Environmental DNA (eDNA) has been proven as an effective tool for the detection and monitoring of absence or presence of rare and invasive species. Furthermore, eDNA analysis has been used to quantify biomass in vertebrates, particularly fish species. However, this has rarely been studied in invertebrates. This study tested whether eDNA can be used to determine the biomass of the world-wide invasive green crab, Carcinus maenas. In a controlled lab study, we tested how biomass affects the eDNA concentration collected in context of different biotic and abiotic parameters. Our data show that eDNA concentration did not correlate with biomass, as it did with vertebrate species. When incubating 1, 3, or 6 crabs in 4 gallons of sterile saltwater for 1 to 7 days no dose-response effect was observed. eDNA concentration peaked around day 3, indicating time-dependent shedding and degradation events affecting the respective data. Temperature, motor activity, and aggression levels were varied and were shown to also impact the concentration of recovered eDNA. Our results show that biomass, temperature, activity, and potentially many more parameters affect shedding and degradation rates for eDNA, which impact the recoverable eDNA concentration. Therefore, eDNA analysis cannot be used to reliably determine the biomass of the invasive invertebrate species C. maenas. Funded in part by NSF EPSCoR Maine eDNA grant# 1849227.