A Time-Series Assessment of Polycyclic Aromatic Hydrocarbons in Fish Communities Before and After the DWH Event

A time-series assessment of polycyclic aromatic hydrocarbons (PAHs) content in fish communities was conducted in the northern Gulf of Mexico (GoM). Two fish communities (shallow- and deep-water) were examined to determine levels of exposure in contrasting environments and ecologies, to establish baseline levels, and to infer trends in chemical composition before and years after the Deepwater Horizon oil spill (DWHOS). Deep-water mesopelagic fishes (from 25 to 1250 m depth) collected in 2007 contain a baseline level of muscle PAH concentrations of 0.3-1.3 μg/g dry wt, which increased in 2010 and 2011 by up to 10-fold. Similarly, shallow-water reef fishes (from 15 to 80 m depth) collected in summer 2010 have liver PAH concentrations of ~0.3 μg/g dry wt, which increased in fall 2010 and in 2011 by up to 20-fold. Differences in PAH concentrations among feeding behaviors were also observed. For both communities, average concentrations were higher than the established threshold PAH level for adverse biological effects (4.0 μg/g dry wt). After 2012, a decline in the concentration of PAHs was observed reaching values close to baseline levels. Temporal variability of PAH concentrations and composition up to 2015, and its relationships to species composition in both reef and mesopelagic environments will be discussed.