Winter Krill at South Georgia
Resolving ecosystem effects of the South Georgia winter krill fishery
- Start date
- 1 December, 2021
- End date
- 31 May, 2024
The Winter Krill project is a Darwin Plus project, funded by Defra, and its activities are focussed on South Georgia (SG), which is part of the UK Overseas Territory (OT) of South Georgia & the South Sandwich Islands .
The overarching objective of the project is to obtain information on i) the distribution and abundance of Euphausia superba (Antarctic krill) during the winter; and ii) overlap between the distribution of krill-dependent predators and krill in the fishery area. The motivation behind this is that the commercial krill fishery around SG operates exclusively during the winter period, yet information on the stock dynamics and distribution of krill during this period are sparse. Although MPA restrictions include a 30 km no-take zone around the SG coast, there is evidence to suggest that the foraging habits of krill-dependent predators such as penguins and seals vary depending on the abundance of krill, and that this may result in overlap between them and the krill fishery, particularly during low krill years. There is also evidence of baleen whales returning to SG in large numbers during the summer and of some remaining during the winter, with the increased prey demand potentially further increasing competition for krill resources.
The information gathered throughout this project will directly inform fisheries management by feeding into the CCAMLR initiative to develop a more dynamic management approach for the krill fishery. This requires data on krill biomass and predator distribution so that a spatial allocation of catches, based on the krill demand of predators, can be developed. The project will run for 2.5 years, from 1st December 2021 to 31st May 2024. Core activities include acoustic surveys of krill distribution and biomass, gentoo penguin tracking, and cetacean observation, detailed further below. We will also work closely, and share outputs, with all our interested stakeholders.
To gather data on krill, acoustic surveys that extend within and outside the MPA no-take zone will be undertaken during the austral winter period in two consecutive years (2022 and 2023). Surveys will take place in May, July and September of each year corresponding to the start, middle and end of the fishing season. The survey transects (shown in the map in Fig. 1) are based on those surveyed historically as part of the Eastern Core Box (ECB) surveys and approximately 4 transects will be selected to correspond to the areas of greatest coincidence with the krill fishery. Comparative summer surveys will also be carried out by BAS. Surveys will be carried out on the SG Fisheries Patrol vessel, the Pharos SG, which will have 38 kHz and 120 kHz transducers installed by the GSGSSI for the purposes of the project. In addition, the Western Core Box (WCB) has been operated by BAS from 1996 to present and will continue to run throughout the course of this project, giving us useful contextual and comparative data.
To gather data on predator distribution and potential overlap with the krill fishery, gentoo penguins will be tracked from April in each of the two survey years, from two locations on SG (Bird Island and Maiviken) that have differing proximities to the krill fishing grounds. This will provide high resolution data on habitat use of the penguins during the fishing season, and will be complemented with data on subsequent reproductive performance that is gathered as part of the regular penguin monitoring work carried out by BAS. Seabird and marine mammal observations will be conducted using JNCC observation methods during all of the surveys to gather data on distribution and abundance in relation to krill. Detailed cetacean surveys will also be conducted by specialist marine mammal observers during the July surveys of each of the two survey years.
Core staff involved in the project are Prof Martin Collins (PI), Dr Sophie Fielding, Dr Jen Jackson, Dr Cecilia Liszka, Prof Eugene Murphy, Dr Norman Ratcliffe, Prof Geraint Tarling and Prof Phil Trathan (all BAS), Susannah Calderan and Russell Leaper (specialist cetacean observers) and Klemens Pütz (Antarctic Research Trust).
Fig.1: Map of part of the South Georgia and South Sandwich Islands Marine Protected Area (SGSSI MPA) showing the Eastern Core Box survey transects that will be occupied during the project, and the Western Core Box survey (WCB) regularly occupied by BAS. Also indicated on the map are the no-take zones where fishing is prohibited, including a 30 km distance from the SG coastline and a 12 nm (22.2 km) distance from the coastline of Clerke and Shag Rocks. Credit: Cecilia Liszka
Competition between fisheries and predators is a global conservation issue and mitigating it requires an ecosystem-based approach to fisheries management. Whilst the South Georgia krill fishery is restricted to winter, information on stock dynamics and predator foraging is sparse. We will address this by:
- Quantifying the abundance and distribution of krill around South Georgia during winter;
- Assessing predator distribution and foraging during the winter in the fishery area
Through this project we aim to obtain an understanding of the winter distribution of Antarctic krill around South Georgia, and the potential impacts of the krill fishery on krill-dependent predators including penguins and cetaceans. In turn, this will facilitate ecosystems-based management of the krill fishery.
Ecosystem CCAMLR Lead Scientist
Susannah Calderan (Consultant)
Susannah Calderan is a research fellow at the Scottish Association for Marine Science (SAMS), and specialises in large whale ecology, particularly passive acoustic monitoring. As part of Australian Antarctic Division and BAS research teams, she has developed new techniques for acoustically detecting and tracking whales in the Southern Ocean, in particular Antarctic blue whales. Susannah has participated in several Antarctic and sub-Antarctic voyages over the last ten years. She has also worked on baleen whale acoustics, including blue, fin, Bryde’s, and sei whales in the Pacific, Atlantic and Indian Oceans. Susannah also works with NGOs, Universities and governmental organisations in the UK, Europe and US, developing new visual and acoustic survey and analysis techniques for localising and tracking cetaceans at a range of spatial scales, and also working on anthropogenic impacts on whales such as fisheries bycatch, underwater noise and aquaculture.
Russell Leaper (Consultant)
Russell Leaper studied mathematics at Oxford University before joining the IFAW research vessel Song of the Whale in 1988 to study sperm whales. He initially worked on developing acoustic methods to study and count whales. His subsequent research has covered a wide range of marine mammal conservation and welfare issues with an emphasis on survey methods and population assessment. In addition to data analysis he has conducted extensive field work from a range of vessels including several surveys around South Georgia and elsewhere in the Southern Ocean. Russell has been a member of the Scientific Committee of the International Whaling Commission since 1996 and attends as a member of the UK delegation. He has authored over 50 scientific publications and presented more than 60 papers at international conferences. He also has an MSc in Marine Resource Development and Protection from Heriot-Watt University.
Contact: [email protected]
All data derived from the project will be archived with the UKRI Polar Data Centre (PDC). Data will also be linked to the GSGSSI Data Portal which was funded by a previous Darwin Plus grant. Information and data visualisations e.g. penguin tracking data, will be made available as soon as possible on the BAS website.