Sharks, Seabass Rebound After Fishing Banned
Scientists have wondered whether long-lived fish that reproduce slowly can overcome a population collapse. Now an analysis of the effects of fishing restrictions in California finds an encouraging increase in seabass and sharks. Big fish have returned to California's southern coast following a 15-year ban on gill net fishing.
The numbers of marine fish making a living as predators at the top of the food-chain dropped dramatically during the last century. Southern California's commercial fishery once enjoyed huge landings of white seabass. By the early 1980s, that fishery had crashed to just 10 percent of what was brought ashore in the 1930s. Giant seabass, the apex predator in this marine ecosystem, had previously disappeared from the commercial catch. Soupfin sharks were already scarce in the early 1940s from over-fishing, while leopard sharks began noticeably declining in the mid-1980s.
In a drastic and controversial move to save the fish, gill nets were banned as of 1994 from within three miles of southern California's mainland. The new fishing restrictions spared spawning seabass aggregations along rocky headlands and shark pupping in kelp beds.
It took only three years for distinct improvements in fish stocks to appear. All four species responded to the release from fishing.
Leopard sharks increased their numbers by 15 percent a year, and the soupfin shark population also grew significantly. White seabass thrived and by 2003 the fishery, now operating offshore, had recovered to historical its catch. Perhaps the biggest surprise came in 2002, when scuba divers spotted giant seabass in the region for the first time in 28 years.
Daniel J. Pondella II and Larry G. Allen. 2008. The decline and recovery of four predatory fishes from the Southern California Bight. Marine Biology. 154(2): 307-313.