. These are successful techniques, apparently, since the total biomass, or weight, of Antarctic krill — which is estimated to be between 100 and 800 million tons — may be the largest of any multi-cellular animal on the planet
These small, shrimp-like creatures represent the very cornerstone of the Antarctic ecosystem. This vast resource has long attracted the gaze of the commercial fishing industry, which began krill fishing in the early-1970s. Krill are presently harvested for human consumption, fish feed, and sport fishing bait by vessels from Japan, South Korea, Poland, and the Ukraine, yet the growth of the krill fishing industry has been relatively slow since krill are notoriously difficult to process: their powerful digestive enzymes spoil the catch soon after it is caught, and their shells are cumbersome to remove. Nevertheless, there are concerns about the potential for over fishing in the near future due to the growing demands of aquaculture. Krill are often used as fish feed and salmon farmers in particular find them attractive because they contain astaxanthin, a carotenoid that turns salmon flesh pink. The burgeoning biotechnology industry is also interested in krill since drug companies claim they contain substances that can be used to treat heart disease, premenstrual tension, and skin cancer. Meanwhile, as ocean temperatures rise and the Antarctic sea ice melts, research suggests that krill populations may decrease as the krill are out-competed by salps, barrel-shaped filter feeders that likewise eat phytoplankton and thrive in warmer water temperatures.
In the end, there is still a lot to learn about krill in order to accurately assess their abundance, and best determine how to preserve their population. Scientists, for instance, don’t yet know precisely how long they live or how they survive the long, dark winters. It is suspected that the krill actually shrink, using up the material of their own bodies until the return of the light, and photosynthesizing plants. Until the answers to such questions are found, however, it is difficult to gauge the potential impact of either commercial fishing or global warming on the krill population that is so vital for the sustenance of the entire Antarctic.
(Photo: MAR-ECO/Øystein Paulsen)