Effects of pyrene exposure on sheepshead minnow (Cyprinodon variegatus) reproduction

Polycyclic aromatic hydrocarbons are known to adversely affect survival, growth, and reproduction in many aquatic species. Adult female sheepshead minnow, Cyprinodon varietagus (SHM), were exposed to chronic, low levels of pyrene (12.5, 25, or 50 μg/L nominal concentrations) and the impact on reproductive ability and larval survival was assessed. Viable egg production was significantly reduced in a dose-dependent manner following a 28-d exposure of SHM to pyrene, confirming reproductive dysfunction. Gonadosomatic index (GSI) values were unchanged with pyrene exposure, but histological assessment of ovarian development showed significant differences in reproductive phases in SHM exposed to pyrene for 28 d, with a greater percentage of prespawning and nonspawning females observed in the two highest pyrene concentrations. The percentage of embryos successfully hatching varied significantly among treatments, with lowest hatch occurring at 25 μg/L, but survival of larval fish to 14 d was not significantly different. These results suggest that chronic maternal exposure to low concentrations of pyrene has the potential to affect population structures by altering reproductive development and output as well as embryo/larval survival rates.