Balancing Fisheries Management and Water Uses for Impounded River Systems

Review of Gizzard Shad Population Dynamics at the Northwestern Edge of Its Range

Melissa R. Wuellner, Brian D. S. Graeb, Matthew J. Ward, and David W. Willis

doi: https://doi.org/10.47886/9781934874066.ch42

Abstract.—Gizzard shad Dorosoma cepedianum is widely distributed in North America, and South Dakota marks the northwestern edge of its native range. To date, most research regarding population dynamics of gizzard shad has been conducted in more southerly waters. We reviewed the dynamics and biology of gizzard shad populations in South Dakota and compared this information with that reported for southerly populations. Once predicted to become extirpated in some South Dakota systems because of a lack of recruitment, gizzard shad populations today are naturally recruiting and have actually expanded their range, although adult population densities remain low. Recruitment of adult gizzard shad varied depending on the system. One population of gizzard shad introduced into a U.S. Bureau of Reclamation reservoir in western South Dakota exhibited erratic recruitment patterns, with only three age-groups recruited from 1993 to 2004. In contrast, adult gizzard shad samples collected in two Missouri River reservoirs indicated more consistent recruitment over an 8-year period. Peak abundance estimates of larval gizzard shad varied widely by system and by year. From 2004 to 2006, densities of gizzard shad in three western South Dakota reservoirs varied between 3 and 722 fish/100 m3. Densities of gizzard shad in Missouri River reservoirs in 2004 and 2005 varied between 6 and 24,640 fish/100 m3. Production of gizzard shad in South Dakota reservoirs may equal or exceed that of southern systems. When available as prey, age-0 gizzard shad are an important component of predator diets (30–100% by weight of all prey consumed by walleyes Sander vitreus). Introduction of gizzard shad resulted in increased growth rates for recreational fishes in western South Dakota. Currently, the presence of gizzard shad in South Dakota is considered to be a benefit to recreational fisheries in the state. However, further research should address the relationship between climate and reservoir operation on gizzard shad dynamics and the interactions between age-0 shad and age-0 Micropterus, Perca, and Sander spp.