Getting the measure of krill

Close up of Antarctic krill
The new model developed by Antarctic Division researchers will allow scenarios on the production and dynamics of krill populations to be developed. (Photo: Steve Brookes)

Researchers from the Australian Antarctic Division have used field and aquarium studies to develop an improved model to better estimate krill productivity in the Southern Ocean.

Change in krill productivity (growth and reproduction) under climate change is central to managing and conserving Antarctic marine ecosystem into the future; this is a central question for the Commission for the Conservation of Antarctic Marine Living Resources.

To date, models of krill productivity have not effectively combined the energetics of growth and reproduction with the constraints of the moult cycle.

The new model developed by Antarctic Division researchers Dr Andrew Constable and Dr So Kawaguchi and published this month in ICES Journal of Marine Science, will allow scenarios on the production and dynamics of krill populations to be developed for the future, given the expected changes in the Southern Ocean ecosystems. 

In the past, models of krill production have relied on parameters estimated from sampling of krill in the field, not knowing the direct relationship between the magnitude of environmental factors, including population density, and the rates of growth and reproduction in individual krill.

Combining research at the Antarctic Division’s Tasmanian based krill aquarium and field programs, has enabled many of the parameters required for modelling the biology and production of krill to be estimated directly from experiments.

Dr Kawaguchi said the Division’s krill aquarium, one of only two in the world, is well equipped to then test these hypotheses and provide better estimates of parameters into the future.

Dr Constable said researchers are recommending the new model be incorporated into assessments of catch limits for Antarctic krill.