The average seasonal abundance distribution patterns found during our study (Fig. 3) resembled historically described patterns of Mnemiopsis leidyi in Narragabsett Bay (Kremer and Nixon, 1976).Mnemiopsis biomass concentration was low or undetectable during the cold mouth of November-April and increased throughout the summer and typically peaked sometime in August or September. There was significant inter-annual variation in total abundance (Fig. 4, F= 2.96, P= 0.011), largely driven by a difference between 2006 and 2003 (2003 versus 2006 P= 0.006, all other comparisons P>0.1).