Abstract

The acute toxicities of Cu²⁺, Ni²⁺ and Cr(V1) in sea water to larval life stages of the sand crab, Portunus pelagicus, were determined in a laboratory study and compared with published data for the toxicity of heavy metal cations to this species. This showed the relative acute toxicities to be in the order Cu²⁺ > Cd²⁺ ≥ Zn²⁺ > Ni²⁺> Cr(V1). Sublethal effects attributable to exposure to sea water contaminated by some of these cations were investigated for both larval and juvenile crab life stages. The effects quantified were inhibition of larval moulting, increase in the duration of development period, and reduced size achieved by successive juvenile crab instars. In each case, the chronic levels of cation contamination in seawater associated with these effects exceeded the Australian guidelines for the protection of marine aquatic ecosystems, but in some cases the safety margin was less than an order of magnitude. In addition, bioconcentration relationships for Cr were determined on a whole-animal and an exoskeleton basis.