In 2002, Rockfish Conservation Areas were established along the entire U.S. West Coast that prohibit trawl fishing roughly between 185-274 meters depth and the use of commercial fishing gear between 91 and 274 meters depth. This management decision was made in response to overfishing of many slow-growing, vulnerable species in the 1970s and 1980s. These RCAs, along with other management measures, have been successful in reducing the fishing mortality of these at-risk species, but have also limited fishing opportunities on more abundant, less-vulnerable species. Furthermore, these restrictions have constrained the amount of fisheries-dependent data available to evaluate the population status of fished species. Currently, the main fishery-independent method for measuring groundfish stocks is the West Coast Groundfish Bottom Trawl Survey. This survey is limited to low-relief, soft-bottom habitat, and therefore provides little information about rockfish species that inhabit untrawlable, high-relief habitats.
In order to survey the status of populations in untrawlable areas, we have designed a stereo-video camera system to collect fisheries-independent information. We pair video and fishing surveys to evaluate species in high-relief rocky areas.
We conducted one study between San Francisco and Morro Bay to determine the status of overfished stocks in this area as well as to improve the utilization of abundant species while minimizing catches of overfished species. We fished for a total of 58 days and completed 741 sets with hook-and-line fishing gear. We then conducted 299 video surveys in these same locations. Comparisons between our fishing and stereo-video surveys indicated that modified hook and line gear could be used to catch abundant species with limited bycatch of rebuilding species.
To read more about our results, please read our paper in PLOS one:
Targeting Abundant Fish Stocks while Avoiding Overfished Species: Video and Fishing Surveys to Inform Management after Long-Term Fishery Closures
Richard M. Starr, Mary G. Gleason, Corina I. Marks, Donna Kline, Steve Rienecke, Christian Denney, Anne Tagini, John C, Field
Furthermore, we are currently partnering with NMFS to survey untrawlable areas in the same survey blocks selected for trawl surveys. In 2015, we surveyed 11 NMFS survey blocks containing untrawlable habitats and collected 130 video samples. The frequency of occurrence of rebuilding species in NMFS trawl surveys in those 11 blocks ranged from 9–36%, whereas occurrence of rebuilding species in video surveys of the untrawlable portions of the same blocks ranged from 33–83% of the study blocks. The number of individuals of rebuilding species was 2–10 times greater in visual surveys, despite having covered less than 5% of the area covered by trawl tows. Moving forward, we plan to expand our video surveys to the entire PFMC Monterey Groundfish Management Area and demonstrate how video surveys in the untrawlable portions of NMFS Groundfish Survey blocks can be used to improve stock assessments.