Krill Conservation

KilsheadkilsThe head of Antarctic krill. Photographed by Uwe Kils.ASOC is a key partner in the Antarctic Krill Conservation Project, whose goal is to protect the base of the Antarctic marine ecosystem – krill.

Most marine species in the Southern Ocean – including whales, seals, penguins, albatrosses, petrels, squid and many others – feed on this small shrimp-like organism.

While the krill fishery has historically grown slowly, new technologies now allow catches to be processed more quickly, stimulating more interest in krill fishing from industry.

The potential market for krill products is also growing. Krill are not often used for human food, but are used to make feed for farmed fish, nutritional supplements, and other products.

The demand for these products continues to increase, and ASOC firmly believes that the Antarctic krill fishing industry must be strictly supervised by the Commission on the Conservation of Antarctic Marine Living Resources (CCAMLR) to ensure that the Antarctic marine ecosystem remains healthy.

2010 marked the first time that part of the krill fishery had to be closed due to the catch limit for that area being reached, even though the whole krill fishery was not closed. This event is an example of the urgent need to adapt additional management regulations - the fishery has a natural tendency to concentrate in whichever areas have the largest populations of krill in a given year.

The problem with this is that krill predators in these areas cannot always move to another area to avoid competing with fishing boats. Penguins in particular cannot travel too far from their nests in search of food when raising chicks. While we know that localized depletions of krill can have an impact on predators, we do not have good information on the needs of predators in the areas typically used by the fishery.

Without this information, CCAMLR cannot truly know if the krill harvest is going to affect krill predators. There is also considerable uncertainty about the status of the krill population.

Antarctic krill (Euphausia superba). Photographed by Uwe Kils

Krill Facts

Krill are tiny creatures - measuring about 2.5 inches long and weighing about two grams - but they are the primary food for a wide range of species, including the world's largest animal, the blue whale. Krill are found all over the world and are important components of many ecosystems, but Antarctic krill occupy an extremely important place in the Antarctic food web. They are thought to have the largest population of any species on Earth.

Blue whales can eat up to 4 tons of krill per day, and other baleen whales can also consume thousands of pounds of krill per day. Krill themselves feed on phytoplankton and often aggregate in swarms of millions or even billions. Krill also like to feed on the algae that accumulates under sea ice. Part of the reason that Antarctic krill are so numerous is that the waters of the Southern Ocean around Antarctica are very rich sources of phytoplankton and algae that grows on the underside of sea ice.

However, sea ice cover is not constant around Antarctica, leading to fluctuations in krill populations. The West Antarctic Peninsula, which is one of the most rapidly warming areas in the world, has experienced a measurable loss of sea ice. over the past few decades.

Krill populations in the area, as well as populations of krill-dependent Adélie penguins, are declining. There has also been a long term decline in the total population of krill since the 1970s, for reasons that have not been conclusively determined.

It is likely that the decline is related to the decrease in sea ice, but it may be partially due to the impact of previous whaling activity. This is known as the "krill paradox," because most scientists expected that the removal of large numbers of whales would cause an explosion in the numbers of krill and subsequently other krill predators, but this has not been the case.

Amazing as it may sound, the most numerous species on Earth may currently be a fraction of its former size. The last biomass estimate of krill was performed in 2000, so it is unknown if current catch limits (based on this 2000 estimate) are still accurate.

Krill are recognized as key species in many ecosystems all over the world. The United States preemptively banned krill fishing off the Pacific Coast - before there was even any commercial fishery in place - to preserve the ecosystem and protect other commercially valuable species that are dependent on krill.

1024px-KrillicekilsAntarctic krill scraping ice algae in Antarctica. Photographed by ATOLL laboratory.

Key Actions Needed to Protect Krill

ASOC believes that several important steps must be taken immediately to ensure the long-term health of the krill population. These include:

Undertake new krill biomass surveys:As mentioned above, the current biomass estimate is based on data from the year 2000 and is likely to be inaccurate. Krill are very sensitive to environmental changes, and the growing threat of climate change necessitates up-to-date information on the status of the Antarctic krill population. Krill fishing vessels should be encouraged to conduct small-scale acoustic surveys as part of their fishing operations.

Strengthen and fund programs to monitor the Antarctic ecosystem:CCAMLR has adopted a feedback approach to krill fisheries management which requires management measures to be continuously adjusted as relevant information becomes available on the interactions between krill fishing and krill predators. However, this feedback management cannot be properly implemented without an effective CCAMLR Ecosystem Monitoring Program (CEMP). Unfortunately, data submitted to CEMP has been decreasing in recent years. For this reason, in 2009, CCAMLR's Scientific Committee advised that a review of CEMP, including the requirements for its monitoring reference sites, was an urgent priority. Fishing nations must help fund these on-going research and monitoring needs. The issues that need more research and data gathering are as follows: krill and krill predator populations, their distribution and seasonal and inter-annual variability, as well as predator-prey relationships and the effects of climate change.

KrilldistributionKrill distribution on a NASA SeaWIFS image – the main concentrations are in the Scotia Sea at the Antarctic Peninsula.

Revise the spatial distribution of the krill catch: There is currently a "trigger level" catch limit for the fishery that is lower than the total allowable catch of 3.47 tons. Once the trigger level is reached, it is mandatory that any other catches up to the total catch limit be carefully distributed over the fishing area. Although current catches have not reached the trigger limit, they are growing each year. Risk assessments indicate that the that the trigger level is not sufficiently precautionary, due to the excessive fishing concentration in coastal areas. The conditions under which the trigger level was established in 1991 have changed, especially the impacts from climate change which have increased significantly. The krill catch should be distributed spatially across the fishing area, based on scientific advice about krill predator needs, as soon as possible.

The Antarctic Krill Conservation Project (AKCP) website provides many important documents, photos and other information about the campaign.