SHELL VALVE MOVEMENT RESPONSE OF DARK FALSE MUSSEL, MYTILOPSIS-LEUCOPHAETA, TO CHLORINATION

Shell valve movements of fouling mussel, Mytilopsis leucophaeta, have been studied in the presence of chlorine, using a mussel monitor. Data showed increasing shell valve closure with increasing chlorine concen tration. Shell opening rates of M. leucophaeta at control experiments (0 mg litre(-1) residual chlorine) were about 10 times more than those at 1 mg litre(-1) residual chlorine. Continuous dosing of 0.75 mg lit re(-1) residual chlorine is required before shell movements are critic ally affected. Since current environmental stipulations do not permit this, a level of 0.5 mg litre(-1) has to be used continuously during s ettlement periods of M. leucophaeta for their control. The results als o indicate that M. leucophaeta is more tolerant to chlorine than other mussel species. (C) 1997 Elsevier Science Ltd.