100 rockfish species worldwide, about 60 live in the ocean off the SoCal coast. Some are closely related and look very much alike. Colors of the same species can vary and at least some of the fish are chameleon-like, changing color to match their surroundings. Additionally, rockfishes are evolving and forming new species at what Dr. Milton Love calls “a frightening rate.” So is it any wonder many of them are a challenge to identify? I sought out Dr. Love’s expertise and his entertaining phonebook-sized tome, Certainly More Than You Want to Know About the Fishes of the Pacific Coast. Within its 650 pages is a treasure trove of information.

Rockfishes are members of the Scorpaenidae family and like the scorpionfishes, their head, anal and ventral fin spines are venomous. Unlike the scorpionfishes, rockfish spines are only slightly venomous and no danger to humans.
The rockfish genus name, Sebastes, means “magnificent” and the bodies of some but not all feature interesting patterns and bright colors. Brightly colored species command a higher price in the commercial market.
Rockfish fertilization is internal and occurs during a courtship “dance” initiated by the females. Some species may mate with more than one male. The eggs grow inside the mother and when they hatch, the larvae are expelled into the water, where they drift with the currents before morphing into juveniles that are not exact miniatures of their parents but share a resemblance.
When conditions are ideal, rockfishes can be very long lived. Age is ascertained by counting growth increments on the fishes’ otoliths, which is similar to counting the rings on a tree. The ear bones of one rockfish revealed it was more than 200 years old. The fish described here can live 25 to 30 years. The larger the species, the longer its life. The larger the female, the more young she produces. 
Some rockfish species stay close to home most if not all of their lives, others roam. A study of SoCal gopher rockfish, found on the California Fish and Game website (Status 2006 Gopher Rockfish), describes “three types of behavior: homebodies, commuters and floaters. The homebody types patrol and defend an area of the reef and occupy a shelter within it. The commuters are more transient, moving between shelter holes and feeding sites, but also displaying some territorial behavior. The floaters are non-territorial, inhabiting portions of other fish territories, and avoiding assault from dominant fish.”
Veteran divers have probably noticed there aren’t as many rockfishes around as there used to be. California rockfish populations have been declining for years. If MPAs work as hoped, perhaps they will rebound, though a significant population increase will likely take decades. The following are descriptions of four rockfishes commonly seen by California divers. 
Kelp Rockfish 
(Sebastes atrovirens)
For decades I have had company on my end-of-dive safety stops. When I grab onto a bunch of sturdy kelp stipes and look around, there is often at least one these fish nearby, usually hanging upside down, nearly motionless in the kelp, watching me. We used to call these fish “dumb bass.”
Although the species name, atrovirens, means “black and green” in Latin, the colors of kelp rockfish vary. Those I’ve seen hanging out in the kelp were often beige, with very faint markings. The one depicted here has more typical coloration, including freckle-like spots on its back and sides. It has changed its coloration to blend in with its surroundings. The large, filmy pectoral fins are a species characteristic.
Kelp rockfish are usually 6 to 14 inches long though they can reach a maximum of 17 inches. They are common from Central California to Baja, usually in 20 to 60 feet of water. Juveniles eat zooplankton, as do adults, though the latter also eat crustaceans and snails. Kelp rockfish are, in turn, eaten by other rockfishes.
Gopher Rockfish 
(Sebastes carnatus)
Gophers and the black and yellows are very closely related. Those two species are also close relatives of kelp rockfish. The species name, carnatus means “flesh-colored” in Latin. The fish’s colors range from olive-brown to reddish-brown with irregular patches of white or pink. These fish are highly territorial and most common in depths between 30 and 120 feet. 
Gopher rockfish range from Oregon to southern Baja. All of my gopher photos were shot off Big Sur, where I encountered solitary adults and small aggregations (two to three fish) of juveniles during a September multi-day trip in 2009. 
Gopher rockfish primarily feed at night on ground-dwelling crustaceans, fishes, gastropods and cephalopods. Adults of other species prey upon the juveniles.
Black and Yellow Rockfish 
(Sebastes chrysomelas
True to its species name, chrysomelas, which comes from two Greek words for “gold” and “black,” this fish is usually yellow and black, though sometimes the black is olive. Favorite foods include crabs and shrimp. The black and yellow rockfish is territorial and prefers depths shallower than 70 feet. Although it is uncommon south of Point Conception, my photo was shot at Santa Barbara Island. Because they are so closely related, much of what is written about gopher rockfish is also true of black and yellows. However, while most gophers live deeper than 40 feet, most black and yellows are found shallower than 60. Black and yellows range from Oregon to central Baja.
Treefish 
(Sebastes serriceps)
When encountered in its typical coloration, this is one the easiest SoCal rockfishes to identify. Its zebra-reminiscent stripes make it unique. The yellow body has five to six vertical bars (black, brown or dark green) and the lips are red, pink or orange. Of course, since it is a rockfish, there is a caveat: on occasion, Dr. Love says, the fish “are simply strewn with tiny light dots.” Newbie divers sometimes think the shy, pretty juveniles “bright yellow with black bars and markings, their oversized, fluttery fins trimmed in white or blue” are tropical fish gone astray. Treefish can be a maximum of 16 inches long and can live 25 years. They are common from SoCal to Baja in waters from 20 to 100 feet deep.
The treefish species name, serriceps, means “saw head” in Latin and when the head fin is raised, it does indeed resemble the teeth of a saw. Where the common name originated is unknown. These fish are most active in the evening. They eat crustaceans, octopuses, squid and other fish. They are often found in crevices and small caverns or partially hiding behind rocks. This is one rockfish that doesn’t stand its ground when approached by divers and in almost all of my photos it is leaving or about to leave the scene. It is only occasionally territorial. 
Rockfish Stats
Phylum: Chordata
Class: Actinopterygii
Order: Scorpaeniformes
Family: Scorpaenidae
Genus/species: 
Kelp rockfish (Sebastes atrovirens), Gopher rockfish (Sebastes carnatus)
Black and yellow rockfish (Sebastes chrysomelas), Treefish (Sebastes serriceps)
Maximum length (in inches): 
kelp 17, gopher 16, black and yellow 15, treefish 16
Lifespan: Kelp and gopher, 24; black and yellow, at least 30; treefish 25 years
Parturition (release of developed larvae): Kelp, February to August;
gopher, January to July; black and yellow, January to May; treefish March to July
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