Development of the surf clam (Spisula solidissima) following exposure of gametes, embryos, and larvae to silver

Abstract

The gametes, embryos, and early larvae of the surf clamSpisula solidissima were exposed to silver at concentrations up to 65 μg/L. All experiments were conducted at 20°C and 30‰ S, and lasted up to 48 hr after fertilization. Forty-five minute exposures of eggs to 16 μg/L or more silver just prior to fertilization in non-silver seawater lead to production of abnormal larvae. Simultaneous exposures of eggs and sperm to silver concentrations up to 21 μg/L for 45 min did not prevent fertilization but did produce abnormal larvae at silver concentrations greater than 6 μg/L. Postfertilization treatments of zygotes, embryos, and larvae lead to fewer abnormalities than prefertilization or fertilization treatments of comparable exposure length and concentration. The greatest numbers of abnormalities and mortalities were observed in continuous exposures, from gametes through fertilization to 48 hr postfertilization. Variability in % normal development was greater in high than in low silver concentrations.