The ecosystem approach to management of the Antarctic krill fishery – the ‘devils are in the detail’ at small spatial and temporal scales
Fishery demand for Antarctic krill is increasing, and projected to continue increasing into the future. Krill has the potential to contribute approximately 10% to all future marine landings, adding significantly to global food security. However, the fishery is effectively data-limited so is currently managed using precautionary assessments that relate to large spatial and temporal scales that preclude the need for fine-scale ecological data. To respond to recent changes in fishery operation and to mitigate possible ecological impacts, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) plans to revise its management strategy so that it takes into account ecosystem operation at smaller spatial and temporal scales, such as those relevant to krill-dependent predators. Here, we consider how catches in coastal areas potentially present challenges for these predators, where cumulative catches over the fishing season can sometimes be greater than local consumption by predators, and sometimes greater than the standing stock of krill within an area because of krill transport and replenishment by ocean currents. Protecting feeding areas used by land-based predators such as penguins and seals, whilst also offering a high level of protection for pelagic predators such as some species of fish and recovering populations of cetaceans, will require innovative solutions. We highlight critical ecological research needed to reduce management uncertainty. This is important as we demonstrate that krill consumption by predators in near-shore coastal habitats relies absolutely upon krill movement and oceanographic transport. We also highlight the need to improve understanding about krill behaviour, especially in relation to observed seasonal changes in krill biomass. Finally, we highlight that without up-to-date data about changes in krill, krill-dependent predator populations and their oceanographic environment, management will remain challenging in the context of increasing fishing pressure, recovering populations of marine mammals and a changing climate.
Authors: Trathan, P.N. ORCID record for P.N. Trathan, Warwick-Evans, V. ORCID record for V. Warwick-Evans, Young, E.F. ORCID record for E.F. Young, Friedlaender, A., Kim, J.H., Kokubun, N.