The location of a station at the inner margin versus the open or exterior waters of Narragabsett Bay was a highly significant predictor of the frequency of first and last seasonal presence (x2= 11.66, p< 0.001), further suggesting that inner margin stations are more likely to have the first or last seasonal presence of Mnemiopsis. On 11 May 2001 and 15 April of 2004 and on 30 March and 11 April of 2005, there were transient appearances between the dates of last and first seasonal presence. These transient appearances occurred twice at stations 1, 2 and 3 (all inshore stations) and only once at stations 5, 7, 8 14 and 15.