Since its itroduction to the New Jersey shore in 1988, the western Pacific shore
crab Hemigrapsus sanguineus has spread to inhabit rocky intertidal locations along the
Atlantic coast from Massachusetts to North Carolina (McDermott 1998). Many reasons
have been proposed to explain the rapid spread of this non-indiginous species. For
example, it has been shown that H. sanguineus has longer spawning periods along the
mid-Atlantic coast than it does in its natural habitat in the western Pacific Ocean, due to
a more favorable climate (Epifanio et al 1998). For this reason, these crabs are able to
spawn more times per season than indigenous crabs, providing one possible hypothesis
For this species to expand its range along the Atlantic coast, it will need to have
wide tolerances to temperature and salinity. In 1998 Epifanio found that
The purpose of this study is to show the tolerance and behavioral responses of H.
sanguineus to varying water and air temperatures, and water salinity concentrations. It is
believed that these crabs will be very tolerant to the various extreme conditions that they
will be put through. It is the ability of these crabs to survive in these unfavorable
situations that is key to their success. This experiment was also designed to prove the
hypothesis that the tolerance of H. sanguineus to various environmental factors increases
In February 2000, a field trip was taken to Crane Neck Point to collect live
specimens for the experiment. The field trip was conducted at low tide. The water
temperature was approximately 3 degrees Celcius, with the air temperature slightly above
freezing (0-1 degree Celcius). Live crabs were obtained by overturning rocks in the
intertidal zone. Hemigrapsus sanguineus was found at all levels of the intertidal zone,
although their numbers increased as one moved toward the waterline. The crabs were
collected wi...