Scripps study: Two key southern California fisheries collapse by CalOceans

Wednesday Sep 28th, 2011 4:16 PM

A new Scripps study has found that two key Southern California fisheries--kelp bass and barred sand bass--have declined by 90% in the past 20 years, continuing an alarming trend that has seen other targeted species like cowcod, sheepshead and halibut dwindling in the region. One proven way to rebuild fisheries is protecting the places where fish feed and breed, and California is working to do just that through the Marine Life Protection Act (MLPA).

A recent study from Scripps Institution of Oceanography found that two critical recreational fisheries—barred sand bass and kelp bass—have collapsed. Populations of these popular sportfish have dropped by 90 percent since 1980, and study authors say overfishing is partly to blame.



So how did the fisheries reach such alarmingly low levels without gaining the attention of state agencies? Because fishing for the two species is concentrated in spawning areas, which gives a false impression of abundance. Huge numbers of fish gather to breed, masking dwindling overall populations. The phenomenon is known as “the illusion of plenty.” Study author Brad Erisman explained it in the San Diego Union-Tribune:



“The problem is when fish are aggregating in these huge masses, fishermen can still catch a lot each trip, so everything looks fine—but in reality the true population is declining.”



The findings are the latest in a worrying trend of California fisheries declines. Assessed species like cowcod and California sheephead are depleted and show little sign of recovery, and a new assessment of halibut indicates its southern California population is deeply depressed.



Fishermen had already noted the decline of halibut. Marina del Rey Anglers canceled last year’s halibut derby, and this year opened it up to other species to allow halibut to recover. Fishermen have also noticed smaller catches of sand and kelp bass. From coverage of the study in the Orange County Register:



"Recreational fishing enthusiasts have seen a decline in barred sand bass, said Dave Elm of Huntington Beach, the chairman of the United Anglers of Southern California.



'We don't get the spawns we used to have 10 years ago on the Huntington Flats,' Elm said."



Reversing the downward trend in California fisheries will require decisive action. In addition to reducing the bag limit and increasing minimum catch size, it is vital the state protects feeding and breeding grounds with the creation of marine protected areas. California is working to develop a science-based network of these underwater parks through the Marine Life Protection Act (MLPA). Studies all over the world have shown the protected ocean areas help to boost fish size and numbers, as well as overall ecosystem diversity and resilience.

