Modelling and forecasting monthly swordfish catches in the Eastern Mediterranean


  • Konstantinos I. Stergiou Laboratory of Ichthyology, Department of Zoology, Faculty of Sciences, Aristotle University of Thessaloniki
  • George Tserpes Institute of Marine Biology of Crete
  • Panagiota Peristeraki Institute of Marine Biology of Crete



forecasting, X-11 census technique, uncertainty, long-term changes, Xiphias gladius, Eastern Mediterranean, Aegean Sea


In this study, we used the X-11 census technique for modelling and forecasting the monthly swordfish (Xiphias gladius) catches in the Greek Seas during 1982-1996 and 1997 respectively, using catches reported by the National Statistical Service of Greece (NSSG). Forecasts built with X-11 were also compared with those derived from ARIMA andWinter’s exponential smoothing (WES) models. The X-11 method captured the features of the study series and outperformed the other two methods, in terms of both fitting and forecasting performance, for all the accuracy measures used. Thus, with the exception of October, November and December 1997, when the corresponding absolute percentage error(APE) values were very high (as high as 178.6%) because of the low level of the catches, monthly catches during the remaining months of 1997 were predicted accurately, with a mean APE of 12.5%. In contrast, the mean APE values of the other two methods for the same months were higher (ARIMA: 14.6%; WES: 16.6%). The overall good performance of X-11 andthe fact that it provides an insight into the various components (i.e. the seasonal, trend-cycle and irregular components) of the time series of interest justify its use in fisheries research. The basic features of the swordfish catches revealed by the application of the X-11 method, the effect of the length of the forecasting horizon on forecasting accuracy and the accuracy of the catches reported by NSSG are also discussed.


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How to Cite

Stergiou KI, Tserpes G, Peristeraki P. Modelling and forecasting monthly swordfish catches in the Eastern Mediterranean. scimar [Internet]. 2003Apr.30 [cited 2023Dec.10];67(S1):283-90. Available from:




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