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Carcinus maenas |
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An introduced species to New England, Carcinus maenas, the European Shore Crab, is limited in distribution only by its preference for sheltered shores (Menger, Bruce, A. & Branch, George M. 2001). Introduced to the Gulf of Maine via the south of Cape Cod, MA in the early 1900s, C. maenas spread northward and reached the Bay of Fundy in the 1950s (Trussell, G.C. & Smith, David L. 2000). It is abundant in the southern Gulf of Maine but density lowers further north in the gulf (Trussell, G.C. & Smith, David L. 2000). It is an aggressive predator that has had a high impact on some of the native species (Menger, Bruce, A. & Branch, George M. 2001). It has been blamed for the rapid evolution of Littorina obtusata due to phenotypically plastic responses in that snail to predation (Trussell, G.C. 1996). It has also been shown to induce thicker shells in Mytilus edulis, a blue mussel found abundantly in New England intertidal communities (Leonard, George H., Bertness, Mark D., and Yund, Philip O. 1999). The crab has specially adapted claws of different sizes made especially for shell opening behavior. The large claw allows for destruction of the outer shell, and the small claw is used as a tool to pick the flesh from crushed prey items (Bertness, Mark D. 1999). They also adapt behavior to suit maximum energy efficiency by selecting for medium sized mussels, balancing energy put out needed to break the shells of molluscs and energy taken in, which is dependent on the size of the mollusc being consumed (Bertness, Mark D. 1999). C. maenas has been shown to affect Nucella lapilis populations by impressing changes in spire height and shell thickness on the snail (Steneck, Robert S. & Carlton, James T. 2001). It also feeds on oysters and other young crabs . C. maenas has also been attributed to living in many different salinity gradients, identifying it as potentially being able to disperse to almost any marine habitat (Castro, P. & Huber, Michael E.). Reproduction in C. maenas, like any true crab is a lengthy process. There is an extended period of mating behavior prior to copulation (Bertness, Mark D. 1999). This is due to the fact that mating must be done when the female molts, before her genital pores harden. To facilitate this, males will attach themselves to females for weeks prior to copulation, waiting for her to molt (Bertness, Mark D. 1999). For more information see Kaplan, L.: Http://www.clarku.edu/departments/biology/biol201/lrkaplan
Information for educational purposes only. All
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Adult Carcinus maenas
Small Carcinus maenas
Two Small Carcinus maenas |
