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Integrated approach to determining stock structure: implications for fisheries management of sardine, Sardinops sagax, in Australian waters

Citation

Izzo, C and Ward, TM and Ivey, AR and Suthers, IM and Stewart, J and Sexton, SC and Gillanders, BM, Integrated approach to determining stock structure: implications for fisheries management of sardine, Sardinops sagax, in Australian waters, Reviews in Fish Biology and Fisheries, 27 pp. 267-284. ISSN 0960-3166 (2017) [Refereed Article]


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DOI: doi:10.1007/s11160-017-9468-z

Abstract

The stock structure of small pelagic fishes is difficult to determine due to their patchy distribution and complex movement patterns. We integrate genetic, morphological, otolith, growth, reproductive and fishery data collected over 60 years using a Stock Differentiation Index (SDI). The absence of strong separation (SDI > 0.66) of most adjacent sub-groups supports the hypothesis that sardine (Sardinops sagax) in Australian waters is a meta-population, but with effective isolation of at least four stocks: south western coast (off Western Australia); Great Australian Bight and Spencer Gulf; Bass Strait and Port Phillip Bay (off Victoria and Tasmania); and eastern Australia. There is also evidence for sub-division of the stocks off Western Australia and the east coast. We examine age-related and inter-annual patterns of stock structure off South Australia and the east coast through integrated analysis of otolith chemistry and shape data. For the east coast, there were significant differences between northern and southern sub-groups for all three age cohorts examined. Fish were correctly classified to sampling region with a high degree of success (>80%), supporting the sub-division of the east coast stock suggested by the SDI. For South Australia, there were significant differences among two sub-groups for most cohorts examined across two sampling years. However, spatial discriminatory power was poor, with allocation success ranging from 48 to 64%. Results suggest that movements between the two South Australian sub-groups may vary among years, which is consistent with inconclusive SDI (0.5). Integrating historical data using a SDI is suitable for identifying fishery management units. Integrated analysis of otoliths from archival collections is useful for examining temporal variability in stock structure, which is also important for fisheries management. Our findings are relevant to fisheries where sustainability risks are increased by management arrangements based on assumptions that stock structure is absent or stable.

Item Details

Item Type:Refereed Article
Keywords:sardine, stock structure, stock differentiation index, otolith chemistry
Research Division:Agricultural, Veterinary and Food 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:Ward, TM (Associate Professor Timothy Ward)
ID Code:147463
Year Published:2017
Web of Science® Times Cited:16
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2021-11-02
Last Modified:2021-11-03
Downloads:0

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