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    Walters, Barrett, Environmental Science and Studies, Juniata College, 1700 Moore St, Huntingdon, PA, 16652,; Merovich, George, Environmental Science and Studies, Juniata College, 1700 Moore St, Huntingdon, PA, 16652,

    We examined Rusty Crayfish (Faxonius rusticus) within Standing Stone Creek to evaluate nocturnal and diurnal diet during the years 2022 and 2023. We have already dissected and analyzed samples from spring, summer, and fall of 2022 and winter of 2023. Samples from the spring, summer and fall of 2023 are collected and in the process of being dissected and analyzed. Samples were collected during respective 1 PM and 1 AM time periods that correspond with each season of the year within the same day. Rusty crayfish had an increase in stomach contents during the nighttime as compared to the day. This trend was relatively clear across all seasons of the year. Males contained slightly more stomach contents than females during the daytime sampling period. Diets that were analyzed showed small trends which included a large amount of mayflies in the spring and a relatively diverse diet in every season following consisting of plant material, fish scales and bones, and many types of macroinvertebrates. Nighttime samples revealed more macroinvertebrates but there were also more diet samples that were analyzed. Plant material was more common in stomach contents during the summer and fall seasons when aquatic vegetation was the most plentiful. Another component we are adding to the data is how many gastroliths are found and during what season are they the most abundant. The presence of gastroliths is relevant in observing trends in rusty crayfish molting cycles. This study aids in understanding of the impact of invasive crayfish on stream ecosystems.

    Rusty Crayfish, Diet Analysis, Stream Ecosystems