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The influence of freshwater inflows on spawning success and early growth of an estuarine resident fish species, Acanthopagrus butcheri


Sakabe, R and Lyle, JM and Crawford, C, The influence of freshwater inflows on spawning success and early growth of an estuarine resident fish species, Acanthopagrus butcheri, Journal of Fish Biology, 78, (5) pp. 1529-1544. ISSN 0022-1112 (2011) [Refereed Article]

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DOI: doi:10.1111/j.1095-8649.2011.02959.x


The influence of freshwater inflows and salinity on spawning success of black bream Acanthopagrus butcheri (Sparidae) was investigated over 2 years in a small estuary on the east coast of Tasmania,Australia. The individual spawning seasons experienced quite different freshwater inflows; 2004–2005 was characterized by low flows throughout the season whereas during 2005–2006 there were three relatively large discharge events in the first part of the season. Macroscopic gonad staging of adults was used to define the spawning season and daily increment analysis of otoliths from recently settled recruits was used to backcalculate spawning dates. Gonad staging indicated that adults were in spawning condition over a 3 to 4 month period during spring and summer. The timing and duration of successful spawning, however, differed markedly between years and was linked to the timing of freshwater inflows and salinity conditions, with successful spawning occurring during periods of low freshwater discharge and when salinities in the upper estuary were above c. 15. Growth rates of the recently settled recruits did not differ between years, nor did the timing of spawning within the season influence growth rates. While the latter finding was unexpected,especially given within season temperature variability, these results imply that by the onset of winter earlier spawned fish would be larger than later spawned individuals, potentially conferring advantages for survival and competition for food. Climate change predictions for eastern Tasmania indicate a decrease in river flows in spring and an increase during summer, potentially increasing environmental variability between and within years, with implications for spawning success and subsequent recruitment.

Item Details

Item Type:Refereed Article
Keywords:daily increment analysis; Little Swanport Estuary; reproductive cycle; salinity; spawning
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Aquaculture and fisheries stock assessment
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - wild caught
Objective Field:Wild caught fin fish (excl. tuna)
UTAS Author:Sakabe, R (Mr Ryuji Sakabe)
UTAS Author:Lyle, JM (Associate Professor Jeremy Lyle)
UTAS Author:Crawford, C (Dr Christine Crawford)
ID Code:70529
Year Published:2011
Web of Science® Times Cited:14
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2011-06-27
Last Modified:2014-12-18
Downloads:3 View Download Statistics

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