Stable isotopes of δ¹⁸O and δ¹³C in sagittal otolith carbonates were used to determine the stock structure of the polynemid Eleutheronema tetradactylum (Shaw) across tropical northern Australia, where this species is an important component of inshore commercial and recreational fisheries. Stable isotopes from the sagittal otolith carbonate of 470 fish from 11 discrete locations across western, northern and eastern Australia were sampled between 2007 and 2009. Analysis of these stable isotopes revealed different location-specific signatures, indicating strong population subdivision. The significant differences in the isotopic signatures of E. tetradactylum demonstrated that there is unlikely to be substantial movement of fish between these locations. The spatial separation of these populations indicates a complex fine spatial scale stock structure across northern Australia, with at least 11 stocks or management units present. The population subdivision of E. tetradactylum was evident along expansive stretches of open beach systems and within coastal embayments with no physical barriers such as headlands. These results indicate that optimal fisheries management will require a review of the current spatial arrangements, particularly the potential for localised depletion of stocks on small spatial scales.

Item Type:	Refereed Article
Keywords:	connectivity, fisheries management, Polynemidae, population subdivision, stable isotope chemistry
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Fisheries Sciences
Research Field:	Fisheries Management
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - Wild Caught
Objective Field:	Wild Caught Fin Fish (excl. Tuna)
UTAS Author:	Moore, BR (Dr Bradley Moore)
ID Code:	121423
Year Published:	2011
Web of Science® Times Cited:	14
Deposited By:	Sustainable Marine Research Collaboration
Deposited On:	2017-09-28
Last Modified:	2017-11-02
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