New Clues on Formation of Krill Swarms
15.10.2009 - Water & Oceans, Flora & Fauna, Human Dimension, Other, Antarctic
Krill swarm formation, a subject previously unstudied by science, hasbeen investigated recently by a team of scientists from the BritishAntarctic Survey. The report, which was published in the journal DeepSea Research I, shows the team discovered two types of swarm.
The research, which was conducted in the area between South Georgia Island and the Antarctic Peninsula, shows how krill swarms seem to discriminate on the basis of maturity: small swarms consist of adult krill, while the bigger swarms are made up of juvenile swarms. While the small swarms are mostly around 50 meters long and only four meters deep, the big ones can stretch for several kilometers and are about 30 meters deep.
However the difference between both types of swarm is not restricted by size or maturity. The report shows krill density is ten times as high in the bigger swarms as it is in the smaller swarms. The higher density in the bigger swarms would be justified by the need for protection for juvenile krill and provide a substantial gain in energy, allowing the krill to grow faster. The less dense adult swarms would benefit from less competition than juvenile swarms.
However juvenile krill swarming together makes them susceptible to overfishing as fishing fleets can locate them easily and catch them, putting severe stress on the food chain by depleting an animal at the bottom.
