Evaluating change in the krill-based food web and developing solutions for the future sampling of krill

The SCAR Krill Action Group (SKAG) provides a conduit for science to feed into the management of the Antarctic krill fishery, as well a more general forum to promote collaboration, help early career researchers, improve understanding of krill biology and ecology, and facilitate information exchange. From 26-30 April 2021 SKAG held a workshop, as a series of five zoom meetings, each of 2 hours, to help achieve these goals. The workshop was hosted and financed by WWF and was attended by around 100 participants each day from 19 countries. The workshop comprised 16 science talks summarising the current state-of-the-art of both traditional and emerging methods to sample and analyse krill, focusing on their ability to observe spatio-temporal change within the krill-based food web. This workshop report summarises the initial findings of the workshop; shares the talk abstracts; results of zoom-polling questionnaires including the early career researcher component; and shows results of the exercises. In summary, this online workshop included sufficient participation to represent the weight of expert opinion of the current krill research community. The talks were multi-authored, also providing the required breadth of perspective - our feedback was that this was particularly welcomed among the ECR community. The numbers attending also provided sufficient sample size for zoom polling; this showed a strong appetite for change in how science was linked to krill fishery management. Change was thought to be best achieved through both the provision of data and improved communication with management, underscoring the relevance of SKAG. Understanding the controls on krill recruitment emerged consistently as a clear priority research topic, with identification of spawning hotspots also a priority in the context of management and conservation over shorter timescales. We had sufficient response (33 replies) for the exercises aimed at a) evaluating longer-term change in krill populations and b) mapping the suitability of old and new sampling methods onto research questions. We are still collating a large response on the former, and this will form one of the sections for the paper that will emerge from this workshop. The second, method mapping, exercise showed consensus that newer methods were particularly valuable to detect change and observe krill behaviour at smaller scales of space and time, but that “traditional” nets and acoustics from research vessels remain hard to replace for longer term-issues such as recruitment variability. This throws down challenges for future krill sampling, through a combination of multiple, complementary and emerging approaches. In addition to the new and emerging approaches described in this workshop, a combined approach to Euphausia superba dynamics will involve data provided by predators, the fishery itself, the fishery as a scientific platform, alongside the continuation of traditional approaches.

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