We established two criteria to determine the station(s) at which Mnemiopsis was first present during the spring or summer months in Narragabsett Bay: first, no ctenophores were to be detected at any other stations for the previous two sampling cycles. Second, the ctenophores needed to be present at one or more stations for minimally two subsequent sampling cycles. The second criterion was used to eliminate transient appearance events (Costello et al. ,2006a). The monthly temporal scale of sampling was broad relative to transport events from inshore to offshore station (Costello et al. ,2006a) and it was possible for more than one station to be the first site of seasonal ctenophore collection. There are no first appearance data from the 2002 season because ctenophores remained present throughout the winter of 2001-02.