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Metabolic scope, swimming performance and the effects of hypoxia in the mulloway, Argyrosomus japonicus (Pisces: Sciaenidae)

Citation

Fitzgibbon, QP and Strawbridge, A and Seymour, RS, Metabolic scope, swimming performance and the effects of hypoxia in the mulloway, Argyrosomus japonicus (Pisces: Sciaenidae), Aquaculture, 270, (1-4) pp. 358-368. ISSN 0044-8486 (2007) [Refereed Article]

Copyright Statement

Copyright 2007 Elsevier B.V.

DOI: doi:10.1016/j.aquaculture.2007.04.038

Abstract

The culture of the mulloway (Argyrosomus japonicus), like many other Sciaenidae fishes, is rapidly growing. However there is no information on their metabolic physiology. In this study, the effects of various hypoxia levels on the swimming performance and metabolic scope of juvenile mulloway (0.34 0.01 kg, mean SE, n = 30) was investigated (water temperature = 22 C). In normoxic conditions (dissolved oxygen = 6.85 mg l−1), mulloway oxygen consumption rate (Mo2) increased exponentially with swimming speed to a maximum velocity (Ucrit) of 1.7 < 0.1 body lengths s−1 (BL s−1) (n = 6). Mulloway standard metabolic rate (SMR) was typical for non-tuna fishes (73 8 mg kg−1 h−1) and they had a moderate scope for aerobic metabolism (5 times the SMR). Mulloway minimum gross cost of transport (GCOTmin, 0.14 0.01 mg kg−1 m−1) and optimum swimming velocity (Uopt, 1.3 0.2 BL s−1) were comparable to many other body and caudal fin swimming fish species. Energy expenditure was minimum when swimming between 0.3 and 0.5 BL s−1. The critical dissolved oxygen level was 1.80 mg l−1 for mulloway swimming at 0.9 BL s−1. This reveals that mulloway are well adapted to hypoxia, which is probably adaptive from their natural early life history within estuaries. In all levels of hypoxia (75% saturation = 5.23, 50% = 3.64, and 25% = 1 .86 mg l−1), Mo2 increased linearly with swimming speed and active metabolic rate (AMR) was reduced (218 17, 202 14 and 175 10 mg kg−1 h−1 for 75%, 50% and 25% saturation respectively). However, Ucrit was only reduced at 50% and 25% saturation (1.4 < 0.1 and 1.4 < 0.1 BL s−1 respectively). This demonstrates that although the metabolic capacity of mulloway is reduced in mild hypoxia (75% saturation) they are able to compensate to maintain swimming performance. GCOTmin (0.09 0.01 mg kg−1 m−1) and Uopt (0.8 0.1 BL s−1) were significantly reduced at 25% dissolved oxygen saturation. As mulloway metabolic scope was significantly reduced at all hypoxia levels, it suggests that even mild hypoxia may reduce growth productivity.

Item Details

Item Type:Refereed Article
Keywords:mulloway, hypoxia, Argyrosomus japonicus, sciaenidae, metabolic scope, swimming performance, standard metabolic rate, active metabolic rate
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Aquaculture
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Aquaculture
Objective Field:Fisheries - Aquaculture not elsewhere classified
Author:Fitzgibbon, QP (Dr Quinn Fitzgibbon)
ID Code:94751
Year Published:2007
Web of Science® Times Cited:29
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2014-09-16
Last Modified:2014-10-06
Downloads:0

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