MODELING AND FORECASTING THE FORTNIGHTLY CLADOCERAN ABUNDANCE IN THE SARONIKOS GULF (AEGEAN SEA)

In the present study, we evaluated the ability of dynamic regression o n the basis of its efficiency to model and forecast the fortnightly ab undance of cladocerans during 1989-1993 in a coastal region of the eas tern Saronikos Gulf (Aegean Sea). The following dynamic regression mod el explained 79% of the variability of the transformed cladoceran abun dance during the fitting period (January 1989-December 1992): In (clad ocerans)(t) = 0.4314 In (chlorophyll a)-5.9013 In (salinity) + 8.7760 In (temperature) + 0.2371 ln (cladocerans)(t-20). The model always pre dicted the start and the end of the cladoceran season, and forecasted the cumulative cladoceran abundance during January-December 1993 with an absolute percentage error of 14.5%. The positive effect of sea temp erature and chlorophyll a, and the negative effect of salinity, on cla doceran abundance are all consistent with previous studies. The positi ve relationship between cladoceran abundance at times t and t - 20 app roximates the seasonal cycle of their abundance.