Effects of a Catch-and-Release Regulation in Rapid Creek, South Dakota

The objectives of this study were to evaluate adult (≥200 mm) Brown Trout Salmo trutta abundance, biomass, condition and size structure in areas under differing harvest regulations within Rapid Creek, South Dakota, USA during consecutive years.  In 2012 and 2013, three sites were chosen, one inside a catch-and-release area and two under standard harvest limits (five daily, only one over 356 mm).  Each year, sites outside the catch-and-release area contained the highest biomass estimates with maximums of 194 and 306 kg/hectare in 2012 and 2013, respectively.  Condition was negatively correlated with abundance in 2012, but showed no correlation in 2013.  In 2012, pairwise comparison revealed that the site within the catch-and-release area had a significantly larger size structure than both sites under standard harvest regulations.  In 2013, pairwise comparisons revealed that the site within the catch-and-release had a significantly larger size structure than only one of the two sites under standard harvest regulations.  In both years, differences existed in abundance, biomass, size structure and condition between stream sites under different regulations.  However, the differences appeared independent of the management strategies.  It is likely that variables other than harvest, such as habitat, are limiting the Brown Trout fishery in Rapid Creek.