Comparison of North American Standard and South Dakota Standard Gill Nets on Missouri River Reservoirs in South Dakota

Paired gear comparisons were performed between North American Standard (Standard) and South Dakota Game, Fish and Parks (SDGFP) gill nets on four mainstem impoundments of the Missouri River (Oahe, Sharpe, Francis Case, Lewis and Clark) during July-September 2013 to facilitate a statewide transition to Standard sampling gears.  Differences in catch per unit effort (CPUE), size structure, mesh efficiencies, and diversity were quantified and conversions for relative abundance between Standard and SDGFP gears were developed using regression analyses.  Monofilament Standard gill nets were 24.4 meters long and produced higher Catch Per Unit Effort (CPUE) of Freshwater Drum while 106.7 meter multifilament SDGFP gill nets yielded higher CPUE for Channel Catfish, Sauger, and Walleye.  Standard gill nets selected for larger Channel Catfish, Freshwater Drum and Walleye but SDGFP gill nets selected for larger Smallmouth Bass.  Mesh efficiencies of Standard nets were significantly higher than those of SDGFP nets for Channel Catfish, Walleye, and White bass but analogous for Sauger.  No differences in diversity were detected between gears.   Regression equations with high strength of fit proved useful for converting CPUE data from SDGFP to Standard allowing for continued use of historic data and easing a potential transition to Standard sampling gears.