(Georgia Institute of Technology, 2013-04)
McKay, S. Kyle; Batt, Lynnette; Bringolf, Robert B.; Davie, Steven R.; Elkins, Duncan; Hoenke, Kathleen
In 14 major watersheds and thousands of miles of rivers, Georgia’s waterways provide some of the highest levels of aquatic biodiversity in the United States. Hydrologic disconnection by dams, roads, water diversions, and other barriers have led to local declines in both migratory and resident fishes. To counteract these trends, numerous organizations and stakeholders have invested in fish passage structures and dam removal. Techniques for prioritizing barrier improvement, measuring passage efficacy, and designing passage structures are rapidly developing in both research and practice. We review the status of fish passage improvement in the state of Georgia as it relates to two key topics. First, what methods exist (or are being developed) to prioritize barrier improvement? Second, what lessons have been learned from recent fish passage and dam removal projects? We address these questions by way of example projects conducted by a variety of agencies and entities. We conclude by summarizing some emerging challenges and opportunities for future research in fish passage improvement.
(Georgia Institute of Technology, 2011-04)
Kellock, Kristen A.; Bringolf, Robert B.
Recent reports of intersex fish (males with oocytes in their testicular tissue) in water bodies around the world have stimulated widespread concern about the effects that chemicals are having in the environment. Intersex fish have decreased sperm production, decreased sperm motility and decreased fertilization success compared to histologically ‘normal’ male fish. Estrogens and estrogen-like chemicals in the environment are known to induce intersex and other forms of endocrine disruption in fish. To date, a systematic evaluation of the severity and extent of intersex fish has not been completed in Georgia. Therefore, our objectives are (1) assess intersex condition in black bass collected from rivers and lakes across Georgia, and (2) determine spatial and temporal trends in estrogenic potency (a measure of the estrogens and estrogen-like substances) of surface waters. Study sites include the Oconee River and its major tributaries, the Ocmulgee River, the Savannah River and the Broad River as a reference (no major wastewater effluent discharges). Fish and water samples were collected upstream and downstream of municipal wastewater effluent discharges in each river (except Broad River). Fish were also sampled from lakes across Georgia with no major wastewater inputs to determine a natural ‘background’ rate of intersex in fish from relatively unpolluted water bodies. Gonads from all fish were examined histologically the intersex condition and incidence rates were compared among sites. We hypothesize that incidence of intersex fish will be associated with estrogens in surface waters. Potency of estrogens in surface waters will be determined by use of an in vitro yeast-based reporter gene assay. This study will provide the first investigation of intersex fish in many of Georgia’s rivers and lakes and will be the first to investigate the estrogenic potency of surface waters across the state.