The effect of salinity on growth and survival of juvenile black bream (Acanthopagrus butcheri)
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Growth and survival of juvenile black bream (Acanthopagrus butcheri) were determined at salinities from 0 to 60 ppt (in 12-ppt increments) and from 0 to 12 ppt (in 4-ppt increments) in two separate trials of 6 and 4 months duration, respectively. Juvenile black bream were able to survive and grow at salinities ranging from freshwater (0 ppt) to 48 ppt. Osmotic stress was evident at 60 ppt, however, survival was not significantly affected. Fish reared at 24 ppt in trial 1 had a specific growth rate of 2.34 ± 0.03%/day, a rate significantly higher only to those fish reared at 60 ppt (2.16 ± 0.04%/day). Growth was greater at 24 ppt in association with the highest food intake and most efficient FCR. Although both food intake and FCR were not significantly higher than those obtained with fish reared at 12, 36 and 48 ppt, the combination of the two factors being optimised at 24 ppt lead to the greatest growth. Analysis of data from the second trial found no significant difference in the growth rate of black bream reared at salinities ranging from freshwater to 12 ppt, with SGR ranging from 1.92 ± 0.05%/day to 2.05 ± 0.02%/day. Variable results in freshwater between the two trials suggested that total hardness of freshwater may influence survival and/or an ontogenetic change in salinity tolerance may occur.
|Publication Type:||Journal Article|
|Copyright:||© 2002 Elsevier Science B.V.|
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