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Target Species Profiles

Giant (black) Sea Bass (Stereolepis gigas)

Giant Sea Bass

Written by: Dr. Larry Allen

(originally printed in Western Outdoors News 1993)

Last year while trawling in Newport Bay on a sampling trip for Cal Fish and Game's BENES program targeting local sport fishes, something memorable happened. I was in the wheel house of our research vessel, the R/V Yellowfin (I am often there during trawls since I have become somewhat jaded after seeing thousands of them over the last 20 years.). I typically give my research assistants the responsibility of the sorting and work-up of the catch.  They thrive on the experience, just as I did 20 years ago. Usually toward the end of the work-up, I wander down to the back deck to check on the progress and to look at any rare or otherwise neat critters that may have come up. This particular trawl just north of Lido Island in Newport Harbor was unique. Almost as soon as the trawl had hit the deck, my chief research assistant, Motz (Tom Grothues), began yelling something about a black sea bass. I was on the back deck in an instant grumbling in disbelief. I had never seen or heard of a black (or now, more properly, a giant) sea bass being taken from inside Newport Bay in all of my 20 years of experience there. But, sure enough, there it was. An absolutely gorgeous little fish about 6 inches long. It was reddish-bronze in color with jet-black circular spots and huge black fins. This little fish was easily one of the neatest things I have ever seen. We fussed over it, took pictures in our live tank, deflated its swimbladder, and released it. Such chance encounters present the rare opportunity to glimpse a mystery much greater than our individual selves, something truly cosmic. From the likes of this tiny, elegant fish -- the largest, the eldest, and most magnificent of our nearshore fish species will emerge. Sadly, this awesome creature was over-fished to the virtual brink of extinction within my lifetime.

            The scientific name of the giant sea bass (black sea bass) is Stereolepis gigas which is Greek for the "firm-scaled giant". Very little at all is known about the life history of giant sea bass. This seems surprising to me since they have been the subject of commercial fishing since about 1870 with a sport fishery existing since 1895. Part of the reason for this lack of information must have been the general practice of dressing-out (beheading and gutting) the fish shortly after capture by commercial fisherman. (I learned this and many other pertinent facts from the excellent summary on the current status of the giant sea bass by DFG's Steve Crooke in the 1992 release of "California's Living Resources and Their Utilization".) The head and gut of a fish contain the structures most useful to the study of life history. Another likely reason is that the giant sea bass has never been the sole subject of a directed study. What little biological information we do have about this important fish was collected mainly by the late, great, fish and game biologist, John E. Fitch.

            Giant sea bass occurs from Humboldt Bay in northern California, south to the tip of Baja California, but it rarely occurs north of Pt. Conception. An apparently disjunct population also occurs in the northern half of the Gulf of California. Adults prefer rocky bottom habitat located near kelp beds and are most common at depths of between 110 and 150 feet. Juveniles tend to occur in shallower water (40 to 70 feet) around kelp beds, but have been also been found over sand bottoms in association with drift algae.

            The giant sea bass is the largest and oldest of our nearshore "sport" species reaching 7.5 feet and 539 pounds. (They are, technically, no longer sport species in California waters since it is now illegal to catch and keep them.) The oldest known giant seabass was a 435 pound fish aged at between 72 and 75 years. The record 539 pounder was reported to be "only" 60 years old. It seems to be a common belief among biologists who have written about giant sea bass that they may reach 90 to 100 years of age -- this is conjecture since none of the available data supports this conclusion.

            Giant sea bass grow to sexual maturity in 11 to 13 years when they are about 50 to 60 pounds. Spawning takes place from June to September. In the past, this spawning period was the time that giant sea bass were most vulnerable to exploitation since numbers of large fish form spawning aggregations that may remain together for one or two months. Although almost nothing is known about the reproductive biology of the giant sea bass, at least we know that females are capable of producing extremely large numbers of eggs. In August 1958, one female giant sea bass weighing 320 pounds was captured. Its ovaries weighed a total of 47 pounds and contained approximately 60 million eggs.

            Adult giant sea bass eat pretty much anything they want including fairly large spiny lobsters which they are more than capable of sucking out of their crevices with their large, gaping mouths. Giant sea bass have been classified as the only "megacarnivore" inhabiting the kelp beds in southern California. Among the other larger food items found in the stomachs of large fish are Pacific mackerel, ocean whitefish, midshipmen, stingrays, white croakers, small sharks, crabs, and mantis shrimp. Adults have even been known to run down and consume bonito over short distances! Juvenile fish tend to eat a more familiar diet of anchovies, sardines, and squid.

            Two extremely significant fishery management decisions regarding giant sea bass were enacted in 1982. First, the California State Legislature, in response to greatly depressed population levels, banned the commercial fishing of giant sea bass in California waters. Since this same legislation also permits the taking of one giant sea bass per trip for commercial gill nets, a very low-level fishery does still exist. Secondly, the California Fish and Game Commission banned sport landings from California while allowing anglers two fish per trip from Mexican waters on long-range expeditions. 

            Commercial fishing of giant sea bass began in California waters, but quickly moved south as the local population numbers declined. Initially, fish were taken using handlines, but later gill nets were employed as the resource continued to decline. Landings ranged from a high of about 860,000 pounds (dressed-out) in 1934 to a low of 3,600 pounds in 1983, the year after the moratorium. During the 1970s, catches ranged from 129,000 to about 38,000 pounds showing a steady decline through 1981. After the moratorium in 1982, catches decreased substantially. For the period of 1983 to 1992 these incidental catches have remained low ranging from 13,000 to 3,700 pounds.

            The sport fishery for giant sea bass has, historically, accounted for a much lower catch than commercial and has fluctuated normally between about 50 to 600 fish per year during the period of 1947 to 1981. The highest sport catch was recorded in 1973 (816 fish), and a low of 13 fish was reported in 1983, the first full year of the moratorium. According to Commercial Passenger Fishing Vessel (CPFV) logs, the majority of the sport-caught fish have been less than 80 pounds, although some fish over 500 pounds were taken, as well.

            Since the 1982 ban on recreational fishing, an ever increasing number of juvenile giant sea bass are being reported as caught and released. I know it always does may heart good to see those mentioned in the L.A. Times Fish Report each morning. If properly handled with no rough-stuff (e.g., gaffing, bouncing on the deck, etc.) and proper deflation of the swimbladder, a giant sea bass probably stands an excellent chance of survival. So, there is hope! There seem to be more juvenile giant sea bass around now than in the recent past. They are, hopefully, making a come-back. Make no mistake though, this is very slow-growing, late-maturing, long-lived species. Giant sea bass will take many years to recover from our collective heavy-handedness.

 

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