A new approach to assessing and forecasting the stock of sprat in the Baltic Sea in modern conditions

Abstract

The aim of this article: analysis of information and software for forecasting of the Baltic Sea sprat stock Sprattus sprattus balticus at 22–32 ICES subdivisions in the context of the suspension of Russia’s activities in the International Council for the Exploration of the Sea (ICES).Methods used: The data of estimates of sprat abundance and biomass by hydroacoustic methods, commercial and biostatistical characteristics of the species were used to assess the stock and predict its catch in the Baltic Sea. Estimation of the sprat stock was carried out using the traditional method of virtual population analysis (VPA) adjusted according to the method of extended survival analysis (XSA) using the internationally approved VPA module software within the framework of ICES and the R software environment. The recruitment calibration program RCT3 (Recruitment calibration) was used for the abundance of recruitment (age 1 year) according to XSA and forecast. A multivariate short-term forecast was carried out at different levels of development of the total allowable catch (TAC) under the MFDP program (Multi Fleet Deterministic Projection). As an alternative, the domestic software «KAFKA» was tested.Novelty: for the first time, estimates of the sprat stock were made in the conditions of limited access of Russian specialists to primary data in ICES in full.Result: modern methodological and informational support of scientific research in the Baltic Sea in the conditions of the suspension of the activities of Russian experts in ICES makes it possible to obtain information in the minimum necessary amount for assessing the stock of sprat and predicting its catch. Modeling with the «KAFKA» software showed satisfactory results.Practical significance: The current level of information support for forecasting the state of the stock and catch of sprat in the Baltic Sea will allow solving a complex of problems of managing this resource in modern conditions.