Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008

Abstract

Data on the catch of Pontic shad in the Lower Danube River Region for the period 1920-2008 were used to make one-component and two-component models. The catch model for Pontic shad showed natural cyclic fluctuations with no sign of population decrease. The oscillation periods were 11.17 years and 9.56 years, which corresponded to solar activity cycles. In addition, as anchovy represents the main food source of Pontic shad in the Black Sea, the catch of anchovy in the Black Sea for the period 1950-2006 was modelled. Pearson's coefficient (cc=0.6785) indicated that 67.86% of the Pontic shad catch was dependent on the anchovy catch during the analysed time period. Besides the necessity for better gathering of data in the Lower Danube River Region on the catch of Pontic shad, there is also a need for more profound studies on this species. It is evident that this valuable fish species requires more attention from fish managers in all countries of the Lower Danube River Region.