Responses of Crustaceans to Contaminant Exposure: a Holistic Approach

Typically, the sublethal effects of exposure to environmental contaminants are assessed by measuring the responses of one, or few, biochemical or physiological systems within organisms. An individualʹs survival potential, however, is determined by the integrated phenotypic response of all its systems working in concert. This concept is illustrated here by reviewing the repertoire of responses at several levels of organization (from the molecular to the behavioural) available to the common shore crab,Carcinus maenas(L.) (Crustacea: Decapoda), during exposure to water-borne copper. Behavioural responses may include avoidance reactions, changes in feeding and mating behaviour, as well as altered locomotory activity. Physiological responses are manifest as alterations in iono- and osmoregulation, circulation and respiration. Cellular responses are reflected in ultrastructural changes, lysosomal alterations, induction of metallothionein and stress proteins, and alterations in the activity of enzymes. Particular attention is focused on the integrated response of the gill since it represents the primary target for water-borne contaminants. It is concluded that to gain a holistic view of the impact of chemical exposure on organisms, the simultaneous measurement of numerous biological variables in a multi-system approach is required. This permits the determination of intra- and inter-specific variability in the repertoire of responses of organisms to chemicals (and other stressors), enabling potential impacts on populations and communities to be better assessed.