A Survey of the Fishes and Habitat of the White River, South Dakota

This survey was the first comprehensive assessment of the fishes and habitat of the White River in South Dakota. The primary objectives were to 1) document the current species composition, relative abundance, distribution, and condition of fishes, and 2) quantify baseline physical habitat conditions. During July and August of 1998 and 1999, physical habitat was measured and fishes were sampled at eleven study reaches between the Nebraska border and Lake Francis Case. I sampled a total of 4,015 fishes representing 20 species and five families. Cyprinids (74%) and Ictalurids (23%) were the dominant families and 79% of the catch was made up of flathead chub Platygobio gracilis (44%), channel catfish Ictalurus punctatus (22%), and plains minnow Hybognathus placitus (13%). Sturgeon chub Macrhybopsis gelida, were found at 10 study reaches and composed 4% of the fish community. Excluding incidental species, 94% of the fish species were native to the White River. The Morisita-Horn index of community similarity indicated that the fish community was similar between years (CmH=0.9519) and among segments (CmH=0.8773 – 0.9648). Mean relative weights of channel catfish were 97 for sub-stock, 79 for stock-quality, and 85 for quality-preferred length groups. Mean back-calculated length of channel catfish at age-1 through age-3 was lower than all other regional populations. This study took place during a wet cycle and physical habitat conditions indicated a biologically stressful environment. Water temperature often exceeded 30 °C and daily temperatures varied by as much as 10 °C. Turbidity ranged from 160 to 768 NTU, and increased in a downstream direction from reach one to eight, at which point turbidity decreased as a result of dilution from the Little White River. Runs and riffles were the dominant macrohabitats and instream fish cover (i.e., woody debris, undercut banks, and large substrates) was rare. Width to depth ratios indicated three distinct river segments that had different channel characteristics. Land use was primarily pasture (59%), and animal vegetation use was low (85%) or medium (11%) at the majority of transects. The fish and habitat data provided by this study will enable fisheries managers to contribute to watershed management planning and allow future researchers to monitor the fish community by repeating my methods under similar hydrological conditions