Interactions between northern crayfish (Orconectes virilis) and round gobies (Neogobius melanostomus) and their impact on benthic communities

Northern crayfish (Orconectes virilis) play a keystone role in near shore ecosystems of Lake Michigan and as such have a large impact on the benthic food chains and nutrient cycling within these systems.  This is particularly important in light of a general decline in O. virilis numbers in the study area over the last 6 years. The invasive round goby (Neogobius melanostomus) is well adapted for life in near shore habitats and is an active and voracious predator of benthic organisms. The purpose of this study is to quantify the impact of O. virilis on benthic invertebrates using an exclosure and leaf-pack study in Rowley’s Bay, Lake Michigan.  Treatments were designed to allow qualification of N. melanostomus interactions with O. virilis and to quantify how these interactions influenced benthic invertebrate densities and diversity.  The results indicate a correlation between the presence of O. virilis and both density and diversity of benthic invertebrates. A correlation can also be seen between N. melanostomus density and the density and diversity of benthic invertebrates, including O. virilis.