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Salinity Tolerance and Sublethal Effects in Fingerling Murray Cod

Piyapong Chotipuntu, Tom Ryan and Tim O'Brien

CRC for Freshwater Ecology, CANBERRA, AUSTRALIA

THEME: ASFB (Poster)

It is widely recognised that while there has been significant investment in salinity investigations and amelioration works, little attention has been focussed on the impacts of salinity on ecosystems or ecological processes aquatic environments. Although some preliminary work has been done, the sensitivity of Murray cod (Maccullochella peelii peelii) to salinity is relatively undetermined. This study has been carried out to determine the salinity tolerance of fingerling Murray cod by assessing acute, sub-lethal and physiological responses. The tolerant threshold for fingerling Murray cod has been determined at 7 g L-1 TDS (approximately 10,300 EC) and 50% did not survive salinity 14.1 g L-1 (96 hr trial). Test fish maintained relatively stable blood osmotic concentration, oxygen consumption and growth performance in salinity up to7 g L-1. Physical disorders (mainly characterized by corrosive skin syndrome) and mortality were observed at the salinities of 8 g L-1 and higher and fish showed some dehydration in salinity higher than 9 g L-1. The fish showed a slight adaptation to a salinity of 8 g L-1 through a period of time when they were gradually transferred or when salinity fluctuated.