Main Article Content
This article shows different algorithms for estimating parameters in nonlinear models. They are applied primarily to a database of problems classified as difficult. Later, the article shows the behavior of the algorithms for the study of growth in the anchovy and sardine, and males and females of the common hake by adjusting a Von Bertalanffy model. The Cerrato test is applied for growth comparisons between sexes for the common hake. The algorithms are implemented in a MATLAB environment, showing good behavior regarding CPU time, number of iterations and exactitude in the solution found with respect to certified values of the problems in the database.