A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice habitats are, however, vital for larval krill when water column productivity is limited by light, by providing structures that offer protection from predators and to collect organic material released from the ice. The larvae feed on this sparse ice-associated food during the day. After sunset, they migrate into the water below the ice (upper 20 m) and drift away from the ice areas where they have previously fed. Model analyses indicate that this behaviour increases both food uptake in a patchy food environment and the likelihood of overwinter transport to areas where feeding conditions are more favourable in spring.

Item Type:	Refereed Article
Keywords:	krill, ecosystem based management, ecosystem modelling, life history, habitat structural complexity, sea ice, under-ice habitat
Research Division:	Environmental Sciences
Research Group:	Environmental management
Research Field:	Wildlife and habitat management
Objective Division:	Environmental Management
Objective Group:	Coastal and estuarine systems and management
Objective Field:	Assessment and management of coastal and estuarine ecosystems
UTAS Author:	Meiners, KM (Dr Klaus Meiners)
UTAS Author:	Melbourne-Thomas, J (Dr Jessica Melbourne-Thomas)
UTAS Author:	Kawaguchi, S (Dr So Kawaguchi)
UTAS Author:	Sumner, M (Mr Michael Sumner)
UTAS Author:	Trebilco, R (Dr Rowan Trebilco)
ID Code:	122426
Year Published:	2017
Web of Science® Times Cited:	66
Deposited By:	CRC-Antarctic Climate & Ecosystems
Deposited On:	2017-11-14
Last Modified:	2018-04-20
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