Evaluation of sandbar shiner as a surrogate for assessing health risks to the endangered Cape Fear shiner

The health status of the endangered Cape Fear shiner Notropis mekistocholas and the suitability of using the sympatric sandbar shiner N scepticus as a n investigative surrogate were evaluated. Forty Cape Fear shiners from thre e sites and 50 sandbar shiners from five sites were examined. Findings on g ill biopsies, fin biopsies, and skin scrapings were limited to low levels o f parasitism and gill aneurysms. Eighty-three bacterial isolates representi ng 13 aerobic species were cultured from the gastrointestinal tracts. A pic ornavirus was isolated from one pooled sample of sandbar shiners at one sit e. Forty-three percent of shiners (12 Cape Fear shiners, 27 sandbar shiners ) had granulomas in various tissues of the body, 26% (6 Cape Fear, 17 sandb ar) had encysted trematodes, 16% (2 Cape Fear, 12 sandbar) had protozoal ag gregates in muscle or connective tissue, and 26% (22 Cape Fear shiners, 1 s andbar shiner) had mild, moderate, or moderately severe hepatic vacuolizati on. Other microscopic lesions included mild parasitism and degrees of infla mmation in various tissues. Sandbar shiners appeared to be suitable surroga tes for the Cape Fear shiner in bacteriological sampling; however, parasiti c, viral, and nonhepatic histological lesions were more common in sandbar s hiners. Findings from this study warrant further investigation of sandbar s hiners as a conservative bioindicator species for the presence of potential health risks to Cape Fear shiners.