Meeting Abstract
The European green crab (Carcinus maenas) was introduced to the Gulf of Maine in the 1800’s and has since then populated a large proportion of the East Coast. It is understood that a higher density of conspecific predators leads to higher levels of intraspecific competition. Factors such as size of competitors, habitat, and prey density also play a role. However, little is known about conspecific competition of juvenile green crabs specifically, and what resource they prioritize (food vs. shelter). This study aims to better understand intraspecific competition of juvenile green crabs in the Damariscotta River based on competitor density and resource availability. Lab experiments were conducted during the summer of 2017 at the Darling Marine Center. Small (5-10mm) and large (20-25mm) juvenile crabs were placed in artificial settings in either low or high density treatment, as well as with limited or abundant shelter treatment. The proportion of time foraging, sheltering and eating was recorded and analyzed. It is hypothesized that a) smaller crabs will prioritize shelter over foraging, and b) crabs in higher densities will spend less time foraging than those in lower density. Finally, I expect individuals with abundant shelter space to prioritize foraging. Preliminary results show crabs, regardless of size, spend more time foraging than hiding. In higher densities, this remains true. However, when shelter is abundant, larger crabs spend more time hiding than foraging, which is contrary to the behavior of smaller crabs. Once all data has been analyzed, this study aims to inform about the intraspecific dynamics of juvenile green crabs, which may contribute to better understanding the population dynamics of this species.
