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Influence of individual state on swimming capacity and behaviour of Antarctic krill Euphausia superba

Johnson, Magnus L.; Tarling, Geraint A.

Authors

Geraint A. Tarling



Abstract

Swarms of Antarctic krill are frequently biased towards certain body sizes, sexes, maturities and physiological states. However, the mechanisms causing such biases remain unclear, with some speculating on differential responses to chemical or visual cues. This study examines the influence of individual state on swimming behaviour and performance, which, in turn, may cause biases in swarm composition. The frequency and strength of pleopod beats as well as the overall swimming capacity of Antarctic krill Euphausia superba were measured using a tethering technique. Individual state was considered in terms of body size, sex, maturity, moult stage and stomach fullness. Significant differences in the rate and strength of pleopod strokes as well as in the overall swimming capacity were found between individuals in different states. Body size had one of the strongest influences, with beat rate decreasing and beat strength increasing with increasing size. The sex and maturity of an individual altered this pattern, with adult females having faster but weaker pleopod beats than males of equivalent size. The difference in swimming style of females may impose a different lifestyle to that of males. Moult stage also had a significant influence on swimming, with moulting/post-moult individuals having significantly lower swimming capacities, making them unlikely to keep pace with intermoult counterparts. Both the rate and the strength of the pleopod beat were significantly lower in satiated compared to unsatiated individuals, which may contribute to the dispersion of swarms during feeding.

Citation

Johnson, M. L., & Tarling, G. A. (2008). Influence of individual state on swimming capacity and behaviour of Antarctic krill Euphausia superba. Marine ecology progress series, 366, 99-110. https://doi.org/10.3354/meps07533

Journal Article Type Article
Acceptance Date Apr 21, 2008
Publication Date Aug 29, 2008
Deposit Date Nov 13, 2014
Journal Marine Ecology-Progress Series
Print ISSN 0171-8630
Publisher Inter Research
Peer Reviewed Peer Reviewed
Volume 366
Pages 99-110
DOI https://doi.org/10.3354/meps07533
Keywords Sex-dependent; Moult; Maturity; Swarm; Satiation; Pleopods; Antarctic; Southern Ocean
Public URL https://hull-repository.worktribe.com/output/461110
Publisher URL https://www.int-res.com/abstracts/meps/v366/p99-110/
Contract Date Nov 13, 2014