Juvenile Rockfish Trawl Survey Completed

Scientists from the Fishery Ecology Division completed their annual midwater trawl survey (DSJ-0603) of young-of-the-year (YOY) pelagic juvenile rockfish on June 18 when the R/V David Starr Jordan returned to port in San Diego. The cruise started on May 5 in San Francisco, lasted 45 days, and spanned the California coast from Cape Mendocino to San Diego. Sampling during the survey is designed to measure the reproductive success and year-class strength of winter-spawning species of rockfish (Sebastes spp.), including bocaccio, widow, chilipepper, shortbelly, and canary rockfish. In addition, interannual variability in the distribution and abundance of the epipelagic micronekton community (e.g., krill, squid, sardines, anchovies, and lanternfishes) is monitored and studied.

This year the survey encountered very low catches of YOY rockfishes, similar to results from last year, although in 2005 the survey encountered high numbers of rockfish south of Point Conception, whereas this year there were very few fish caught anywhere. Likewise, catches of krill and market squid (Loligo opalescens) were much lower than normal, suggesting a large scale failure in production from the spring transition to the upwelling season.

The cruise also coordinated sampling efforts with the Pacific Whiting Conservation Cooperative and the F/V Excalibur, which simultaneously conducted a midwater trawl survey using identical sampling protocols from Monterey, CA to Westport, WA. This makes 6 years that the two surveys have coordinated their sampling and it should be possible to link them to produce a set of coast-wide indices of groundfish pre-recruit abundance. A workshop will be held in September at the Santa Cruz facility to further study this issue. (June 20, 2006)