Working Group on Marine Mammal Ecology (WGMME)

Two terms of references were standing ToRs; under the first of these, ToR A, new and updated information on seal and cetacean population abundance, population/stock structure, manage-ment frameworks as well as anthropogenic threats to individual health and population status were reviewed. The latest abundance data on harbour, grey and ringed seals are also reviewed under this ToR along with findings on threats to marine mammals such as bycatch, pollution, marine debris and noise.ToR B arose to facilitate the work of WGBIOIV’s ToR A; “Investigate mechanisms linking trophic guilds under contrasting levels of pressure and/or primary production in case study areas”. The initial focus of work should be on harbour porpoise, grey seal and harbour seal in the North Sea as a case study and, therefore, a number of recent studies addressing diet, foraging distribution and trophic interactions were reviewed. Additionally, an overview of published and un-published data on diet and distribution of marine mammals in the North Sea was synthesized.ToR C was implemented to review aspects of marine mammal-fishery interactions not covered by ICES WGBYC. In 2020, WGMME focused its efforts on i) reviewing conservation objectives with respect to maximum mortality since the lack of conservation targets was identified as hin-dering the ability to address marine mammal-fisheries interactions, ii) assessing the use of stranding records as a source of information to identify abnormal mortality and possible rela-tions to fisheries. A country-by-country review of current stranding network activities was in-cluded.ToR D, updating the database for seals, is the second standing term of reference. The database format generated in 2019 was updated with the most recent data on seal abundance.