Metrics

This indicator measures the number of marine mammals, seabirds, and sea turtles that are caught or killed per day by fishing vessels when third-party observers are on board to monitor interactions.

Analysis

Bottom and midwater trawl gear captures, entangles, or kills several species of marine mammals, seabirds, and fish that are afforded special legal protection. As such, these species cannot be landed, and if the number of their interactions with fishing gear exceeds the number deemed to be within biologically safe limits by the National Marine Fisheries Service, the fishery may be forced to suspend operations. Consequently, the fishing industry has an incentive to avoid these interactions as much as practicable.

Because catch share programs eliminate the race to fish, they might enable fishermen to better avoid threatened, endangered, and protected species by adjusting the timing and locations of their fishing activity. Alternatively, shifts in the timing or location of fishing effort (Fishing Effort Indicator) after a catch share program is implemented may inadvertently increase overlap of fishing and species distributions, and might therefore increase encounters.

We analyzed data to determine whether estimated fleetwide bycatch of marine mammals (pinnipeds and cetaceans), seabirds, salmon (largely Chinook salmon), eulachon, and green sturgeon changed following the implementation of the catch share program in 2011.

Across all of these groups, we found no evidence of a change in encounters with these species that was unambiguously associated with the 2011 catch share implementation. Pinniped interactions fluctuated without trend, showing a peak in 2009–2010 (largely due to an increase in Steller sea lion interactions) and then declining to average levels from 2011 onwards. Cetaceans and seabirds were rarely encountered throughout the baseline and catch share years (the latter particularly after 2006). Chinook salmon bycatch dropped from a high of more than 14,000 individuals annually in 2002 and 2003 to levels fluctuating between 50 and 400 individuals annually in the subsequent years.

Two protected fish species, green sturgeon and eulachon, were captured in increasing numbers in most of the later years of the study period. For eulachon, the increasing catch may reflect an increasing abundance of the species. The cause of the increase in green sturgeon catch is not as clear. Sturgeon populations do not increase as rapidly as do eulachon, so it is unlikely that population abundance was contributing to the large increase apparent from 2009 onward. Almost all green sturgeon bycatch was occurring in coastal areas offshore of Oregon, suggesting that the increase in green sturgeon catch was possibly linked to a shift in location of trawling effort with proportionally more effort occurring near the Columbia River and Astoria (Sommers et al. 2017). Because green sturgeon catches peaked well before the catch share program and then fluctuated without trend, the observed increase was unlikely due to the program. However, quota has moved out of California and concentrated in Washington and Oregon (Holland and Norman 2015), and this geographic shift in fishing effort might explain any future increases in interactions.

Interactions with Stellar sea lions, eulachon, and green sturgeon were below the levels deemed by the National Marine Fisheries Service to jeopardize these Endangered Species Act-listed species (National Marine Fisheries Service 2012).

Possibly the most notable effect of the catch share program with regard to bycatch was the increased precision of estimated catches and interactions. Prior to the catch share program, less than one quarter of all landings were monitored by independent observers, requiring statistical estimation of total catches and interactions. The catch share program requires one hundred percent observer coverage, removing the uncertainty caused by statistical extrapolation.