Long-term prediction on Baltic fish stocks based on periodicity of solar activity

Abstract

The methods presently in wide use for the assessment of marine ecosystems and fish stocks cannot provide the high-quality long-term prognoses urgently needed for improved management of marine ecosystems and their fishery resources. A novel method of forecasting the long-term qualitative com- position of ecosystem and fish stocks in the Baltic Sea based on the periodicity and succession of the processes: extraterrestrial factors ? climate chan- ges ? regime forming factors (chiefly salinity and temperature) ? ecosystems ? fish stocks was used in 1989 to predict the approximate year class abun- dances of cod (Gadus morhua callarias), sprat (Sprattus sprattus balticus), sea herring and gulf herring (Clupea harengus membras) in the Baltic Sea for the years 1989-2008. A comparison with actual development up to 2008 show that this prog- nosis was confirmed to a considerable extent. The method based on periodical fluctuations of freshwater input and the thermal regime is described. It predicts a new regime shift in the 2020s to a higher salinity and more acceptable conditions for the organisms of marine origin.