The cause of Barents Sea biomass dynamics

Abstract

The fluctuations of the biomasses in the Barents Sea have been poorly understood and caused problems in biomass management. Better long-term forecasting is thus crucial for an economical and sustainable utilization of the biomass. The present paper presents a wavelet analysis of the Kola temperature series and the biomass time series of Barents Sea Shrimp ( Pandalus borealis), Barents Sea capelin ( Mallotus villosus), Norwegian spring spawning herring ( Clupea harengus), Northeast Arctic cod ( Gadus morhua), and Northeast Arctic haddock ( Melanogrammus aeglefinus). The wavelet shows a close relation between the 18.6-year lunar nodal tide and dominant temperature cycles in the Kola temperature series. It also shows that all biomass time series are correlated to dominant cycles of 18.6/3=6.2, 18.6 and 3∗18.6=55.8 years in the Kola section. This indicates that fluctuations of the temperature and the biomass in the Barents Sea are a deterministic process caused by the lunar nodal cycle. The close relation to the stationary 18.6-year lunar tide opens new possibilities for better forecasting and long-term management. The deterministic relation between biomass growth and the Kola cycles opens a possibility of more optimal management in short-term periods of 6 years, medium-term management of 18 years and long-term management of 55–75 years. The stationary biomass cycles can be represented by a simple phase-clock which indicates the current state of the biomass. This method represents a new possibility of long-term biomass forecasting.