Ecologist
KRILLBASE
KRILLBASE: Circumpolar data on Antarctic krill and salps
- Start date:
- 1 January, 1998
What KRILLBASE does
KRILLBASE is a data rescue and compilation project. It focuses on two key Southern Ocean zooplankton species: Antarctic adult krill and salps.

In 2016, KRILLBASE released a database of 12,880 net samples. These were collected between 1926 and 2016 by scientists from ten countries. Each record includes krill or salp density per square metre of sea surface. It also records environmental conditions and sampling details.
KRILLBASE has also produced two other databases of the length of individual krill in net samples and the abundance of larval krill.
Why this matters
Antarctic krill are shrimp-like crustaceans in the Southern Ocean. Their numbers are vast—about 780 trillion individuals, not counting eggs and larvae. They are found throughout the region and at all depths.

Krill swarm captured in a net-cam during a marine cruise in Antarctica
Krill are prey for many animals, from brittlestars to great whales. They also graze on phytoplankton, shaping food webs and biogeochemical cycles of carbon, nitrogen, and other essential elements.
Krill are harvested by fisheries. Careful management is needed to prevent ecosystem disruption. Data on krill distribution and population change support sustainable fisheries, the design of marine protected areas, and conservation policy.
Salps are jelly-like filter feeders. They are similar in size to krill. Salps switch between living alone and forming long chains. Sometimes these chains form dense blooms.
Salps are also key members of the ecosystem. They often thrive when krill struggle and may increase with climate change. Studying salps helps reveal broader changes that affect krill.
The KRILLBASE datasets are a major resource for studying these topics because they provide a detailed picture of the distribution and abundance of krill and slaps in the Southern Ocean.
A brief history of KRILLBASE
In the 1990s, several countries began monitoring programmes in the Southern Ocean. They sampled the same areas each year to track ecological change.
At the same time, KRILLBASE founders saw the value of combining these new data with older records. Much of the older material was scattered in archives, faded logbooks, old disks, or inaccessible databases.
Rescuing and compiling this information became a central goal.
KRILLBASE has also produced research papers that improve understanding of krill and their ecosystems.
In 2016, with support from WWF, KRILLBASE released the first public circumpolar dataset on krill and salp density. These data can be downloaded from the “Data” tab on the project website.
Who is involved
KRILLBASE brings together an international network of researchers and institutions. The project now works with scientists from the US, UK, Germany, Ukraine, Australia, South Africa, Japan, Poland, Spain, Norway, and Chile. Collaboration is key to rescuing historical data and adding new data.
To improve the availability of information on two of the Southern Ocean’s most important zooplankton taxa: Antarctic krill (Euphausia superba) and salps (Family Salpidae).
Project contributors
KRILLBASE is an international project involving collaborators from eleven countries and compiling data collected by research programmes in the USA, UK, Germany, former Soviet Union, Australia, South Africa, Japan, Poland, Spain and Norway. It was founded by Angus Atkinson, Evgeny Pakhomov and Volker Siegel in the late 1990s. The full list of contributors is:
| A. Atkinson | Plymouth Marine Laboratory | UK |
| R. Anadon | University of Oviedo | Spain |
| S. Chiba | Japan Agency for Marine-Earth Science and Technology | Japan |
| K.L. Daly | University of South Florida | USA |
| R. Downie | WWF | UK |
| Fretwell P | British Antarctic Survey | UK |
| L Gerrish | British Antarctic Survey | UK |
| G.W. Hosie | Sir Alister Hardy Foundation for Ocean Sciences | UK |
| S.L. Hill | British Antarctic Survey | UK |
| M.J. Jessopp | University College Cork | Ireland |
| S. Kawaguchi | Australian Antarctic Division | Australia |
| B.A. Krafft | Institute of Marine Research | Norway |
| V. Loeb | Moss Landing Marine Laboratories | USA |
| J. Nishikawa | Tokai University | Japan |
| E. A. Pakhomov | University of British Columbia | Canada |
| H.J. Peat | British Antarctic Survey | UK |
| C.S Reiss | NOAA Fisheries | USA |
| R.M. Ross | University of California at Santa Barbara | USA |
| L.B. Quetin | University of California at Santa Barbara | USA |
| K. Schmidt | Sir Alister Hardy Foundation for Ocean Sciences | UK |
| D.K Steinberg | Virginia Institute of Marine Science | USA |
| V. Siegel | Thünen Institute of Sea Fisheries | Germany |
| R.C. Subramaniam | University of Tasmania | Australia |
| G.A. Tarling | British Antarctic Survey | UK |
| P. Ward | British Antarctic Survey (retired) | UK |
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Krill swarms responsible for ‘hidden’ carbon storage
Read more of: Krill swarms responsible for ‘hidden’ carbon storageLarge krill swarms in the Southern Ocean could help remove additional carbon from the atmosphere, in a way that is currently ‘hidden’ in global models. The new study is published […]
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Antarctic krill population contracts southward as polar oceans warm
Read more of: Antarctic krill population contracts southward as polar oceans warmThe population of Antarctic krill, the favourite food of many whales, penguins, fish and seals, shifted southward during a recent period of warming in their key habitat, new research shows. […]
The publication of the KRILLBASE data was funded by WWF.
The project aims to compile a range of data on krill and salps in the Southern Ocean. The main data product is the database of densities (number under 1m2 of sea surface) spanning 1926 to 2016.
These data were collected using a variety of net sampling methods. Krill densities are available both as observed densities and as standardised densities (standardised to a single net sampling method) to allow comparison of data collected using different methods.
It is important to be aware of the caveats associated with these data. The following paper describes the dataset and the caveats and limitations on its use has been submitted to a journal:
Atkinson A, Hill SL, Pakhomov E, Siegel V, Anadon R, Chiba S, Daly KL, Downie R, Fielding S, Fretwell P, Gerrish L, Hosie GW, Jessopp MJ, Kawaguchi S, Krafft BA, Loeb V, Nishikawa J, Peat HJ, Reiss CS, Ross RM, Langdon B. Quetin, Schmidt K, Steinberg DK, Subramaniam RC, Tarling GA, Ward P (2017) KRILLBASE: a circumpolar database of Antarctic krill and salp numerical densities, 1926–2016. Earth Syst. Sci. Data, 9: 193-2107 [Link]
The main caveats are that:
- Sampling method varies between areas and between years. Consider the potential influence of sampling variability on results.
- Some nets do not sample the upper layers of the water column. It might be appropriate to exclude such data.
- The accuracy of date and time of day information varies between records. This can affect the standardised results.
- Nets are likely to under-sample mobile animals such as krill. The data therefore provide a relative index of krill density.
The DOI for dataset is doi.org/brg8 (long form: doi:10.5285/8b00a915-94e3-4a04-a903-dd4956346439).
These data have been collected by research programmes in ten countries and made available by a large group of project participants. These participants have also contributed to the submitted data paper which, when published, will form a citable description of the data.
Follow this link to the data.
The paper by Atkinson et al (2017) should be cited when analyses of these data are published.
