"Brook trout_ Salvelinus fontinalis_ is the native salmonid in the "
Do sculpins really need to move? Movement of Potomac sculpin Cottus girardi in Smith Creek, Rockingham County, VA. Jeremy Shiflet 1, Morgan Hyatt2 and Mark Hudy 3 1 Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0321 2 Randolph-Macon College, Ashland, VA 3 USDA Forest Service, Fish and Aquatic Ecology Unit, James Madison University, Harrisonburg, VA 22807. Abstract--- We evaluated movement and re-colonization rates of Potomac sculpin sampled from eight habitat reaches (90-meters each) on Smith Creek, a stream heavily impacted from agriculture and dominated in species abundance by Potomac sculpin (mean 129/100m2). Four of the sampling units had all fish removed from the middle 30 meters (Treatment: T1). A total of 3,335 Potomac sculpin were marked in the original samples (June 2005) and 665 (19.8%) sculpin were recaptured (July 2005) approximately 30 days later. Most of the recaptured Potomac sculpin were “stayers” (81%). Upstream movers (17%) were greater than downstream movers (3%). However, individual tagged fish moved upstream up to 1,300 meters. The presence or absence of fish in adjacent 30 m habitat sections influenced upstream movement of Potomac sculpin. T1 sections (fish removed from middle sections) averaged 8.5% upstream movement while T2 sections (no fish removed from middle section) averaged 2.6% upstream movement. There were no statistical differences in the downstream movement of Potomac sculpin the between the two treatments. T1 sections averaged 0.8% while T2 sections averaged 1.0%. There were no differences in length between “movers” or “stayers”. Treatment sections where all fish were removed were re-colonized in 30 days to baseline numbers with similar length frequencies. Student Paper, Presenter: Jeremy Shiflet A predicative model for Brook trout Salvelinus fontinalis populations within subwatersheds of the eastern United States T. Thieling1, M. Hudy1, N. Gillespie2, E. Smith3 1 U.S.D.A. Forest Service; Fish and Aquatic Ecology Unit, James Madison University, Harrisonburg, VA 22807 2 Trout Unlimited, Arlington, VA 3 Virginia Polytechnical Institute, Blacksburg, VA 24061 Abstract. -- We summarized existing knowledge regarding the distribution and status of self-sustaining populations of brook trout Salvelinus fontinalis across their native range in the eastern United States (east of Ohio), a region that represents approximately 25% of the species native range and 70% of the native range in the United States. Based on known and predicative models our results show that brook trout are Intact > 50% in 1,612 subwatersheds (30%), Reduced > 50% in 1,938 subwatersheds (37%) and are Extirpated from 1,451 subwatersheds (28%) from their potential (historic) range within the study area. Brook trout are known to be absent in another 277 subwatersheds (5%), but it was not known if they were extirpated or never occurred in these subwatersheds. Six core subwatershed and subwatershed water corridor metrics (% total forest, sulfate and nitrate deposition, % mixed forest in the water corridor, % agriculture, road density and latitude) were useful as predictors of brook trout distribution and status. Intact populations of brook trout are more likely to in subwatersheds where the percentage of total forest was greater than 68%. Continued habitat loss associated with land use practices, existing and new populations of naturalized exotic coldwater and warmwater fishes threaten remaining brook trout populations. Student Poster: Teresa Thieling Age, growth and population dynamics of Potomac sculpin Cottus girardi in Smith Creek, Rockingham County, VA. Allison Watts and Mark Hudy USDA Forest Service, Fish and Aquatic Ecology Unit, James Madison University, Harrisonburg, VA 22807. Abstract--- We evaluated population densities and age and growth of Potomac sculpin sampled from eight habitat reaches (90-meters each) on Smith Creek, a stream heavily impacted from agriculture. Potomac sculpin had an average population density of 129/100m2 (range 30/100m2 to 297/100m2 and were the dominant fish in the ecosystem both by numbers and biomass. Potomac sculpin averaged 71 mm in total length (range 49 mm to 127 mm). The majority of Potomac sculpin were less than 3 years old. Student Paper or poster, Presenter: Allison Watts