Evaluation of collaboratively developed management measures to reduce coral and sponge bycatch in a fully monitored multispecies trawl fishery

Abstract

To protect cold-water corals and sponges from fishing damage, management changes were made in 2012 to the groundfish bottom trawl fishery British Columbia, Canada. The Groundfish Trawl Habitat Agreement restricted the spatial footprint of the fishery and introduced a cold-water coral and sponge bycatch quota, which was among the world’s first. Using 12 years of catch records from the fishery, we found a 31% decrease in overall frequency of encounters of cold-water coral and sponge, a 76% decrease in mean catch weight, and an 89% decrease in total annual catch. We tracked changes in the relative utilization of fine-scale fishing grounds (“fishing opportunities”) and found evidence of active avoidance of areas with high cold-water coral and sponge density. The habitat agreement appears overall to have been successful at reducing impacts to cold-water coral and sponge, although we identified several areas of potential conservation concern where effort and catch have not decreased. Nonspatial management measures in a complex multispecies fishery can result in spatial changes in fishing behaviour, with positive conservation outcomes for bycatch species.