| Summary: | The structure provided by a wastewater outfall pipe may be attractive to a variety of marine fishes, yet previous studies that address the risks associated with exposure to wastewater effluent rarely account for the movement patterns of the species studied. This study used acoustic telemetry (Vemco Positioning System, VPS) to quantify the movement patterns and habitat association of several demersal species (Citharichthys sordidus (Pacific sanddab, PS, n = 59), Pleuronichthys verticalis (Hornyhead turbot, HT, n = 17), Parophrys vetulus (English sole, ES, n = 13), and Sebastes miniatus (Vermilion rockfish, VR, n = 55)) at two sites (near the Orange County Sanitation District, OCSD, wastewater outfall and at a reference site) in southern California over a one year period. Residencies to the OCSD outfall site and reference site were low for the three pleuronectiform fishes (PS, HT, ES, less than 10% of the total study duration was spent in either site), which indicates that these species exhibit nomadic movement behavior. Alternatively, VR showed a higher degree of residency to the outfall site (nearly 40% of the total study duration), with lower residency values during the spawning season (Winter and Spring; Linear Mixed Effects Model, p ≤ 0.003). The nomadic behavior of PS, HT, and ES indicate that individuals are likely using other habitats, with potentially higher levels of sediment-bound contaminants than the OCSD outfall. Therefore, tissue samples from these species may reflect the accumulation of contaminants across several sites, not just the OCSD outfall site. Of the species studied, VR may be the most affected by wastewater effluent, because this species spent significant amounts of time near the diffusing region of the outfall. Results from this study may be adapted for other wastewater treatment facilities to interpret contaminant study results, refine bioaccumulation modeling, and investigate new species to use in future monitoring efforts.
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