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 Adelie 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 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.
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.
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.
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.
What You Can Do? Krill’s importance to the Antarctic ecosystem makes it clear that they need to be protected – without krill, many beloved animals such as whales, seals and penguins would not be able to survive! How can you protect krill? You can avoid purchasing products made from Antarctic krill until it is clear that stringent management and research requirements have been put in place. Additionally, avoid eating farmed salmon, which is often fed using meal made from krill. This process is inefficient (it takes several pounds of krill to produce one pound of salmon) and many salmon farms have serious pollution problems.
Recently, it has been reported that the Antarctic krill harvest is environmentally-friendly because a portion of the catch has been certified as “sustainable” by the Marine Stewardship Council. The MSC has certified this fishery over the objections of ASOC and in the face of inadequate scientific evidence. ASOC urges consumers not to purchase products made from krill, regardless of the presence of the Marine Stewardship Council (MSC) “sustainable” label.
Article from: Antarctic and Southern Ocean Coalition