Master's Theses



Degree Name

Master of Science (MS)


Many aquatic organisms in North America and the rest of the world are at risk of extinction due to habitat destruction and alteration. While it is important to understand and limit the negative impacts of habitat alterations on aquatic species, we also need to understand the behavioral characteristics of species being threatened. Thus, I documented the movement patterns of the pistolgrip mussel, Tritogonia verrucosa (Rafinesque, 1820), and the abiotic and biotic factors that potentially influence these movements. Once a month from July 2005 to July 2006 I assessed the individual movement of 90 pistolgrip mussels. These individuals were marked with polyethylene shellfish tags and transmitters or coins. Transmitters or coins were attached to aid in the recovery of individuals. Twenty-eight individuals were used in a cage experiment to assess the effect of population density on movement. The remaining individuals were returned to the mussel bed from which they were obtained. During each sample, individuals were recovered, their position observed, and microhabitat evaluated. Microhabitat variables included: substrate composition, substrate compaction, water velocity at the surface of the substrate, water velocity at 6/10 the depth, nearest neighbor measurement, and total depth. Overall, I found that a combination of variables, especially water velocity, water depth, and substrate compaction were associated with distance moved. Despite several high-flow events and significant bed-load transport, pistolgrip mussels remained within the mussel bed, which suggests that mussel beds are relatively stable even during high-flow events. In the future, measurement of other variables and slight changes in study design could further elucidate the reasons that mussels move from one location to another.


William Stark

Date of Award

Spring 2007

Document Type

Thesis - campus only access


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