Ground-Truthing RCA Models of Overfished Species

Lander_DK

Currently, the west coast groundfish fishery is highly constrained by the Rockfish Conservation Area (RCA), a depth-base closure established in 2002 to help reduce the bycatch of overfished species.  However, the RCA also constrains fishing opportunities for abundant target stocks.

In an effort to assess the effects that the RCA has had on local rockfish populations, the Fisheries & Conservation Biology Lab at MLML is working with commercial fishermen and scientists from the Nature Conservancy, National Marine Fisheries Service, California Department of Fish and Wildlife, and the Environmental Defense Fund to ground-truth predictive maps that model the distributions, abundances, and sizes of overfished groundfish stocks along the west coast.

We worked with engineers at Marine Applied Research and Exploration (MARE) to design and build a rotating, stereo video lander

The overarching objectives of this study are to conduct visual surveys and use directed fishing techniques to assess encounter rates with overfished species (OFS) from a subset of locations within the RCA.

To accomplish this, we:

  1. Use the combination of existing fisheries independent and dependent data and local knowledge to develop predictive maps of the distribution, abundance, and size of overfished groundfish stocks along the entire West Coast.
  2. Ground-truth the predictive maps by performing scientifically-rigorus sampling (visual surveys and directed fishing) to assess encounter rates with OFS in a subset of locations inside the trawl and non-trawl RCAs in central California with predicted high, medium, and low density of OFS.
  3. Characterize the abundance, length, and habitat associations of OFS in those same locations, as well as collect biological samples of OFS for growth and maturity studies.

This work is gathering new data on the distributions and abundances of both rebuilding and healthy fish populations, and expects to provide greater flexibility for management with more fine-scale spatial information.

Click here for project data.  Click here for 2013/2014 project updates.  Click here for project photos.

MARE Engineers working on the Lander body