Abstract
In the field of fisheries, one of the key tasks is to determine the total and commercial stocks of fish resources in a water body, as well as to establish the maximum allowable catch of fish to maintain the sustainability of the ecosystem. Mathematical models play an important role in this process, providing effective resource management and predicting fish population dynamics, which ensures the sustainable development of fisheries and the protection of aquatic ecosystems from depletion. The aim of this study is to develop a new mathematical model for assessing changes in fish resource stocks using the cohort method. The work proposes an alternative approach to calculating changes in fish resource stocks based on statistical theory. The model developed in this work represents a new approach to calculating fish resources for practical application, which can be useful for fisheries enterprises and government bodies involved in fish resource management. The advantage of this work lies in the development of a mathematical model based solely on known statistical data and data obtained from fisheries laboratories in the Republic of Kazakhstan. Modern statistical methods were applied to solve the mathematical model, which allow for the identification of unknown factors affecting the dynamics of fish populations, thereby increasing the accuracy of forecasts and the efficiency of resource management.