Determining Sources of Northern Fulmar Bycatch in U.S. North Pacific Groundfish and Halibut Fisheries
Northern Fulmar Bycatch
During fishing operations, sometimes animals are accidentally caught that are not the target species. This is called bycatch and can include marine mammals, seabirds, fishes, and sea turtles. Collecting animals caught as bycatch can help scientists and managers understand the potential impacts of bycatch, as well as give insights into the ecology of the species.
NOAA’s Alaska Fisheries Science Center (AFSC) and Southwest Fisheries Science Center (SWFSC), the University of California Santa Cruz (UCSC), and Oikonos collaborate to collect Northern Fulmars caught as bycatch in the North Pacific groundfish and Pacific Halibut Fisheries, collect genetic samples, and determine the source colonies of the fulmar bycatch. This helps managers understand which colonies are most vulnerable and whether bycatch has an impact on the genetic diversity of the species.
Bycatch is a principal conservation concern for many marine vertebrates and seabirds are especially vulnerable because they are generally long-lived and late maturing, with low reproduction rates. In Alaska, were bycatch of seabirds has long been a recognized issue, fishery managers have successfully worked with the North Pacific groundfish and Pacific halibut fisheries to reduce seabird bycatch through use of mitigation techniques such as streamers. The North Pacific Observer Program, which covers these fisheries, monitors and collects seabirds caught as bycatch for research and conservation purposes.
Although these fisheries have greatly reduced seabird bycatch, Northern Fulmars are frequently caught in these fisheries, with an average of 4,110 birds caught annually (2007-2017). This species, which has a circumboreal distribution and breeds on remote islands in Alaska, numbers ~1.5 million birds in the region.
Through our partnership with AFSC, we have examined thousands of fulmars from these fisheries since 2008 and collected genetic samples from each one. In 2017, with funding from the North Pacific Research Board, we partnered with J. Carlos Garza and Diana Baetscher at UCSC and SWFSC to study the genetic origins of fulmar bycatch through genetic stock identification, and investigate the population structure of the species in the region. To help create genetic baseline markers from each of the primary four colonies in Alaska, researchers Andy Ramey and Scott Hatch provided fulmar genetic samples collected by US Geological Survey on the colonies. We used markers developed from these samples to then link fulmars caught as bycatch back to their colonies-of-origin. Next, we determined whether fulmar mortality from bycatch was proportional to colony sizes, or whether certain colonies had disproportionately more or less bycatch originating from it.
We successfully sequenced genetic samples from fulmars sampled at the four colonies and used these samples to calculate genetic differentiation between the colonies. Using these samples samples, we designed microhaplotype markers to link individual fulmars back to natal colonies. We then sequenced 1,536 fulmars caught as bycatch and assigned them to one of the four colonies using these markers. Across the colonies, we found low genetic differentiation (or weak population structure). Genetic assignment of bycatch samples identified disproportionately more bycatch originating from the Pribilof Islands relative to the population size of the colony, and proportionately less bycatch from Chagulak Island. While the lack of genetic differentiation suggests that bycatch has a minimal impact on overall genetic diversity of Pacific fulmars, estimates of gene flow are limited by post-Pleistocene population expansion, and further study is needed to investigate potential ecological impacts of disproportionate take from Northern fulmar colonies.
This study will continue investigating the genetic origin of Northern Fulmars and genetic questions of the species in the region. Next steps include linking our findings with fishery data to answer questions about Northern Fulmar movements in the region, fulmar-fishery dynamics, and larger ecological questions.
Outreach & Education
To disseminate our findings and support seabird education efforts in the Alaska region, we partnered with Ann Harding of Auk Ecological Consulting and the Seabird Youth Network, and Pam Goddard of Thalassa Education to support seabird curriculum and summer camps developed for Bering Sea communities. Portions of the work will be translated into Russian for use by seabird summer camps in the Commander Islands. Links to our collaborative work are below:
Oikonos also worked with the Alaska Fisheries Science Center to distribute our findings to Alaska’s fishing communities, through events such as ComFish in Kodiak, and the Pacific Marine Expo in Seattle.
University of California Los Angeles
Olga Belonovich, Kamchatka Research Institute of Fisheries and Oceanography
Northern Research Technical Assistance Center (NORTAC)
CDFW-OSPR Marine Wildlife Veterinary Care and Research Center
NOAA Fisheries Alaska Fisheries Science Center