Mortality and Population Abundance of Three Species of Paralabrax off San Diego, California


In this project, anglers are catching, tagging and releasing calico bass and barred sand bass on chartered sportfishing trips to select sites inside and outside the new South Coast marine protected areas (MPAs), as well as during catch-and-release sportfishing tournaments. Besides tagging fish, they are recording fish sizes, the gears used to catch fishes and evidence of pressure-induced injuries (barotrauma). Samples of bass are also being put in pens and observed to estimate mortality rates from catch-and-release practices. Private boat owners are helping researchers catch, tag and release spotted bay bass, which reside in bays. In addition to the angler data, about 50 barred sand bass will be caught at a spawning aggregation in the new South La Jolla Marine Reserve, surgically implanted with acoustic tags, and tracked via a deployed listening array for up to a year. Data will be used to study fish movement patterns, including “spill over” from MPAs, and to estimate spawning biomasses and mortality rates from predation, fishing and catch-and-release. As of August of 2013, volunteer anglers and researchers had tagged more than 8,500 bass from Imperial Beach north to Long Beach. The scientists also deployed the acoustic hydrophone array. Some of the project's preliminary results suggest that all three bass species are likely to survive catch-and-release and that recaptured fish have relatively small home ranges (i.e., limited movements), with some exceptions. A few barred sand bass tagged in San Diego Bay, for example, were subsequently recaptured off the Tijuana Flats, and one tagged kelp bass traveled from La Jolla to San Clemente in southern Orange County. Scientists say that the continued accumulation of tagging and tracking data will provide highly valuable information for models of marine bass movement, mortality, and stock abundance. Some of the team's outreach activities, to date, have included hosting booths at the annual Fred Hall Fishing and Boat shows, giving talks to local fishing clubs and making themselves readily available to various media outlets.

  • University of California, San Diego, Scripps Institution of Oceanography

Co-principal Investigators

  • University of California, San Diego, Scripps Institution of Oceanography
  • San Diego Oceans Foundation