Comparative Toxicity of Dissolved Metals to Early Larval Stages of Palaemon serratus, Maja squinado, and Homarus gammarus (Crustacea:Decapoda)

Abstract

The acute lethal toxicities of mercury, copper, and cadmium to the first larval stage of the prawn (Palaemon serratus), spider crab (Maja squinado), and lobster (Homarus gammarus) were tested. Chromium was also tested with the prawn. Mortality was recorded after 48 h (for lobster) or 72 h (for other species) incubation at 18°C, and the median lethal concentrations (LC₅₀± 95% confidence intervals) per individual and per mass unit were calculated. The LC₅₀ values were, 74 μg Hg/L, 3,304 μg Cu/L, 1,686 μg Cd/L, 12,486 μg Cr/L for prawn; 72 μg Hg/L, 50 μg Cu/L, 158 μg Cd/L for spider crab; and 48 μg Hg/L, 46 μg Cu/L, 34 μg Cd/L for lobster. Therefore, larvae of spider crab and lobster were markedly more sensitive than prawn to heavy metals and thus more suitable to use in seawater quality bioassays. Of these two species, spider crab is recommended due to its abundance, easier maintenance, and higher fecundity. The mercury LC₅₀ values for different larval stages of P. serratus (zoea I, II, V, and VI) were obtained, and no ontogenetic change in sensitivity to the metal could be detected.