Document Type

Thesis - Open Access

Award Date

2022

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Steven Chipps

Keywords

Endangered Species Fisheries Pallid Sturgeon

Abstract

Pallid Sturgeon (Scaphirhynchus albus) are a federally endangered species experiencing widespread reproduction and recruitment failures. Recruitment failure is hypothesized to be caused by habitat modifications made to the Missouri River that disrupt connectivity and alter temperature profiles downstream of constructed dams. Hypolimnetic releases from Missouri River dams affect the temperature downstream, creating colder conditions during the downstream drifting phase for dispersing larvae. Understanding the influence of water temperature changes on larval development is crucial for recovery efforts. In this study, we evaluated the effects of water temperature daily heating rate on energy use, settling behavior, and growth rate of endogenously feeding Pallid Sturgeon larvae. Test conditions for the experiment spanned a range of heating rates that may occur as water warms longitudinally. Settling rate of larvae was inversely related to heating rate and ranged from 8.25 days post hatch (dph) at 0.4°C day-1 to 5.5 dph at 1.5°C day-1. The difference in drift time at 0.4°C versus 1.5°C day-1 (e.g., 2.75 days) would extend the drift distance by approximately 150 km based on average river velocity. These data were used to develop a predictive model for estimating settling time and drift distance of sturgeon larvae based on temperature and velocity conditions in the Missouri and Yellowstone rivers. Applying the model at two simulated water velocities (0.3 m s-1 and 0.6 m s-1) in the Missouri River predicts that Pallid Sturgeon larvae would drift 163 - 310 kilometers, and have sufficient drift distance between Fort Peck Dam and the headwaters of Lake Sakakawea. When the model was applied to conditions in the Yellowstone River with a simulated velocity of 1.8 m s-1, the predicted drift distance exceeded the length of available drifting habitat resulting in Pallid Sturgeon larvae drifting beyond the Yellowstone River and into the Missouri River above Lake Sakakawea. However, tributaries to the Yellowstone River including the Powder River remain uninvestigated as more potential spawning locations that are now accessible to Pallid Sturgeon. These findings will help inform proposed surface-water releases at Fort Peck Dam to improve larval survival in the Upper Missouri River as well as provide insight into potential Pallid Sturgeon spawning in the newly-accessible Yellowstone River.

Library of Congress Subject Headings

Pallid sturgeon -- Larvae -- Effect of temperature on -- Missouri River.
Pallid sturgeon -- Missouri River.

Number of Pages

85

Publisher

South Dakota State University

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Rights Statement

In Copyright