The behavior of krill is fascinating. Krill either swim forward by using their five pairs of rear paddle-shaped legs or propel themselves quickly backwards using their tails. They feed using a further six pairs of forward legs, each of which is split into two branches and covered with a net-like array of feathery seta. Antarctic krill spawn mainly in the summer months and adult females are able to lay between two and three thousand eggs twice a year. As the larva grow they gradually rise towards the surface, taking two to three years to mature.
Krill live at least two and possibly up to five years.
As adults, they gather in huge swarms near the surface of the ocean, which is one of the reasons why they can be easily fished. There is a marked seasonal cycle of vertical movement in the sea in krill as part of their growth pattern. In winter they graze on algae growing on the underside of the pack-ice. The krill also have a daily cycle. At night they rise to the surface but sink again during the daylight hours.