External parasite infestation depends on moult-frequency and age in Antarctic krill (Euphausia superba)

Tarling, Geraint A. ORCID:; Cuzin-Roudy, J.. 2008 External parasite infestation depends on moult-frequency and age in Antarctic krill (Euphausia superba). Polar Biology, 31 (2). 121-130.

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Levels of infestation by the suctorian Ephelota sp. were determined in Antarctic krill taken in the north-eastern region of the Scotia sea, close to the island of South Georgia. Individuals caught in summer between 2002 and 2004 were measured for body length, eye diameter, moult stage, sex, sexual maturity and number of suctorian parasites. All krill samples were found to contain at least two modal size-classes and the complete range of maturity- and moult stages. Sample analysis for the different characters identified moult stage as an important determinant of infestation by Ephelota sp., with 66% of those about to moult (pre-moult individuals) being infested compared with 0% of post-moult individuals. Multiple Correspondence Analysis also identified a strong link between age and degree of suctorian infestation with large-eyed (and hence old) males having very high numbers of suctorian bodies. Moulting is costly in terms of energy and vulnerability, but it is believed that krill moult at relatively high rates throughout their life to facilitate growth and "shrinkage". Here, we demonstrate that the control of external parasitism is also a major advantage of moulting at high frequency. The capacity of krill to maintain a high moult rate decreases with age, leading to older krill enduring higher parasitic loads.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > DISCOVERY 2010 - Integrating Southern Ocean Ecosystems into the Earth System
ISSN: 0722-4060
Additional Keywords: population structure; body length; eye diameter; moult cycle; sexual development; age; suctorian; Ephelota sp; parasite load; South Georgia; Scotia sea
NORA Subject Terms: Marine Sciences
Biology and Microbiology
Ecology and Environment
Date made live: 20 Jan 2011 13:56 +0 (UTC)

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