Numéro du document:
WG-EMM-2023/26
Soumis par:
Martin Collins (Royaume-Uni)
Approuvé par:
Martin Collins (Royaume-Uni)
Point(s) de l'ordre du jour
Résumé
- This paper provides an overview of CCAMLR-related ecosystem monitoring and scientific activities undertaken by the British Antarctic Survey (BAS) during the period April 2022 to March 2023.
- BAS research is focussed on the Scotia Sea region (Area 48) and the 2022/23 season saw very low sea ice (record low in austral summer 2022/23) linked to atmospheric circulation and temperature anomalies, associated with a strong positive phase of the Southern Annular Mode.
- The A76 iceberg which calved from the Filchner-Ronne iceshelf in May 2021 was observed in Subarea 48.3 in April, breaking into smaller fragments southwest of South Georgia in May 2023.
- After an extremely poor season in 2021/22, breeding conditions generally improved at both South Georgia CCAMLR Ecosystem Monitoring Programme (CEMP) sites (Bird Island and Maiviken; Area 48.3) with above average gentoo (Pygoscelis papua) and macaroni (Eudyptes chrysolophus) chick and Antarctic fur seal (Artocephalus gazella) mass and above average penguin breeding success. However, breeding success of black-browed albatrosses (Thalassarche melanophris) was low.
- At Signy Island, South Orkney Islands (Area 48.2) breeding success was above average for chinstrap P. antarcticus and gentoo penguins but the number of fledged Adélie penguins (P. adeliae) was low.
- Gentoo penguin breeding success was low at Port Lockroy, Goudier Island (Area 48.1), possibly due to very heavy snowfall during the breeding season.
- Antarctic krill Euphausia superba was present in predator diets, although was low (24% by mass) in macaroni penguin diets. Krill were generally small except for at Maiviken in summer 2022/23.
- The Polar Ocean Ecosystems Time Series (POETS) Western Core Box (WCB)/Scotia Sea Open-Ocean Biological laboratories (SCOOBIES) research programmes, which focussed on monitoring the ocean and ecosystem near South Georgia using acoustic surveys, biological netting, and mooring arrays equipped with current meters and profilers, sediment traps, acoustic monitoring devices, and temperature/conductivity recorders took place in December 2022 to January 2023.
- The South Georgia Groundfish survey (February 2023) found high biomass of mackerel icefish Champsocephalus gunnari and Patagonian toothfish Dissostichus eleginoides, with two Antarctic toothfish Dissostichus mawsoni also caught during trawling.
- The number of items of beached marine debris was below average at all sites monitored (Bird Island, Signy Island, Port Lockroy) and the number of items of debris associated with seabird colonies (at Bird Island) was around average levels.
- Two Antarctic fur seals entangled in marine debris were observed at Bird Island and four at King Edward Point. Five foul-hooked seabirds were observed at Bird Island: three wandering albatrosses, one black-browed albatross and one grey-headed albatross.