Giant Sea Bass (Adult)
Stereolepis gigas

 

Physical Description

  • Adult giant sea bass have bulky bodies and large mouths, with tiny teeth.
  • Dark brown to grayish-black coloration with lighter stomachs, dark spots all over.
  • Dorsal (back) spines fit into a groove in their back.
  • Capable of weighing over 700 pounds and being over 7 feet long.
  • Adults look very different than juveniles (#72).

Range

  • From Humboldt Bay, California to Cabo San Lucas, Baja California, Mexico.
  • Throughout the Gulf of California.
  • Sporadic/rare north of Point Conception.

Habitat

  • Live in kelp forests and sandy environments.

Reproduction

  • Males reach sexual maturity at 40 pounds, females at 50-60 pounds (age 11-13 for both genders).
  • Spawn from July-September, where one female may produce 60 million eggs!
  • Eggs are 1/24th inch in diameter and float to the surface.
  • Larvae drift and feed on plankton for about a month before becoming juveniles.

Diet

  • Generalist predators (meaning they will eat almost anything).
  • Fishes, crustaceans, small sharks, small rays, squid, razor clams, and other invertebrates.
  • Eat by abruptly opening their jaw, creating a strong vacuum, and sucking in their prey.

Predators

  • The only known natural predators of giant sea bass are great white sharks.

Interesting Facts

  • They are the largest resident bony fishes in California.
  • They are long-lived, capable of living 72-75 years, and do not reproduce for the first time until 13-15 years of age.
  • The largest giant sea bass ever recorded was 7.4 feet long and weighed 563.5 pounds! 
  • One ovary of a GSB can weigh 47 pounds and contain 60 million eggs!
  • They can temporarily flash, or change, the brightness of the color of their skin or spots.
  • Giant sea bass produce booming sounds that are thought to be associated with aggressive and/or courtship behavior.
  • Giant sea bass form spawning aggregations, or gatherings. A historical aggregation was documented off of Point La Jolla, but disappeared likely due to the overfishing of the species. One of the goals of current Scripps research is to see if they can identify a current spawning aggregation site in La Jolla by tagging and tracking giant sea bass individuals in the La Jolla Kelp Forest.

Sources: spottinggiantseabass.msi.ucsb.edu; California Department of Fish and Wildlife; Kayla Blincow, Scripps Institution of Oceanography; National Park Service

Photo: Tracy Clark

In Birch Aquarium’s kelp tank, there is a Giant Sea Bass that is approximately 300 pounds and 25 years old! Dedicated to Walter Munk himself, this fish is truly impressive. See if you can spot her on Birch Aquarium’s Kelp Cam!