Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Nels H. Troelstrup, Jr.


Age and growth, Freshwater mussel, Mortality, Pyganodon grandis, Unionidae, von Bertalanffy


Globally, the family Unionidae is the most threatened group of freshwater fauna. South Dakota is well known for its agricultural production, leading to cultural eutrophication from enhanced fertilizers and sediments. This impact can alter species presence, age, growth and mortality. Objectives of this study were to 1) implement the first comprehensive lake survey of freshwater mussels in eastern South Dakota lakes and document distribution, occurrence and relative abundance, 2) evaluate relationships between age, growth and mortality of Pyganodon grandis and lake trophic state. Freshwater mussels were sampled in 2017 from 116 proportionally and randomly selected natural lakes and reservoir basins throughout six major river basins of eastern South Dakota. We sampled a total of 1,789 specimens and nine unique species from two different orders. Mussel abundance was found to be negatively correlated with conductivity and positively correlate with lake transparency, whereas no significant relationships were found between mussel abundance and temperature, pH, dissolved oxygen or substrate particle size. Pyganodon grandis (Giant Floater) was the most abundant and frequently occurring species across all river basins and lake types. We also documented two invasive species during our sampling efforts, Dreissena polymorpha (Zebra Mussel) and Corbiula fluminea (Asian Clam). P. grandis from 21 survey sites were sectioned, aged and growth increments measured. The von Bertalanffy growth equation was utilized to evaluate growth rates and estimate length of natural lake and reservoir mussels. Mortality was assessed by implementing length-at-age keys to determine instantaneous and annual mortality rates. Age ranged from 4 to 11 years across all sampled sites. We found a significant negative relationship between P. grandis age and lake trophic state assessed from lake transparency data (R2= 0.394, p= 0.022). No significant relationships were observed for growth and mortality. There was a marginal significant difference observed in age based on lake type (p= 0.054). Results of this effort suggest that life expectancy is shorter in more culturally eutrophic lake basins and support results reported elsewhere. This study generated the first South Dakota unionid lake survey and future work can entail monitoring sensitive species and invasive species impacts to lakes.

Library of Congress Subject Headings

Freshwater mussels -- South Dakota.
Freshwater mussels -- Effect of water pollution on -- South Dakota.
Lakes -- South Dakota.
Water quality -- South Dakota.



Number of Pages



South Dakota State University



Rights Statement

In Copyright