PREDICTION OF THE MULLIDAE FISHERY IN THE EASTERN MEDITERRANEAN 24 MONTHS IN ADVANCE

The following stochastic, seasonal AutoRegressive Integrated Moving Average (ARIMA) model is presented (1 - 0.679B1) (1 - B1) (1 - B12)Xt = (1 - 0.951B1) (1 - 0.564B12)et where: Xt = value at month t; Bp is a backward shift operator that is used as follows, BpXt = Xt-p; and et = error term at month t, to forecast 24 months into the future the catches of Mullidae in Greek waters. The model is fitted to the 1964-1984 period, forecasts are produced for 1985 to 1986 and are compared with the actual catches observed during that period. Monthly catches are predicted reasonably accurately within an absolute percentage error (APE) range of 0-24.9% and a mean APE of 10.6% (7.5% for 1985 and 12.7% for 1986). Total observed annual catches in 1985 and 1986 were 3750 t and 4714 t respectively, while the model predicted 3993 t and 4189 t (APE 4.2 and 11.1%, respectively). As Mullidae resources are highly overfished in Greek waters, accurate forecasts can be used by resource managers for the preseasonal adjustment of Mullidae fishing mortality. © 1990.