Safeguarding Antarctic krill stocks for baleen whales

This Darwin Plus funded project aims to improve our understanding of how Antarctic krill, foraging whales and the krill fishery interact in space and time, to improve krill fishery management and better conserve krill-based ecosystems.

Antarctic krill (Euphausia superba) are a key species in the Southern Ocean ecosystem. These small crustaceans are one of the most abundant animals on earth and are a major food source for many higher predators including penguins, seals and baleen whales. Antarctic krill are also the focus of a commercial fishery.

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) manages the krill fishery with an ecosystem approach, where krill stocks should be maintained at productive levels and fishing activities should not interfere with krill-dependent consumers. However, krill fishery management is conducted at large spatial scales, but fishing activity tends to be more concentrated. CCAMLR will not allow the krill fishery to expand without the implementation of management procedures that considers these differences in scale. Currently CCAMLR plans to implement finer scale management procedures by conducting and linking three areas of research 1) krill stock assessment 2) krill growth models and 3) spatial overlap analysis, which includes the prey consumption and location of foraging whales.

To conserve biodiversity and improve protection of natural environments, we need a better understanding of how whales, Antarctic krill and the krill fishery interact in space and time. This is especially important as baleen whale populations are recovering from historical exploitation and climate change is affecting krill distribution.

The Safeguarding Antarctic krill stocks for baleen whales project aims to improve our understanding of the interactions between foraging whales, Antarctic krill and the fishery, and provide information to CCAMLR to improve krill fishery management and conserve krill-based ecosystems.

Research objectives:

We will conduct fieldwork to deploy biologging tags and conduct prey surveys in the Western Antarctic Peninsula region, over two austral summers/autumns (early 2024 and early 2025).

1. Whale foraging behaviour and distribution will be measured using biologging tags, with a particular focus on fin whales – a significant but poorly known consumer of krill. Whales will be tracked using two kinds of tags: 1) CATS tags which provide high resolution, fine scale information on the three-dimensional behaviour of whales, and 2) LIMPET tags to provide longer-term information on the location and behaviour of whales.
2. Krill swarm distribution will be measured using active acoustic echosounder surveys. Echosounder surveys will be conducted from a yacht-mounted echosounder, supplemented by an autonomous surface vehicle (ImpYak) also carrying an echosounder, to map the three-dimensional structure of prey fields. These small platforms will enable us to survey near-shore areas safely, areas that are not possible to study using larger research vessels.
3. Krill fishing vessel distribution and behaviour will be obtained from CCAMLR and Global Fishing Watch. These will be used to locate the fishing vessel activity and model forecasts of overlap among krill, whales and fisheries.

By analysing this fine-scale spatiotemporal distribution of krill, baleen whales and fisheries, we aim to understand predator-prey dynamics that are uniquely relevant to the scales of operation of the fishery and the ecosystem.