Movement of Southern Brook Charr in a North Carolina Headwater Stream
Little is known about the genetically distinct southern strain of Salvelinus fontinalis Mitchell (Brook Charr), a species that is likely to be negatively affected by global climate change at the southern extent of its range. We tagged 35 Southern Brook Charr between March and October of 2011 and sampled for movements in May and October 2011 and May 2012. The study site in Ball Creek, NC, was 330 m long, and we sampled 2 ancillary 50-m sites located 300 m above and below the site boundaries. We recaptured a total of 12 fish: 10 fish once, 1 fish twice, and another fish 3 times for a total of 15 recaptures. Individuals recaptured in spring 2011 moved an average of 9 m downstream, whereas fish recaptured in autumn 2011 moved an average of 7 m upstream. Fish recaptured in spring 2012 moved an average of 6 m upstream from their locations in autumn 2011. There was no relationship between fish length or growth and either distance or direction moved. In addition, there were no significant differences in length or mass of fish that were recaptured and those that were not. The maximum distance moved by a single fish was 49 m downstream. Our results suggest that Southern Brook Charr in headwater streams may have relatively small home ranges (<20 m), although our conclusions were limited by small sample sizes and a 34% recapture percentage based on individual fish. Given that most populations of Southern Brook Charr occur in small streams above barriers, limited movements suggest that population persistence will depend on satisfactory foraging, shelter, and reproductive habitat types within a relatively small area. These requirements should be a concern for managers given that global climate change will affect ambient temperatures and these populations have limited opportunity for movement and emigration.