Morphometry and Claw Strength of the Non-nativeAsian Shore Crab,Hemigrapsus sanguineus

Abstract

The invasive crab Hemigrapsus sanguineus (Asian Shore Crab) arrived on the northeast coast of the United States about fifteen years ago, and has attained high popu- lation levels at the expense of other resident crabs. Data collected between 1998-2012 at a low-energy, rocky intertidal site in the western Long Island Sound reveal continued Asian Shore Crab dominance. A body of research has suggested several reasons for the success of the Asian Shore Crab, including predation on resident crabs. We coupled mor- phometric data with measurements of claw closure force to model strength as a function of crab size and sex, enabling interspecific comparisons. The model provides indirect support for conclusions of an earlier study that suggested Asian Shore Crab dominance was achieved through predation on juvenile recruits of resident crabs such as Carcinus maenas (Green Crab). Asian Shore Crab males may have had more impact than females on Green Crabs due to the sexual dimorphism of Asian Shore Crab chelae and consequent strength disparity.