Ecological Dynamics of Antarctic Krill Populations

Antarctic krill (Euphausia superba) underpins the Southern Ocean food web, sustaining whales, seals, penguins and numerous fish species. Swarming behaviour and vast biomass drive primary productivity via daily vertical migrations that transport carbon and nutrients between surface and depth. Environmental processes—from sea-ice dynamics and ocean currents to temperature and ice cover—shape krill distribution, recruitment and growth. Fluctuations in abundance occur over interannual to decadal scales in response to indices such as sea surface temperature, El Niño and the Southern Annular Mode. Fishing pressure adds complexity, with a spatially concentrated fishery competing with predators for shared stocks. Current research integrates acoustic surveys, satellite data and ecosystem modelling to resolve krill swarm density, biogeochemical cycling and risk to dependent species. These insights are vital for ecosystem-based management and for predicting responses of krill populations to climate change, with implications for carbon sequestration and biodiversity conservation across the Southern Ocean.

Research from Nature Portfolio

Recent studies have highlighted the pivotal role of krill in carbon cycling, demonstrating how their aggregations and vertical migrations mediate nutrient transport and enhance the Southern Ocean carbon sink. Syntheses now argue for the inclusion of both adult and larval krill contributions in management frameworks to safeguard biogeochemical processes alongside stock sustainability. Longitudinal analyses of three decades of observational data reveal that localised harvesting at modest rates can adversely affect penguin breeding success, underscoring mismatches in the spatial and temporal scales of fishery management and predator–prey dynamics. Further work advocates embedding ecological uncertainties—such as variability in krill recruitment and distribution—into ecosystem-based management, recommending adaptive strategies that draw upon real-time data from the fishery itself.

Ecological Dynamics of Antarctic Krill Populations publication trend

The graph below shows the total number of articles in ecological dynamics of antarctic krill populations across all publications each year (not limited to Nature Index journals).

Technical terms

Acoustic survey: A method using sound waves to detect and quantify krill swarms and estimate their density and biomass.

Biogeochemical cycle: The movement and transformation of chemical elements, such as carbon and nutrients, through biological and physical components of the ocean.

Vertical migration: The daily movement of krill between surface waters to feed and deeper waters to avoid predators.

Recruitment: The addition of new juvenile krill into the adult population, influenced by larval survival and growth.

Ecosystem-based management: A holistic approach to resource management that considers species interactions, environmental processes and human activities within an ecosystem.

References

1. Scientific echosounder data provide a predator’s view of Antarctic krill (Euphausia superba). Scientific Data (2023).
2. The importance of Antarctic krill in biogeochemical cycles. Nature Communications (2019).
3. Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013. ICES Journal of Marine Science (2014).
4. Long-term observations from Antarctica demonstrate that mismatched scales of fisheries management and predator-prey interaction lead to erroneous conclusions about precaution. Scientific Reports (2020).
5. Potential Climate Change Effects on the Habitat of Antarctic Krill in the Weddell Quadrant of the Southern Ocean. PLOS ONE (2013).
6. Identifying Risk: Concurrent Overlap of the Antarctic Krill Fishery with Krill-Dependent Predators in the Scotia Sea. PLOS ONE (2017).
7. Successful ecosystem-based management of Antarctic krill should address uncertainties in krill recruitment, behaviour and ecological adaptation. Communications Earth & Environment (2020).
8. Krill, climate, and contrasting future scenarios for Arctic and Antarctic fisheries. ICES Journal of Marine Science (2014).
9. Climatically driven fluctuations in Southern Ocean ecosystems. Proceedings of the Royal Society B (2007).