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Giant sea bass

Bat Ray
Giant sea bass (Stereolepis gigas) in the Kelp Forest exhibit at the Monterey Bay Aquarium, a school of sardines swims in the background. This juvenile giant sea bass (Stereolepis gigas), estimated to be 4-5 months old, is 7.25 cm (3.5 in) long and weighs 10 grams (.35 oz).

On Exhibit: Monterey Bay Habitats

Animal Facts

  • Scientific Name

    Stereolepis gigas

  • Animal Type

    Fishes

  • Size

    maximum reported length 7.5 feet (2.3 m) and maximum reported weight 557 pounds (253 kg)

  • Range

    eastern Pacific Ocean from Humboldt Bay to southern Baja California, mostly south of Point Conception, California and in northern Gulf of California

Natural History

King of the kelp forest, the giant sea bass is California's largest nearshore bony fish. This top predator cruises slowly over rocky reefs and shallow sands—sucking up stingrays, squid, lobster, flatfishes, and even small sharks with a sudden gape of its immense mouth.

Evidence from ear bones (otoliths) indicates that giant sea bass live for at least half a century and may survive more than 70 years, barring a fateful encounter with a great white shark or a human angler. Much about this massive fish remains mysterious, complicating recovery efforts after the species teetered on the edge of extinction.

In summer months, giant sea bass gather to spawn in specific locations. A male may nudge a female to release up to 60 million eggs to be fertilized. Juveniles sport orange scales and black spots, but gradually turn gray and black in the dozen or so years it takes to reach reproductive age. After its first year of life, a juvenile is only 7 inches long—not yet a giant.


In Monterey Bay

Giant sea bass once ranged from Humboldt Bay in northern California to the southern tip of Baja California. Occasionally seen along the Central Coast, they rarely occur north of Point Conception and are more likely to be found around the Channel Islands or in the northern portion of the Gulf of California.


Conservation

A conspicuous target of commercial and recreational fishing, giant sea bass were often caught from fishing barges stationed along central and southern California in the 1920s and 1930s. Commercial catch for the species peaked in 1932 and began a dramatic decline in both California and Mexican waters. Before a law was passed to protect giant sea bass, the fishery shrunk by 95%.

In 1981, California's government banned intentional fishing for giant sea bass in coastal waters and restricted how many could be caught in Mexico and brought back to California. A 1994 ban on gill netting along the southern California coast reduced accidental capture of these megacarnivores. Since 1996, the International Union for Conservation of Nature (IUCN) has placed giant sea bass on its Red List as a critically endangered species.

Giant sea bass numbers may slowly be rising, but more data are needed to confirm an upward trend. The population of breeding females could total just a few hundred fish. Adding to the conservation challenges are the species' limited geographic range, depleted genetic diversity, and prolonged maturation. The recent statewide network of Marine Protected Areas (MPAs) should provide some refuge for the giant sea bass to rebound.


Cool Facts

  • The giant sea bass isn’t a sea bass at all. Its closest relatives are wreckfish.
  • Biologists at UC Santa Barbara have started a Great Giant Sea Bass Count each August, enlisting citizen naturalists and scuba divers to document sea bass numbers and location.
  • Kelpfish and other "cleaners" voluntarily pick parasites from the skin of giant sea bass.


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