The value of long-term environmental monitoring programs: an Ohio River case study

Abstract

As a subset of environmental monitoring, fish sampling programs have been an important part of assessing the potential impacts of water withdrawals and effluent discharges on fish populations for many years. New environmental regulations often require that adverse environmental impacts to fish populations be minimized. Without long-term field data, population evaluations may incorrectly indicate adverse impacts where none exist or no impact where one is likely to occur. Several electric utility companies have funded the Ohio River Ecological Research Program, which has been in existence for over 40 years and consists of fish, habitat, and water quality studies at multiple power plant sites on the mainstem Ohio River. Sampling includes seasonal night-time electrofishing and daytime beach seining at three upstream and three downstream locations near each plant. The long-term nature of the program allows for the establishment of aquatic community indices to support evaluations of technology performance, the collaborative development of compliance metrics, and the assessment of fish population trends. Studies have concluded that the Ohio River fish community has improved in response to better water quality and that power plant fish entrainment and impingement and thermal discharges have had little or no measureable impact. Through collaboration and the use of long-term data, $6.3 million in monitoring costs have been saved during recent fish impingement studies. The ability to access a multiyear fish abundance database, with its associated data on age, growth, and fecundity, improves the quality of such evaluations and reduces the need for extensive field sampling at individual locations.

Species‐specific effects of subdaily temperature fluctuations on consumption, growth and stress responses in two physiologically similar fish species

“…This may be due to the long duration of the experiment (45 days) where walleye may have become acclimated to the temperature regimes by the time stress responses were measured (e.g., Coulter et al 2015). For example, annual surveys of fish assemblages near power plant thermal discharges (Lohner & Dixon 2013) indicate that a variety of species use these thermal plumes and many are attracted to the effluent, especially during winter (EPRI 2009). We are unclear why plasma protein concentrations were not affected by an increased magnitude of temperature change between the two fluctuating treatments.…”

“…In contrast, some fishes may be attracted to habitats undergoing subdaily thermal changes. For example, annual surveys of fish assemblages near power plant thermal discharges (Lohner & Dixon 2013) indicate that a variety of species use these thermal plumes and many are attracted to the effluent, especially during winter (EPRI 2009). Not only are these fishes experiencing subdaily temperature fluctuations while staying in the thermal plume, movement studies show that some individuals frequently move into and out of the heated waters (Ross & Winter 1981;MacLean et al 1982).…”

Increased population size of fish in a lowland river following restoration of structural habitat

“…One strategy increasingly applied is to shift effort from monitoring many smaller interventions to assessing fewer, longer‐term restoration projects and investing more resources into well‐designed monitoring programs (Callahan , Lindenmayer et al. , Lohner and Dixon ). This approach assumes that learning from a few well‐monitored interventions will provide more robust evidence for effective application of the interventions elsewhere (Swirepik et al.…”

Can data from disparate long-term fish monitoring programs be used to increase our understanding of regional and continental trends in large river assemblages?

“…Improvements in water quality regulation and policy associated with the CWA have been cited in other river systems as being a driver of positive changes in fish assemblages. For example, Lohner and Dixon [ 74 ] suggest that improvements in Ohio River fish populations coincide with water quality improvements resulting from the CWA. However, in the UMR, the effects of the CWA on fish assemblages may be less clear because of the confounding effects of other factors affecting fish assemblages.…”