Retrieval operations of derelict fishing gears give insight on the impact on marine life

Abstract

Abandoned, lost and discarded fishing gear (ALDFG), significantly impacts marine ecosystems and biodiversity by incidental capture known as ghost fishing. Such impacts were quantified during the Norwegian Directorate of Fisheries' annual ALDFG cleanup operation in September 2023 by examining the characteristics of retrieved ALDFG and recording the taxonomically sorted catch abundance and biomass. A total of 307 specimens equaling 382 kg of biomass were caught in the recovered gillnets and king crab pots. Gillnets exhibited a 27.3 % greater catch abundance and 50.3 % higher biomass per ALDFG unit mass compared to king crab pots. Margalef, Menhinick, Simpson, Shannon, and Pielou diversity indices showed a more pronounced impact on species richness and biodiversity associated with recovered gillnets. This study introduces an approach to assess the impact of ghost fishing on ecosystems and biodiversity through ALDFG retrieval operations, instrumental in developing estimates of the total ghost fishing capture by ALDFG.