Data from the first presence measurement indicate a clear picture: inshore waters are the first places where Mnemiopsis becomes detectable in Narragabsett Bay at the beginning of the season before it propagates throughout the bay (Fig. 2). This agrees with the findings of Kremer and Nixon (Kremer and Nixon, 1976) as well as previous (Costello et al., 2006a) Done on a smaller spatial scale, having only three stations, but with greater temporal resolution using weekly sampling for 2 years. In contrast to previous studies, these new data encompass 7 years over 15 stations. These data have allowed us to identify new source regions in addition to the previously studied Greenwich Cove, located west of our station 3 (Costello et al., 2006a).