Fishery of the Giant Sea Bass
By Michael Domeier, PhD., Pfleger Institute of Environmental Research
 It is widely recognized that fishes that grow slowly and mature at a relatively old age are very susceptible to overfishing. Giant sea bass possess these characteristics (discussed in more detail below) and have suffered a serious decline in numbers. The California Department of Fish and Game (DFG) have kept commercial landings data since 1916 and recreational landings data from 1936.
Commercial landings from US waters peaked in 1932 near 200 thousand pounds before rapidly plummeting (Figure 1). Mexican waters were much more productive, peaking at over 800 thousand pounds in 1932, and did not permanently sink below 200 thousand pounds until 1964 (Figure 1). A few hook and line fishermen targeted black sea bass, but they were also caught incidentally by gill nets set for halibut and white sea bass.
Recreational landings, reported in number of fish rather than pounds, show a similar trend of peaking and permanently declining (Figure 2). The peak in California landings occurred in 1963 while Mexican landings peaked in 1973. The fact that these recreational fisheries peaked after the commercial fishery is due to the later development of the recreational fishery rather than a reflection of the giant sea bass population. A few boats developed a special recreational fishery for giant sea bass that targeted spawning aggregations during the summer months. Trips made in the month of July to certain reefs between Punta Abreojos and Bahia Magdalena consistently produced 70-100 giant sea bass. One trip in particular produced 255 giant sea bass in three days! Once these aggregations were exploited the fishery disappeared with the fish.
A law was passed in 1981 that prohibited the take of giant sea bass for any purpose, with the exception that commercial fishermen could retain and sell two fish per trip if caught incidentally in a gill net or trammel net. This law also limited the amount of giant sea bass that could be taken in Mexican waters and landed in California. A vessel could land up to 1000 pounds of Mexican giant sea bass per trip, but could not land more than 3000 pounds in a calendar year. The law was amended in 1988, reducing the incidental take to one fish in California waters. Although this law may prevent commercial fishermen from profiting from the capture of giant sea bass in California, it did not prohibit fishing over habitats occupied by this species and probably did little to reduce the incidental mortality of giant sea bass. Giant sea bass that were entangled in the nets were simply discarded at sea.
The 1981 rule changes did more to protect giant sea bass in Mexico, since large landings had been historically made by hook and line fishermen targeting grouper, cabrilla and giant sea bass off the Pacific coast of Baja California. The banning of inshore gill nets by Proposition 132, a 1990 public initiative, displaced the California fishery from the majority of areas inhabited by giant sea bass; it is reasonable to assume that this closure significantly reduced the incidental mortality of giant sea bass in California.
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