Reducing Bycatch

Groundfish include over 90 species of flatfish, roundfish, and rockfish, most of which spend their time near the bottom of the ocean. In the 1970s and 80s, many groundfish populations were devastated by overfishing, especially by deepwater trawls that drag along the bottom, damage seafloor habitats, and collect a variety of nontargeted marine life, or bycatch.

By the 1990s, federal fishery policy changed to demand an end to overfishing, and the U.S. Pacific Fishery Management Council declared ten groundfish species to be overfished. Plans were instituted to immediately halt overfishing of these species and to give them time to recover. This led to the creation, in 2002, of Rockfish Conservation Areas (RCAs) that were closed to bottom trawling, for any fish. One of these RCAs runs the entire length of the California coast along the edge of the continental shelf where it begins to slope downward to the seafloor.

In response, Conservancy scientists partnered with fishermen to find a solution that would work for nature and people.

First, we worked with Moss Landing Marine Laboratories, Marine Applied Research and Exploration, Monterey Bay Aquarium Research Institute, the fishing industry, and agency partners to develop a stereo underwater camera system that would allow us to monitor overfished species. This stereo video lander is lowered down to rocky habitats where overfished rockfish like to congregate, and enables us to collect size and abundance data on many species, especially overfished stocks like cowcod and yelloweye rockfish.

We also collaborated with academic partners, central coast fishermen and regulatory agencies to conduct experimental fishing inside the Rockfish Conservation Areas under a special permit. Instead of trawling, the fishermen used hook and line gear that had been modified.

A comparison of fishing and video surveys revealed that fishermen could fish with the modified gear and catch the abundant species while rarely catching the overfished species, which were known to be present based on the video surveys.  The video surveys provided much- needed information on the abundance, sizes, and habitat associations of the overfished rockfish populations.

This type of cost-effective monitoring approach can help improve the accuracy of stock assessments, inform catch limits and spatial closures with better data, and reduce bycatch of overfished species – and thereby help to maintain the economic viability of California’s fisheries.