Evaluation of Sandbar Shiner as a Surrogate for Assessing Health Risks to the Endangered Cape Fear Shiner

Abstract

The health status of the endangered Cape Fear shiner Notropis mekistocholas and the suitability of using the sympatric sandbar shiner N. scepticus as an investigative surrogate were evaluated. Forty Cape Fear shiners from three sites and 50 sandbar shiners from five sites were examined. Findings on gill biopsies, fin biopsies, and skin scrapings were limited to low levels of parasitism and gill aneurysms. Eighty-three bacterial isolates representing 13 aerobic species were cultured from the gastrointestinal tracts. A picornavirus was isolated from one pooled sample of sandbar shiners at one site. 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 sandbar) had encysted trematodes, 16% (2 Cape Fear, 12 sandbar) had protozoal aggregates in muscle or connective tissue, and 26% (22 Cape Fear shiners, 1 sandbar shiner) had mild, moderate, or moderately severe hepatic vacuolization. Other microscopic lesions included mild parasitism and degrees of inflammation in various tissues. Sandbar shiners appeared to be suitable surrogates for the Cape Fear shiner in bacteriological sampling; however, parasitic, viral, and nonhepatic histological lesions were more common in sandbar shiners. Findings from this study warrant further investigation of sandbar shiners as a conservative bioindicator species for the presence of potential health risks to Cape Fear shiners.