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Effects of dissolved organic carbon and hardness in freshwater used to treat amoebic gill disease


Green, TJ and Powell, MD and Harris, JO and Butler, R, Effects of dissolved organic carbon and hardness in freshwater used to treat amoebic gill disease, Aquaculture Research, 36, (4) pp. 398-404. ISSN 1355-557X (2005) [Refereed Article]

DOI: doi:10.1111/j.1365-2109.2005.01221.x


Amoebic gill disease (AGD) is a significant disease of Atlantic salmon farmed in South East Tasmania. The commercial treatment for the disease is a freshwater bath for up to 4 h. Previous studies have shown that the chemical composition of the freshwater, in particular total water hardness, affects the efficacy of the treatment. The aim of this study was to determine if other water chemistry parameters, such as dissolved organic carbon (DOC), interact with total water hardness to affect treatment success. Firstly, the relative survival of isolated gill amoebae incubated for up to 3 h with hard or soft water (346.0 and 34.6 mg L -1 CaCO 3 respectively) with low or high concentrations of humic or tannic acid (5 and 50 mgL -1 respectively) was determined. Secondly, fish with AGD were bathed for 2.5 h in hard or soft water (249.3 and 35.3 mg L -1 CaCO 3) containing either 5 or 20 mg L -1 humic acid. The number of viable amoebae surviving on the gills and number of gill lesions were determined. It was found that the concentration of DOC used in this study that represents the levels commonly found around SE Tasmania is unlikely to have any commercial significance in the reduction in amoebae on the gills of Atlantic salmon. However, this study provided further support that freshwater selected for bathing AGD-affected salmonids should be chosen primarily on its total water hardness. © 2005 Blackwell Publishing Ltd.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food 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
UTAS Author:Green, TJ (Mr Timothy Green)
UTAS Author:Powell, MD (Dr Mark Powell)
UTAS Author:Harris, JO (Associate Professor James Harris)
UTAS Author:Butler, R (Dr Rick Butler)
ID Code:32833
Year Published:2005
Web of Science® Times Cited:3
Deposited By:TAFI - Aquaculture
Deposited On:2005-08-01
Last Modified:2006-04-01

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