A comparison of PAH exposure in red snapper (Lutjanus campechanus) around natural and artificial reefs in the northwestern Gulf of Mexico

Red Snapper (Lutjanus campechanus) are an important fishery resource in the Gulf of Mexico (GoM) and are found in abundance around artificial (e.g. oil and gas platforms) and natural habitats (e.g. coral reefs, outcroppings). Polycyclic aromatic hydrocarbons (PAHs), are a small but toxic component of crude oil released into GoM waters through both anthropogenic (e.g., oil and gas activities) and natural (e.g., hydrocarbon seeps) sources. The objectives of this study were to measure and compare PAH concentrations between tissue matrices (liver, gonad, muscle, and bile), by sex and location (e.g., artificial oil and gas infrastructure vs. natural reefs), of Red Snapper collected in the northwestern GoM. In 2016, Red Snapper (n = 88) were collected from natural and artificial reefs to evaluate potential differences in PAH exposures and body burdens. There were no significant results from the biometric analysis or their association with PAH's. Average PAH concentrations were significantly higher (p < 0.001) in livers than in gonads and muscle tissue. No significant differences were found in PAH concentrations between sexes or between structure type for both biliary, liver, or, muscle PAH concentrations, likely due to the close proximity of the natural and anthropogenic sites sampled (within 97 km radius). However, biliary PAH concentrations in fish collected outside of the densely populated oil and gas infrastructure fields had significantly lower PAH levels (p < 0.001). Thus, the scale at which samples are collected and compared is critical to un-derstanding the cumulative impacts of oil and gas activities and underscores the need for further research at multiple scales across the GoM.