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Plasticity in vertical behaviour of migrating juvenile southern bluefin tuna (Thunnus maccoyii) in relation to oceanography of the south Indian Ocean

Citation

Bestley, S and Gunn, JS and Hindell, MA, Plasticity in vertical behaviour of migrating juvenile southern bluefin tuna (Thunnus maccoyii) in relation to oceanography of the south Indian Ocean, Fisheries Oceanography , 18, (4) pp. 237-254. ISSN 1054-6006 (2009) [Refereed Article]

DOI: doi:10.1111/j.1365-2419.2009.00509.x

Abstract

Electronic tagging provides unprecedented information on the habitat use and behaviour of highly migratory marine predators, but few analyses have developed quantitative links between animal behaviour and their oceanographic context. In this paper we use archival tag data from juvenile southern bluefin tuna (Thunnus maccoyii, SBT) to (i) develop a novel approach characterising the oceanographic habitats used throughout an annual migration cycle on the basis of water column structure (i.e., temperature-at-depth data from tags), and (ii) model how the vertical behaviour of SBT altered in relation to habitat type and other factors. Using this approach, we identified eight habitat types occupied by juvenile SBT between the southern margin of the subtropical gyre and the northern edge of the Subantarctic Front in the south Indian Ocean. Although a high degree of variability was evident both within and between fish, mixed-effect models identified consistent behavioural responses to habitat, lunar phase, migration status and diel period. Our results indicate SBT do not act to maintain preferred depth or temperature ranges, but rather show highly plastic behaviours in response to changes in their environment. This plasticity is discussed in terms of the potential proximate causes (physiological, ecological) and with reference to the challenges posed for habitat-based standardisation of fishery data used in stock assessments. © 2009 Blackwell Publishing Ltd.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and Estuarine Ecology (incl. Marine Ichthyology)
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Wild Caught
Objective Field:Wild Caught Tuna
Author:Bestley, S (Dr Sophie Bestley)
Author:Hindell, MA (Professor Mark Hindell)
ID Code:57412
Year Published:2009
Web of Science® Times Cited:21
Deposited By:Zoology
Deposited On:2009-07-16
Last Modified:2010-04-27
Downloads:0

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