Effects of copper on hatching of larvae and prezoea survival of Petrolisthes galathinus (Porcellanidae): assays with ovigerous females and isolated eggs.

Ovigerous females of the porcellanid crab Petrolisthes galathinus were selected for toxicological bioassays. A first assay was made on isolated eggs, exposing them to 0 (control), 0.5, or 1 mgL(-1) copper. Both copper concentrations caused significant mortality just before hatching. The few prezoeas hatched at 0.5 and 1 mgL(-1) were unable to reach the zoea stage. A second assay was conducted on the ovigerous females isolated and exposed to 0 or 0.1 mgL(-1) copper. Females were checked daily and the percentages of mortality, egg loss, and hatching larvae were recorded. No differences in either mortality of females or number of hatched larvae were noted between control and copper-exposed groups. From each of these groups, 15 recently hatched prezoeas were transferred to clean seawater, while another 15 were exposed to 0.1 mgL(-1) copper. The numbers of dead or alive prezoeas, transitional larvae, and zoeas were ascertained every 24 h. Prezoeas hatched from exposed eggs and transferred to clean seawater at hatching showed enhanced mortality and a delay in development, compared with control larvae maintained in clean water throughout. Copper at 0.1 mgL(-1) was lethal to almost all larvae exposed only after hatching, while those that had also been preexposed to copper during embryonic development showed a certain degree of tolerance to copper exposure, at least during the first 24 h after hatching.