Comparing relative abundance and population characteristics of Flathead Catfish across a range of establishment levels at the Susquehanna River

Elaine Langone Center, Room 241

Flathead Catfish were first documented in the Susquehanna River in 2002 downstream of Safe Harbor Dam, York and Lancaster counties, Pennsylvania. Since that time the species has increased in range and abundance throughout the Susquehanna Basin. In 2016, we initiated a study to evaluate abundance and growth characteristics of Flathead Catfish along a gradient of establishment in the Susquehanna River. We used baited, tandem hoop nets at 12 randomly selected locations within each reach to evaluate relative abundance (CPE, catch per effort) and provide individuals for age and growth analysis. Temporal replicates we also set at a portion of the sites to evaluate variability in CPE between sets. Age was determined using lapilli otolith for each fish (n=142) and von Bertalanffy growth estimates determined using R software package to evaluate differences in growth parameters among different levels of establishment. Growth rates were similar among reaches however maximum age and CPE differed among reaches. These data along with other North American populations are currently being used to evaluate factors affecting population characteristics to inform management of both native and nonnative populations in Pennsylvania and elsewhere.