The Impact of Early Developmental Exposure to Stressors Related to Individual Fitness in Aquatic Organisms and the Subsequent Reproductive Success and Failure on Populations

The impact of several persistent organic chemical stressors known to primarily impact the early developmental stages of bivalves and finfish. The highest concentrations of these compounds are often present in our waterways, which are nursery areas for shellfish and finfish. It is well documented in aquaculture and aquarium-raised teleosts that even within the same species, strain differences can dramatically alter the dose response and impact fecundity. Such individual variability in reproductive fitness, due to effects on biochemical pathways and cellular physiology, modulates the toxic responses whereby effects could transmit to the population level. Laboratory experiments with field-collected fish demonstrate that exposure history of the specific population from which the individual is obtained can dramatically influence the effective dose response and reproductive success. The sensitivity of the embryonic and early life stages to xenobiotics is due in part to the alteration of synchronization of programed cell movement, the primordial organ formation, and the disruption of programmed biochemical and physiological pathways of growth and development. Even in adult organisms when oogenesis and spermatogenesis are occurring, several compounds can disrupt this process by reducing fecundity and survival of embryos and larvae, by disrupting gonadal structure and function in juveniles and adults, and through interfering with behavior. The impacts of xenobiotics on reproductive success, early life stage survival, and altered hormonal cues at the individual level can dramatically increase mortality and decrease the maximum sustainable yield of a population (NJAES 01202, NIEHS T-32-ES007148).