Giant sea bass was originally assigned to the grouper family, Serranidae, but was later placed in a new family called the Percichthyidae (Domeier 2001).

Giant Sea Bass was classified as a Critically Endangered species by IUCN in 1996. This assessment presents additional information to support that assessment. The American Fisheries Society classified the species as Threatened (Musick et al. 2000).

Pre-exploitation biomass for Southern California populations of the Giant Sea Bass was estimated to be 1,300 tons (1,179 tonnes) (Ragen 1991). The fish was so heavily exploited in both California and Mexican waters that the commercial landings declined rapidly from 115 tonnes in 1932 to 5 tonnes in 1980 in California waters, whereas it decreased greatly from 363 tonnes to 12 tonnes in Mexican waters over the same period (Domeier 2001). The annual landings (in tonnes) of the species in California fluctuated in the 1990s: 3.3 (1990), 5.3 (1991), 3.9 (1992), 2.1 (1993), 0.4 (1994), 0.5 (1995), 0.9 (1996), 1.1 (1997), 2.9 (1998), 2.4 (1999), 2.0 (2000) and 2.6 (2001) (NMFS 2003). Reports of landings from Hawaii from NMFS, WpacFIN website and DAR (2003) are in error, the correct species being Epinephelus quernus. The error is due to the wrong common name being used in these reports (W. Ikehara pers. comm.).

Currently, it is suggested that the population size of Giant Sea Bass in California may be increasing as it is under protection (Domeier 2001); however, there are no hard data to support it. Due to the heavy harvest in Mexico and the long generation time (estimated at 7–10 years) (Domeier 2001). It is also possible that the species may need additional protection in Mexico but more information is needed. The current status should not be changed until data about the actual or relative abundance of the species are collected.

The species is particularly vulnerable due to its very limited distribution, its very large size and its aggregation spawning. It is not known how effective management is.

Eastern Pacific: from Humboldt Bay in California, U.S.A. to the tip of Baja, Mexico; also found in the northern half of the Gulf of California (Domeier 2001). Supposedly also occurs in the coastal waters of northern Japan (the Sea of Japan) (Masuda et al. 1992); but the occurrence in Japan is probably a misidentification (Domeier 2001).

It is now very rare in the Gulf of California (Musick et al. 2000). Minimum population doubling time is more than 14 years (Musick et al. 2000).

Juveniles are usually found in and around kelp beds as well as sandy bottom areas at depths 12–21 m (Crooke 1992), whereas adults are usually found deeper than 30 m and they tend to inhabit rocky bottoms where kelp beds are nearby (Eschmeyer et al. 1983).

Reproductive Biology
The fish mature at 7 to 10 years (Domeier 2001). The maximum size of male/unsexed giant sea bass is 250 cm TL (IGFA 2001). Spawning aggregations are formed and remain together for one or two months over the period of June to September (Crooke 1992).

The major threat is from overfishing; however, the species is protected in California (this legislation also covers U.S. fishers in Mexican waters) although incidental catches are allowed (see Conservation Measures below).

The fish has been protected in California since 1982 and protected in Mexico since 1992 (Crooke 1992).

California State Legislature banned both commercial and recreational fishing for Giant Sea Bass in 1981 in response to the great decline in population, but it allowed two fish per angler per trip when fishing south of United States-Mexico border (Crooke 1992) and allowed one fish per trip if taken incidentally in gill or trammel net by commercial fisherman (Domeier 2001).

The species can still be caught in Mexico (M. Domeier, pers. comm.).

The law limited the amount of Giant Sea Bass that could be taken in Mexican waters and landed in California (could not land more than 3,000 lbs in a calendar year). The ban of inshore gill nets in California was introduced in 1990, which was considered a way to significantly reduce the incidental mortality of Giant Sea Bass (Domeier 2001).