Relative growth and length at sexual maturity of Metanephrops rubellus (Moreira, 1903) landed in coast of São Paulo, Brazil

Abstract

The amount of Uruguayan lobster Metanephrops rubellus landed in the state of São Paulo has shown considerable annual variation, at first due to ups and downs in the fishing sector interest. However, biological factors may also be influencing, since little is known about the biology of M. rubellus, and most of the available literature on Nephropidae refer to the Norwegian lobster (Nephrops norvegicus), which is morphologically and behaviorally similar. The morphometric relations found characterize the relative growth of M. rubellus as positive allometric, except for Ct x Cc x Pt and Pa, which showed isometric growth. The length at first maturity (L₅₀) and the length frequencies distribution indicate that fisheries are focusing preferably on the portion of population able to reproduce, saving the immature ones. Due to this and to the biological and behavioral similarity between N. norvegicus and M. rubellus, fishing closure or minimum size of capture are not recommended as fishery management tools. Instead, additional research is proposed in order to define the distribution area and density of population, to establish fishing exclusion areas, which function as reservoirs for replenishment of stocks. It is also essential monitoring the population dynamics parameters, in order to control fishing effort.