Factors affecting the abundance of age‐0 sport fish in four mainstem Missouri River reservoirs

Abstract

The age‐0 abundance of eight sport fish species in the four mainstem Missouri River reservoirs in South Dakota was evaluated to estimate the influence of environmental and biological factors on age‐0 species abundance. Datasets (at least ten consecutive years) from each reservoir were analysed to evaluate the effects of both monthly (i.e. gauge height, temperature and precipitation) and annual (i.e. cooling degree days and heating degree days, minimum, average, and maximum temperature, and average precipitation) environmental and biological factors. Biological factors including age‐0 prey fish abundance (i.e. gizzard shad Dorosoma cepedianum [Leseuer] abundance), age‐0 sport fish abundance and adult sport fish abundance were examined. Factors were included that are known to have impacts on abundance of age‐0 sport fish in other systems. The abundance of all sport fish species was stable or increasing in all reservoirs, except for walleye Sander vitreus (Mitchell) and white bass Morone chrysops (Rafinesque) in Lewis and Clark Lake. Age‐0 white crappie was the most supported model for explaining age‐0 walleye abundance in Lewis and Clark Lake, and adult white crappie abundance was the most supported model parameter for explaining age‐0 white bass abundance in the reservoir. Findings of the current study highlight the need for species‐specific management of both environmental (i.e. flow manipulation) and biological factors (i.e. harvest limits for sport fish) to increase the abundance of age‐0 sport fish. Due to the dynamic nature of aquatic systems, resulting requirements for management agencies are system‐specific evaluations and management approaches.

Factors affecting walleye and sauger recruitment in Lewis and Clark Lake, South Dakota, 2001–2022

“…Walleye adult abundances in Lewis and Clark Lake were found to be stable from 1987 through the early 2000s (Table S1; Graeb, 2006; Wickstrom, 2003), and increasing during 1984–2016 (Fincel et al., 2019). In addition, age‐0 CPUE of walleye decreased during 2000–2013 (Radigan & Fincel, 2021) and mean adult CPUE of sauger decreased during 1984–2016 (Fincel et al., 2019). Furthermore, we found recruitment synchrony (correlation) between walleye and sauger age‐0 abundances, unlike an analysis of older age‐classes of walleye and sauger in Lewis and Clark Lake (Graeb, 2006).…”