Fuzzy Modeling of the Weight - Length Allometric Relationship of the Fish Species Plagioscion Squamosissimus

Abstract

As part of a project to iniciate an Enviromental Engineering undergraduate student in the scientifict world of advance researchers, the purpose of this study is to model the allometric relationship between weight and length of the species Plagioscion squamosissimus, a Brazilian Cerrado region fish, commonly known as Cerrado croaker. This fish, among other species, is the reason for the research project “Peixe Vivo” (Fish Alive), launched by a Brazilian company, whose data is the source for this research. The motivation to use the fuzzy set theory comes from the fact that, when the objective is to determine the curve that defines the allometric relation of the fish, the path between the measured weight-length measurement until the simulation of the model is reached, is full of inaccuracies. In order to solve this problem and make the modeling more consistent with reality, an important tool of the fuzzy theory is used: the Zadeh Extension Principle. In this way, a pertinence to the deterministic allometric relation is incorporated, inserting the variations that actually occur in the real data and in the course of the modeling process. As a computational tool, it is used the free software GeoGebra that provides a simple way to develped the model and a simultaneous its graphical interpretation.