Black sea bass  (Stereolepis gigas)

The black sea bass has been massively over-fished in both California and Mexican waters, leaving this water giant Critically Endangered. Indeed, so dramatic were these declines that between 1932 and 1980 commercial landings diminished from 115 tonnes biomass to 5 tonnes in Californian waters, and from 363 tonnes to 12 tonnes in Mexican waters. The species’ limited distribution, large size and aggregation in spawning areas made it an easy target for fisheries (1). Unfortunately, its slow growth and late onset of sexual maturity make the fish extremely vulnerable to population collapses from over-fishing, and slow to recover (5). Additionally, it appears that the black sea bass may also be suffering from toxin poisoning. Sediments along the coast of California have been found to carry very high levels of toxins such as DDE and PCB, with an area off the Palos Verdes peninsula thought to contain possibly the highest loads of DDE (a breakdown product of DDT) in the world’s oceans. The toxins cannot be broken down so, as a mid-level predator, black sea bass ingest the cumulative toxins in increased concentrations from the food chain below it, and have been found to be carrying extremely high body burdens of DDE and PCB in southern California. The chemicals have been recorded to interfere with normal reproductive biology in other species of fish, as well as amphibians, reptiles and birds, but more research is needed into the effects they are having on this giant fish and its process of recovery in California (3).

The black sea bass has been protected in California since 1981 and in Mexico since 1992. Both commercial and recreational fishing of this species were prohibited in California in 1981, although two fish per angler per trip are allowed to be caught south of the U.S.-Mexican border and one fish per trip to be taken incidentally by commercial fishermen. The law also limited the amount of black sea bass that could be caught in Mexican waters and landed in California (1). Although these laws have prevented commercial fishermen from targeting and profiting from these fish, they have failed to protect the habitats occupied by the species from fishing and have probably done little to reduce incidental mortality, since black sea bass entangled in nets have simply been discarded back into the sea (5). Indeed, many fish in spawning aggregations in the summer have been caught and released, frequently receiving injuries in the process (6). However, the banning of gill nets in California in 1990 has probably helped significantly reduce the incidental mortality of this species, and anecdotal data suggest that numbers may be beginning to rebound (1) (5). Nevertheless, either voluntary or imposed seasonal and/or area closures would undoubtedly help further minimise incidental mortalities and greatly aid the recovery of this magnificent and dramatic giant of the sea (3) (6).