Bycatch in the West Greenland lumpfish fishery, with particular focus on the common eider population

Abstract

Incidental bycatch is a well-known challenge in gillnet fisheries throughout the world, and the fishery for North Atlantic lumpfish Cyclopterus lumpus roe is no exception. In Greenland, the fishery was Marine Stewardship Council-certified in 2015 but has pending conditions related to bycatch quantification, enforcement and mitigation strategies. To improve this situation and to assess the potential impact of bycatch, we collected independent on-board observer data on non-target fish and seabirds over 2 seasons (2019 and 2021). We recorded 6 fish species, but the only species constituting >1% of the lumpfish landings was the spotted wolffish Anarhichas minor. The bycatch of fish likely had little impact on the involved fish stocks. We recorded 4 seabird species, of which common eider Somateria mollissima was most common. When extrapolated to the entire West Greenland lumpfish fishery, the estimated bycatch of common eider was considerably higher in 2019 (19938; 95% CI: 3486-59661) than in 2021 (9802: 1260-29940) due to a longer fishing season in 2019. On average, for 2019 and 2021, the bycatch was modelled to reduce the growth potential for the West Greenland winter population by 51%. In comparison, the current hunting level (16538 birds yr-1) reduced the growth potential by 30%. The larger impact of bycatch was mainly due to a larger proportion of adults and females being targeted. The common eider bycatch impacts mainly the breeding population in Canada and Southwest Greenland and less so in Northwest Greenland. As mitigation, we recommend temporal closures of the fishery unless modified gillnets, which markedly reduce bycatch, become available.

Bycatch mitigation in the West Greenland lumpfish ( Cyclopterus lumpus ) fishery using modified gillnets

“…Therefore, future initiatives to implement the modified nets cannot be expected to have general fisher support. However, the annual common eider bycatch in this fishery is estimated to be as high as 20 000 birds for all of Greenland and it has a pronounced effect on the total Greenland winter population, which is a mixture of birds breeding in Canada and Greenland [ 5 ]. Therefore, relatively simple initiatives that potentially reduce the bycatch substantially should be considered from a conservation perspective.…”

“…Wolffish forage strictly along the seafloor, and the small-meshed net addition does not capture these large fish. The overall annual bycatch of spotted wolffish in the lumpfish fishery is estimated at less than 200 tons [ 5 ] but while this presumably has little impact on the stock it does illustrate the effect net modification can have, if implemented correctly. Atlantic halibut has been reported as a bycatch in the Greenlandic lumpfish fishery [ 5 ].…”

“…The overall annual bycatch of spotted wolffish in the lumpfish fishery is estimated at less than 200 tons [ 5 ] but while this presumably has little impact on the stock it does illustrate the effect net modification can have, if implemented correctly. Atlantic halibut has been reported as a bycatch in the Greenlandic lumpfish fishery [ 5 ]. It is IUCN red listed as ‘Endangered’ globally and should be given particular conservation considerations [ 29 ].…”

“…The birds get entangled when diving, making species such as eiders, auks, murres and other seaducks particularly vulnerable. The North Atlantic lumpfish gillnet fisheries are no exception to this problem, with seabird bycatch being reported from all the major fisheries: Norway [ 2 ], Iceland [ 3 ], Canada and Greenland [ 4 , 5 ]. Besides biological consequences for bird populations, the bycatch has economic ramifications for lumpfish fisheries if the fishing industry fails to maintain MSC certification.…”

“…In the North Atlantic lumpfish fisheries, common eider ( Somateria mollissima ) is a key bycatch species [ 4 ], and in Greenland, it is by far the most common, with estimated annual bycatch numbers around 10 000–20 000 individuals [ 5 ]. Common eider, and other seabirds, forage by the aid of sight along the seafloor at depths down to approximately 40 m [ 11 ].…”