Krill have often been called the 'key' animals of the Antarctic region. The are the world's most abundant crustacean and they form the staple diet of many animals including seals, whales, fish, squid, penguins and other seabirds.
How much krill is in the Southern Ocean, and how the population fluctuates, are therefore major questions to address in considering the protection of the Antarctic environment, particularly since krill have been fished commercially for 25 years. During this period, the waters off the Australian Antarctic Territory have been regularly fished, with the annual krill catch reaching a maximum of 155,000 tonnes in 1981. Krill fishing in the late 1990s, however, has been between 80,000 and 100,000 tonnes per year.
Scientists here have developed sophisticated echo sounder technology and software to provide the best estimates so far of krill abundance and distribution in the Indian Ocean sector. This information has been used by the international body that regulates the fisheries of the region - the Commission for the Conservation of Antarctic Marine Living Resources - to set conservative, or precautionary, fishing limits which allow for the needs of all the other animals in the ecosystem.
Of course, managing the krill fishery needs more than an estimate of how much krill is out there. In studies on board Aurora Australis and at the Antarctic Division's unique cold-water krill research aquarium at Kingston, scientists are examining aspects of the biology of krill that will contribute to the sustainable management of the krill resource. Such studies focus on krill growth, ageing and production, all important inputs to the mathematical models used to manage the fishery. The combination of survey work, experimental research and theoretical analysis provides a comprehensive and world-leading approach to the study of krill and is an important contribution to the goal of protecting the Antarctic environment.