The effects of desalination brines on Crassostrea virginica (Gmelin)

Abstract

The effects of seawater diluted desalination brines on juvenile and adult specimens of C. virginica have been assessed using long-term seasonal bioassay tests (60 days). The most critical factor affecting the survival and reproduction of the oysters was the relatively high copper content of the brines. Both juvenile and adult oysters were adversely affected by copper concentrations in the range between 19 and 43 μg Cu l−1 of which about 60 per cent was a soluble fraction. The modified seawater parameters caused by the presence of the brines augmented the natural infection levels of the pathogen fungus Labyrinthomyxa marina on adult oysters. The bioaccumulation of copper by C. virginica was found dependent on the metal concentration and the physiological activity of the organisms. Relatively high copper concentration on the oysters tissues inhibited spawning. Copper depletion rates and recovery experiments were also performed at the end of the bioassay tests, by returning the oysters to their natural habitat.