Movement and home range of the Sickle Darter (Percina williamsi) in the upper Emory River of Tennessee, USA.

Understanding movement patterns and home range of rare species is challenging, especially aquatic fauna like fishes. The Sickle Darter Percina williamsi is a rare fish species endemic to the upper Tennessee River basin in eastern Tennessee, southwestern Virginia, and western North Carolina (USA). It has been listed as threatened by the states of Tennessee and Virginia and is being petitioned for federal listing under the United States Endangered Species Act. Little is known about the movement and home range of this species. A total of 8 Sickle Darters from the upper Emory River system were implanted with 8-mm PIT tags and released at the point of capture. The mean (± SD) total length and weight of all fish PIT tagged was 70.1 ± 3.4 mm and 3.08 ± 1.4 g. Movement of individuals was tracked every 2 weeks for 6 months (September–March) with a Biomark® HPR Plus reader and BP Plus portable antenna. Associated environmental data were collected throughout the study. Mean total effort for all the tracking events was 70 ± 39.4 min, mean catch-per-effort was 9.3 ± 6.6 (min/detection) and mean (± SE) detection was 69.5 ± 12%. Mean (± SD) distanced moved of all individuals throughout the study was 7.1 ± 4.5 m. Best sub-sets regressions modelling suggest that Sickle Darter movement is related to discharge (m/s3) at multiple temporal levels (1, 3, or 7-day). Home range for individuals varied in size. Median home range size was 157.5 (86.0–312.5) m2 and median (range) degree of overlap for estimated home range was 23.3 (6.2–34.0) %. The results from this study suggest that Sickle Darters exhibit strong site fidelity except when discharge is extremely high. Therefore, conservation measures that protect or attempt to reconnect fragmented habitats will need to factor in the low dispersal ability of this species. [ABSTRACT FROM AUTHOR]