Growth and survival of the oyster Crassostrea echinata in subtidal tray aquaculture, Missionary Bay, Hinchinbrook Island, north Queensland

Five sites within mangrove tidal channels at Missionary Bay, Hinchinbrook Island, north Queensland, were used in a preliminary study of growth and survival of the oyster Crassostrea echinata in subtidal tray culture.

Two sites were located well upstream, had reduced interchange with the coastal water of Missionary Bay, and occupied areas with little fresh water influence. Two further sites were also located well upstream but situated in areas which, from previous experience, were likely to experience significant freshwater influence during the monsoonal periods. The last site was located in a small channel which had direct exchange with Missionary Bay waters and which also was expected to experience lower salinities during the wet season.

240 small oysters were placed at each site on November 15, 1981 and growth and mortality assessed at approximately monthly intervals up to January 1983.

Hydrographic parameters (salinity, temperature, dissolved oxygen, particulate organic carbon and dissolved inorganic nutrients (nitrate, nitrite, phosphate and ammonium)) were obtained concurrently with oyster measurements. Measurements were taken at 10 minute intervals over an approximately 2 hour period from the top of the tide at each site. This sampling periodicity was used in order to estimate the average conditions experienced by the oysters during the high to low tide periods.