Hemigrapsus sanguineus, also known as the Asian Shore Crab, was first discovered in North America on the New Jersey coast in 1988.  It now inhabits the North American coastline from Maine to North Carolina (USGS).  It is believed that this species was introduced from its native habitat, which includes the coastlines of Russia, Japan, Korea, and China, to the Eastern United States, via ballast water discharge of transport ships (USGS).  This has been a method of introducing many non-native species as water is pumped into ships to act as ballast and taking along with them larvae and juvenile marine organisms.  When these ships empty their ballast tanks in another location, these larvae are put directly into the new habitat due to a lack of measures to destroy organisms in the ballast water.  Hemigrapsus has done so well along the eastern coast of America for a number of reasons, one of which is that the climate conditions are similar to its native habitat and it is able to tolerate hot New England summers and freezing winters (Lohrer).  H. sanguineus has been increasing in population number ever since its introduction and has the potential to greatly impact the native food webs.  This crab species has a very wide range in its diet so it can outcompete other crabs and intertidal organisms (USGS).  Some studies have shown that Hemigrapsus can in some ways directly compete with other New England crab species like Carcinus maenas (Griffen).  The dietary preferences of Hemigrapsus and Carcinus are very similar with both species feeding on Mytilus edulis, L. obtusata, and L. saxatilis (Tyrrell). Another study showed that Hemigrapsus cause Carcinus maenas to change its habitat.  Hemigrapsus presence causes C. maenas to move out from under rocks into the open habitat (Jensen).  Unfortunately, there is still very little known about Hemigrapsus.  The defining characteristics of the larval stage of this crab in comparison to other crab species were not fully studied until this past year (Kornienko).  It is for this reason that I found Hemigrapsus sanguineus to be an interesting study organism.  By trying to find out where the juveniles of this species live I hope to discover more information as to why this particular invasive species does so well in North America.