Climate change will alter the structure and functioning of Southern Ocean ecosystems, affect the ecosystem services they provide, and therefore require development of conservation and management strategies. A collaborative Workshop between the Integrating Climate and Ecosystem Dynamics in the Southern Ocean (ICED) programme and CCAMLR brought together a range of ecologists, physical and ecological modellers and fisheries scientists to consider the potential impacts of climate change on Antarctic krill in Area 48. The key outcomes of the Workshop for SC-CAMLR include:
- Area 48 is a region of high natural variability and scenarios of future changes in physical, chemical and ecological drivers are highly uncertain. Global climate models do not currently resolve key ocean and sea ice processes at scales relevant to predictions for Area 48;
- The position of the Polar Front is highly constrained and is not expected to change by 2100;
- Under a high emissions scenario the warming and loss of sea ice is expected to result in a reduction in the abundance and biomass of krill in northern areas of the Scotia Sea but an increase in abundance to the south around the Antarctic Peninsula and Weddell Sea. However, the resilience and adaptive capacity of krill to withstand such changes is poorly determined;
- The combined effects of changing sea ice and krill abundance will result in shifts in the distribution of the various krill-dependent species, with more polar species constrained farther south. These changes are also likely to result in substantial changes in the structure of the food web that may occur rapidly as particular biological thresholds are reached;
- CCAMLR would benefit from investment in the development of high-resolution physicalbiological models and improved models of krill recruitment processes, underpinned by mechanistic understanding to resolve recruitment processes during the winter and the role of sea ice;
- Sufficient data are available to underpin the scenarios from this workshop. Uncertainty around the susceptibility of krill in Area 48 to future climate change can and should be incorporated into projections in order to scope potential outcomes for krill;
- Existing models and approaches developed for Area 48 to assess potential impacts and risks of fishing on krill and the dependent predators are a useful basis for developing models that can incorporate the implications of climate change in a precautionary approach into CCAMLR management.
The Workshop noted the importance a joint approach between ICED and CCAMLR to improve scenarios and ecosystem models and develop quantified model projections of ecosystem change in support of decision making for conservation and management.