This work is essentially orientated to present an introduction to the mathematical models applied to fisheries stock assessment. There are several types of courses about the methods used in fish stock assessment. One type considers practical application as the main aspect of the course, including the use of computer programs. The theoretical aspects are referred to and treated as complementary aspects. A second type is mainly concerned with the theoretical aspects of the most used models. The practical application, considered as the complementary part, facilitates the understanding of the theoretical subjects
