Genomic and Chemical Markers of Contamination in Young of the Year Bluefish from Contrasting Estuaries

To investigate the effects of habitat degradation on the genomic level, young of the year (YOY) bluefish, (Pomatomus saltatrix) from the highly urbanized Hudson Raritan Estuary (HRE) and the less impacted Mullica River-Great Bay (MRGB) estuary were analyzed for condition, level of PCBs (Polychlorobiphenyls), and pesticides, and compared in a preliminary transcriptomic study. For chemical analysis, whole juvenile fish were freeze-dried, extracted in DCM (Dichloromethane), extracts were cleaned by florisil/alumina/silica column chromatography and size-exclusion HPLC, and quantified by gas chromatography. For transcriptomic analysis, Suppression Subtractive Hybridization (SSH) libraries from the pooled livers of fish from the two sites were constructed to subtract common transcripts and recover cloned expressed sequence tag (EST) transcripts that were putatively more highly expressed in one or the other environment. Transcripts were Sanger-sequenced and identified by bioinformatic analysis. Relative quantitative PCR (polymerase chain reaction) was used to investigate a subset of the selected transcripts. MRGB fish were larger and in better condition than HRE fish. HRE fish had PCB concentrations that were, in sum, about seven times higher than MRGB fish and were more highly contaminated with pesticides including Dichlorodiphenyltrichloroethane (DDT) and its metabolites. Transcripts related to metabolic, transport, immune, detoxification, signaling, and environmental response and additional functions were associated with contrasting habitats and provide gene targets to investigate the hypothesis that the growth and condition of the HRE bluefish may be limited by their poor environmental quality.