NEW ENGLAND NORTHERN Presence, Abundance, and Characteristics of Green Crabs and Their Effects on Maine Intertidal Community Characteristics

Overview

The intent of this study was to determine the characteristics and impacts green crabs have on Maine rocky intertidal communities. Since the 1960s, the Maine Department of Resources has tracked green crab populations and noticed population increases. The Change in tides creates distinct intertidal zones that are submerged in water and exposed to air for different lengths of time resulting in increased physical stress. Despite challenges and stressors facing organisms in the rocky intertidal, these habitats support a large diversity of life, including the invasive European green crab (Carcinus maenas). This study involved six coastal locations where biodiversity was determined: Simpson’s Index. Green crab populations were caught and observed, and water quality indicators, such as temperature, salinity, dissolved oxygen, and conductivity, were determined. Biodiversity tended to be higher, closer to the low tide line, determined by a correlation test (Sears Island Right r2=0.37, Lamoine r2=0.77, Sears Island Left r2=0.06, Perry r2=0.03, Hulls Cove r2=0.54, Castine r2=0.75). It was found that in rocky intertidal ecosystems biodiversity isn’t significantly impacted by the abundance of green crabs (n=6, r2=0.014). Random sampling of 195 green crabs found that 73.3% were males and 26.7% were females (X2=42.4667, p-value= 7.19*10-11). There was no significant difference between the size of males and females (t=1.4187, df=142, p-value=0.1582). Green crabs are well adapted and are successfully reproducing in rocky intertidal environments. Color distributions are different at each site (X2=261.2875, df=108, p-value=1.015*10-14) Green crabs have invaded rocky intertidal environments: negatively impacting other organisms within those ecosystems.

Competition history

• JSHS 2022 Category not listed

Resources

• National JSHS abstract book ↗

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