(Alaska Beacon) - Bycatch, the incidental catch of untargeted species in commercial fisheries, is not just about salmon, crab and other fish. Seabirds are also caught and killed unintentionally in fishing gear.
A newly released annual report from the National Oceanic and Atmospheric Administration shows some mixed but mostly positive trends for bycatch of birds in Alaska halibut and groundfish harvests.
Overall, 4,509 birds were killed through bycatch in those fisheries in 2021, a little over two-thirds of the annual average of 6,592 reported from 2011 to 2020, according to the report from NOAA’s National Marine Fisheries Service. A likely factor in the relatively low bycatch total was the decline in overall fishing trips connected in part to the lingering COVID-19 pandemic, the annual report said. The total of 12,873 recorded trips conducted in these fisheries last year was lower than any annual total from 2011 to 2020. In contrast, the highest number of fishing trips in the period was 19,246 recorded in 2016, and that was also the year with the most seabirds killed in bycatch in the period, nearly 10,500, according to the report.
Another factor likely affecting total seabird bycatch is a trend among sablefish harvesters to switch from longline gear to pot gear. Longline fishing uses baited hoods that are lowered into the water, while pot gear is essentially a type of fish trap. Harvesters have been switching to pot gear to prevent whales from eating hooked fish, but the move has an added benefit for birds, the report said. Seabirds are much less likely to become killed by pot gear than by entanglement in longline gear, it said.
Bird bycatch is recorded by designated observers on fishing vessels and through electronic monitoring, the report said.
A potentially troubling sign noted in the report was the high level of bycatch among one type of bird: shearwaters.
More than half of the reported seabird bycatch deaths in 2021 were among shearwaters. That bycatch coincided with a 2021 seabird die-off that was dominated by shearwaters, and it was consistent with prior years’ patterns, in which die-off and bycatch numbers were even bigger.
Warming ocean temperatures may be at play, the report said. “It is believed that changing ocean conditions resulted in depleted food resources for shearwaters causing them to more aggressively target fishing vessels and fishing bait,” it said.
Seabird bycatch occurs mostly in the longline fisheries, a contrast to bycatch of salmon and other untargeted fish, which is a problem in trawl harvests.
Seabird bycatch is important to fishery management because of the risks to endangered, threatened or depleted species.
Short-tailed albatrosses, long-distance travelers that breed almost exclusively on one Japanese island, are of special concern. Deaths of even a few of those endangered birds could trigger fishery shutdowns. In the early 2000s, the fishing industry began using gear modifications to prevent albatross bycatch.
There were no reports of short-tailed albatrosses killed in the 2021 fisheries, the NMFS report said. The two short-tailed albatross deaths in 2019 were the first such events in Alaska waters since 2014, it said.
There were about 400 albatrosses of other species killed through bycatch in 2021, the report said. Those were black-footed and Laysan albatrosses, classified by the U.S. Fish and Wildlife Service as species of concern. There were no 2021 cases of bycatch deaths to threatened Steller’s eiders or spectacled eiders, the report said.
The annual seabird bycatch report followed one released earlier in the year that tracked non-hunting human-caused deaths and serious injuries to NOAA-managed marine mammals. That report showed that from 2016 to 2020, Steller sea lion entanglements in fishing gear dominated the unintended marine mammal deaths, consistent with previous years’ patterns.