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The entropy as a measure of diversity has been used by ecologists to characterize a community by its stability process. After the introduction of the concept of a fuzzy subset by Zadeh (1965), many definitions of entropies were given emphasizing the subjectivity in evaluations. A pioneering work which relates the classical meaning of entropy (Shannon index) with the modern fuzzy theory was due to De Luca and Termini (1972); Knopfmacher (1975) formulated a generalization of the axiomatics given by De Luca and Termini; Batle and Trillas (1979) obtained a result which is essentially analogous to Knopfmacher’s by considering a finite fuzzy measure space and the Sugeno’s integrals; and Trillas and Riera (1978) introduced the concept of fuzzy algebraic entropics. Analyses the continuity properties for these fuzzy entropies and establishes conditions which guarantee the convergence E(f_n) → E(f), where (f_n) is a sequence of fuzzy sets and E is an entropy.

Presents an optimal strategy for managing crocodile farms. The strategy is illustrated with the case study of Caiman Crocodilus Yacare of the farm Coocrijapan. However, the strategy can be easily transferred to other farms, once sufficient data on their own crocodile stock is gathered. The main advantage of the ideas developed is that they deal with just one parameter: the break‐even point of the process. The underlying assumption of having a single parameter is that there is no seasonal change in prices; that is, the unitary price of food (say, per kilogram) and the unitary price of crocodile hide (say, per square centimetre) remain approximately constant in some currency. This may or may not be true in the local currency of the country that hosts the farm. With this assumption, dimensionless quantities for profit and return are found.