Changes in long-lived rockfishes after more than a decade of protection within California's largest marine reserve

摘要

In 2001, the Pacific Fishery Management Council established 2 large (10878 and 260 km(2)) Southern California Bight marine reserves called Cowcod Conservation Areas (CCAs) in response to declining abundance of west coast rockfishes, particularly overfished cowcod. Following closure, no fishery-independent monitoring took place for groundfishes within the CCAs through 2013. To assess the impact of the closures, we sampled multiple sites inside and outside CCAs from 2014 to 2016 via the Northwest Fisheries Science Center's Hook and Line Survey. We investigated variations in catch per unit effort (CPUE), size, length frequency and percent of sites with positive catch for 14 abundant groundfishes (bank, bocaccio, chilipepper, copper, cowcod, greenspotted, lingcod, olive, rosy, speckled, squarespot, starry, swordspine and the vermilion-sunset complex). General linear models that included area, year, depth and distance from port revealed significantly greater CPUE inside CCAs for 11 species. CPUE for lingcod, copper rockfish and vermilion-sunset was significantly or near-significantly lower inside the CCAs. We saw significant or near-significant differences in size (12 species) and length-frequency distributions (10 species), with larger fish present inside CCAs. The percentage of sites positive for individual species tended to be greater inside CCAs (11 species). We also observed significantly elevated species richness (species per site) and total CPUE inside CCAs. Results indicate larger individuals and greater CPUE for multiple rockfishes inside CCAs either as a result of effective management or perhaps pre-existing conditions.