Response of zebra mussel veligers to chemical oxidants

Experimental studies using chlorine, hydrogen peroxide and ozone showed two responses by zebra mussel veligers. First, veligers readily perceived the presence of oxidants (> 0.1 mg/l for chlorine and ozone) and responded by retracting the velum and ceasing swimming and feeding activities. Under these conditions, veligers are prevented from attaching to solid surfaces. Second, continuous exposure to these oxidants caused death. Complete mortality by chlorine or ozone (0.5-1 mg/l) at 18-22°C required continuous exposure of about 18 and 5 h, respectively. Either chlorine or ozone should be effective in controlling zebra mussel veligers. Hydrogen peroxide was observed to be effective in preventing attachment but only at high doses relative to chlorine and ozone.