Comparative morphological and transcriptomic responses of three estuarine fish species developmentally exposed to environmentally relevant concentrations of PFHxS

Individual contaminants are commonly present in the environment at concentrations below those known to be associated with obvious effects on organism health and survival. This is especially true of per- and polyfluoroalkyl substances (PFAS), which are continuously released to coastal habitats at low concentrations. The implications of PFAS contamination in estuaries remains poorly understood in spite of their crucial role as nursery habitats for United States commercial fisheries. Herein, we describe molecular and sublethal effects observed in three species of early life stage (ELS) estuarine dependent fishes exposed to an environmentally relevant concentration of perfluorohexanesulfonic acid (PFHxS). Study species included a standard marine model, the sheepshead minnow (Cyprinodon variegatus), as well as two economically and ecologically important large-bodied estuarine-dependent sportfish - the spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellatus). Additionally, a subset of red drum exposures were conducted under hypersaline conditions to evaluate the individual and cumulative effects of these common environmental stressors on developing estuarine fish. A suite of morphological endpoints were evaluated and differentially expressed genes were identified using TagSeq-based transcriptomic profiling. This approach allowed for a cross-species comparisons of the effects of developmental PFHxS exposure on ELS fish fitness at both the molecular and whole organism level. Results contribute to a growing body of literature highlighting the impacts of PFAS contamination on coastal ecosystem health and underscore the importance of using multi-stressor approaches in ecotoxicology studies.