Antarctic krill's eyes hold key to age

How do you tell how old an Antarctic krill is? Count the rings around their eyes.

In a scientific first, researchers have shown they can determine the age of the creatures by counting the bands around their eyes, similar to the way tree trunk rings are counted.

Findings published on Thursday in scientific journal Plos One show Antarctic krill annually grow bands around their eyestalks, directly correlating to their age.

Until now scientists had difficulty assessing the age of krill due to their lack bone structure, shell or scales and could not rely on their size.

But now they will be able to age preserved krill from as far back as the early 1900s.

"Better understanding how long they live will help us more accurately predict the potential impacts of climate change on krill," Australian Antarctic Division krill biologist Dr So Kawaguchi said.