Freshwater Fish Assemblages and Health Assessments at a Confined Disposal Facility and a Protected Coastal Marsh in Southwestern Lake Erie, USA

Confined disposal facilities (CDFs) are diked structures used to contain dredged materials and prevent their release into the environment. Wildlife species such as freshwater fish that live in these facilities may be affected by contaminants or impaired water quality conditions that impact their health, welfare and conservation. We performed health assessments and characterized freshwater fish assemblages at two sites in southwestern Lake Erie: a CDF at the mouth of the Black River in Lorain, Ohio (LCDF) and a protected coastal marsh near Port Clinton, Ohio (PCM). Over two sampling days at each site, we used fyke nets to capture 2984 individual fish representing 13 species and two hybrid sunfish species. Species diversity and evenness were higher at PCM than LCDF, with only two species found at LCDF: golden shiners (Notemigonus crysoleucas) and goldfish (Carassius auratus). External parasite prevalence, especially of digeneans, was significantly higher at PCM than LCDF (p = 0.013). Estimated total white blood cell counts were higher at PCM than LCDF, but the difference was not statistically significant (p = 0.058). Overall, the golden shiners and goldfish living at LCDF were apparently healthy with low ectoparasite prevalence and unremarkable haematology parameters. Future research here and at other CDFs in this region should further investigate the impacts of dredging on wildlife conservation and ecosystem health.