Rainbow trout versus brook trout biomass and production under varied climate regimes in small southern Appalachian streams

Abstract

Many Appalachian streams historically dominated by Brook Trout Salvelinus fontinalis have experienced shifts towards fish communities dominated by Rainbow Trout Onchorhynchus mykiss. We used empirical estimates of biomass and secondary production of trout conspecifics to evaluate species success under varied thermal regimes. Trout populations were sampled in 13 Appalachian streams from Maryland to North Carolina during summer 2012, and biomass and production of trout species were examined in relation to habitat and water temperature data. Rainbow Trout and Brook Trout were found co-occurring at three sites, Rainbow Trout populations were encountered at an additional five sites, and Brook Trout populations were also encountered at an additional five sites. Brook Trout co-occurred at one site with Brown Trout Salmo trutta. Biomass estimates for Brook Trout and Rainbow Trout ranged from 0.01 to 1.15 g·m^-2 and 0.35 to 1.60 g·m^-2, respectively. Secondary production estimates for Brook Trout and Rainbow Trout ranged from 0.12 to 1.09 g·m-2·yr-1, and from 0.06 to 7.48 g·m^-2·yr^-1, respectively; thus, Rainbow Trout tended to dominate production in study streams where both species co-occurred. Brown Trout was 1.14 g·m^-2 and production was 1.20 g·m^-2·yr^-1; thus, it also dominated biomass and production compared to Brook Trout. Logistic regressions revealed percent production of Rainbow Trout had a positive relationship with mean minimum winter air temperature (P

Citation

Myers, Bonnie. J.E.; Dolloff, C. Andrew; Rypel, Andrew L. 2014. Rainbow trout versus brook trout biomass and production under varied climate regimes in small southern Appalachian streams. IN: Carline, R.F., and C. LoSapio, editors. Proceedings: Looking back and moving forward. Bozeman, MT. Wild Trout XI Symposium: 127-135 9p.