Impacts of Introduced Round Goby on Aquatic Community Structure in Pennsylvania Watersheds
Round Goby diet analysis was based on 177 fish; 15 fish were not included in analysis due to empty stomachs or fully digested organisms that could not be identified. Round Gobies consumed both benthic aquatic macroinvertebrates, unionid mussels, and sphaeriids. Chironomids comprised a large percentage (greater than 24%) in all size classes. Chironomids were found in the highest number of individual fish and largest averages in all size classes except size class 1. Results indicated that there was not a significant relationship between fish species diversity and mussel species diversity (p = 0.4519, t = -0.81536; df = 5). Likewise, the relationship between mussel diversity and substrate index values were analyzed by using Pearson’s correlation test. Results indicated that there was a significant relationship between mussel diversity and substrate index values (p = 0.04766, t = -2.6101; df = 5). The stomachs of 39 Round Gobies were analyzed using genomic techniques. Of those assessed, two tested positive for unionid DNA. The DNA of Alasmidonta marginata was present in the stomachs of both individuals. While A. marginata comprised the greatest proportion of the sequence reads 93 and 99% respecitively, 7% of the sequence reads mapped to Vilosia fabilis for one individual and 1% mapped to Fusconaia rotunda for the other. Vilosia fabilis is both federally and state endangered.