We calculated the total annual abundance of Mnemiopsis at each station for each year by plotting its abundance at each sampling date for the entire year, and calculating the area under that curve by considering the area between each pair of sample points to be a trapezoid whose area could be calculated according to the formula สมการ . In this case, the x is the ith sampling date of the year and x2 is the (i+l)th sampling date while y1 and y2 are the biomass concentrations of Mnemiopsis on date x1 and x2, respectively. In doing this, we calculated one value for each station in each year with units of mL*m-3*day(mL referring to mL of M. leidyi and m-3 referring to the volume of seawater filtered)