Did bycatch of threatened, endangered, or protected species change?

Indicator: Bycatch

Short Answer: No. There have been no detectable changes in catches of threatened, endangered, or protected species of birds, fish, or marine mammals that can be attributed to the catch share program.

Key Findings

  • No changes have occurred in catches or interactions of threatened, endangered, or protected species with fishing gear that can be unambiguously associated with catch share implementation.
  • Because of the catch share program’s requirement that one hundred percent of catches be monitored at sea by third-party observers, reliable data on interactions with threatened, endangered, or protected species are now available.
  • Interactions and catches of threatened, endangered, or protected species are within safe biological limits, as determined by the National Marine Fisheries Service.
  • Catches of eulachon and green sturgeon have increased recently. Eulachon catches likely reflect increases in their abundance. Green sturgeon catches may reflect a shift in fishing effort towards areas where they are more common.

Interactive Chart Story


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.


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.

Data and Methods

Data were compiled from published reports based on observed trips, provided by the NOAA National Marine Fisheries Service and the Pacific Fishery Management Council. Prior to 2011, observer coverage was between 16 and 25 percent of total estimated trawl hauls. From 2011 onward, nearly one hundred percent of hauls were observed, providing more precise estimates.

Cetaceans, seabirds, and pinnipeds were reported as number of observed interactions, classified as “entanglements”, “lethal removal”, or “killed by gear”.

To estimate fleetwide bycatch in years when only a fraction of the hauls were observed, we fit a statistical model to estimate the average encounter rate per haul, and then propagated uncertainty in the encounter rate to the unobserved hauls. Note that this calculation propagates only the uncertainty in the average encounter rate per haul and does not include uncertainty due to random chance events during the unobserved hauls. This calculation was not necessary for Chinook salmon and eulachon because total fleetwide catches for these species were estimated independently.

Information Sources

Retrieved from Pacific Fisheries Management Council website, 5/7/2017

Green Sturgeon: F5a_NMFS_Rpt5_ElectricOnly_Green_Sturgeon_Bycatch_rpt_2017_Apr2017BB.pdf, retrieved from Pacific Fisheries Management Council website, 5/7/2017

Chinook Salmon: Somers, K. A., M.A. Bellman, J.E. Jannot, Y.W. Lee, J. McVeigh, V. Tuttle. 2014. Observed and estimated total bycatch of salmon in the 2002-2013 U.S. west coast fisheries. West Coast Groundfish Observer Program. National Marine Fisheries Service, NWFSC, 2725 Montlake Blvd E., Seattle, WA 98112.

Marine mammals and seabirds and observer coverage: Northwest fishery science center Protected Species Reports, https://www.nwfsc.noaa.gov/research/divisions/fram/observation/data_products/protected_species.cfm. Accessed 5/7/2017. Marine Mammal, Seabird, Sea Turtle observed bycatch (2002-2014)

Sommers, K.A., Lee, Y-W, Jannot, J.E., Whitmire, C., Tuttle, V.J., McVeigh J. 2017. Fishing effort in the 2002 – 2015 Pacific Coast Fisheries. F5a_NMFS_Rpt1_ElectricOnly_FishingEffort_rpt_2017_Apr2017BB.pdf. Retrieved from Pacific Fisheries Management Council website, 5/7/2017

National Marine Fisheries Service, 2012. Endangered species act (ESA) Section 7(a)(2) Biological Opinion and Section 7(a)(2) ”Not likely to Adversely Effect” Determination. PCTS Number: NWR – 2012 – 876

Holland, D.S. and Norman, K. 2015. The anatomy of a multispecies individual fishing quota (IFQ) “market” in development. U.S. Dept. of Commer. NOAA. NOAA Technical Memorandum NMFS-S/SPO-158, 30.

Updated: April 2018

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