Abstract
The advantages of biomonitoring in accordance with traditional techniques include: 1.behavioral and physiological responses are more sensitive indicators of contaminant-induced stress, 2. While traditional instrumentation measures specific substances, organisms integrate all stressors to provide an indicator of overall water quality, 3. and if utilizing keystone species the information will help assess impact of the contamination at population and community levels. To effectively use a bioindicator it is necessary to characterize its response and sensitivity (detection threshold) to contaminants. Our goal was to compare the response and sensitivities of the American lobster, Homarus americanus and the blue mussel, Mytilus edulis, to four different heavy metals (CuCl, CrCl3, PbCl2, CdCl2) common in the Great Bay Estuary. In general, detection levels were lower for mussels (0.5ppm CuCl, <1ppm PbCl2, >30ppm CdCl2) than lobsters (1ppm CuCl, 50ppm CrCl3, > 50ppm PbCl2, CdCl2). Clear responsiveness was limited to CuCl which occurred close to lethal levels (for H. americanus 1ppm response, 2ppm LD50). Given these results we would recommend using mussels, due to their higher sensitivity and ease of use. The only drawback is that mussels are sensitive to a variety of other environmental perturbations that can make responses to heavy metals difficult to elucidate.