Cooperative Fish and Wildlife Research Units Program: Iowa
Education, Research and Technical Assistance for Managing Our Natural Resources

This project contains two objectives that serve the common goal of understanding Shovelnose Sturgeon movement ecology to better manage flows downstream of Saylorville and Red Rock Dams in order to promote the survival and reproduction of these migratory river fishes and the overall ecosystem integrity in the lower Des Moines River.
The first objective will compare spring migration phenology of Shovelnose Sturgeon using acoustic telemetry in two Mississippi River tributary systems, one with and one without experimental flows. This design will examine how environmental flows influence species movement and may affect the location, timing, and reproduction. Previous research suggests that spring flow pulses facilitate Shovelnose Sturgeon spawning in the Missouri River basin. Research may also monitor the movement of previously tagged Lake Sturgeon, a state species of GCN in Iowa and has been petitioned for listing under the Endangered Species Act. The first objective (also Task 1, (b.)) will relate sturgeon movement and environmental conditions with timing of reproduction by capturing sturgeon eggs and larvae downstream of suspected spawning sites. Eggs and larvae will be identified and enumerated in the lab, including an estimate of stage or age. This data will be utilized in the continued development and refinement of the DSMR AMMP, facilitating achievement of the SRP goals for the DSMR.

A second objective (Task 2) is to monitor behavioral movements and habitat selection in relation to flows and temperature during the summer period when water temperatures are the warmest (July-August). This task specifically aims to advance our understanding of Shovelnose Sturgeon summer movement ecology and spatial variation in water quality during the summer to aid in the implementation of “opportunistic heat wave pulses” (Table 1). This information is needed to adjust flows to reduce the risk of physiological stress that has led to mass mortality events of Shovelnose Sturgeon in the Des Moines River. For example, in 2012 an estimated 37,159 Shovelnose Sturgeon died and it was presumed that the cause was related to low flows and elevated water temperatures >30°C (Hupfeld et al., 2015). An additional sturgeon kill occurred in the Des Moines River this year in early July 2023 when flows were <2,000 cfs. This information will also help more broadly to adapt reservoir management to increase downstream ecosystem resilience as water temperatures are predicted to increase in the future due to climate change. To accomplish these objectives in Phase 2, we will conduct a finer-scale telemetry on the previously tagged Shovelnose Sturgeon during the warmest portions of the year late June-August. While conducting objective 1, we will be able to identify areas of the Des Moines River that may be used by Shovelnose Sturgeon during the summer to avoid physiological stress.