Krill Sex
Preliminary research at the Australian Antarctic Division's krill aquarium has shown that the annual cycle of krill maturation and reproduction can be altered by a period of darkness immediately after spawning.
'We've been able to reset the animals' internal clocks, so that they become sexually mature three months earlier than if they were exposed to a natural Antarctic light cycle,' principal researcher, Dr So Kawaguchi says.
The research promises to allow scientists to control when different groups of krill spawn, so that they have access to all phases of the life cycle (larvae, juveniles, sub-adults and adults) all year round. It will also spread the effort of collecting millions of krill eggs for the breeding program, over the year, rather than all at once.
In Antarctica, krill experience four months of darkness over winter, between June and September. During this time they actually shrink in size and lose their mature reproductive characteristics – a process known as 'regression'. As spring approaches and the day length and food supply increases, they begin to grow and become sexually mature again, before mating begins in December and continues until about February.
Research at the Antarctic Division in the late 1980s showed that krill would steadily progress through their reproductive cycle regardless of whether they were exposed to constant darkness, constant light, or a natural Antarctic light cycle.
