Estruturação e aspectos reprodutivos da assembleia de peixes de importância econômica na bacia do rio pindaré

Abstract

The hydrographic basin region of the Pindaré River is represented by its relevance in fishing, since they present great diversity of species that constitute food resources for most of the traditional populations, besides supplying several municipalities of the state of Maranhão. Thirteen species of fish from the Pindaré River and eight species of Lake Viana were evaluated for richness, diversity, trophic structure and weight - length ratio of five species commercially exploited at these two sites. The samples were collected through local trade between January 2015 and June 2016. A total of 2308 specimens (1859 from Pindaré River and 449 from Lake Viana) were collected from 4 orders (Characiformes, Siluriformes, Cichliformes and Perciformes) and 9 families (Anostomidae, Serrasalmidae, Curimatidae, Erythrinidae, Cichlidae, Prochilodontidae, Auchenipteridae, Doradidae and Scianidae). The most representative families in the number of individuals collected in the Pindaré River were Auchenipteridae, Doradidae, followed by Curimatidae, Anostomidae, Scianidae, Serrassalmidae, Prochilodontidae, Erythrinidae and Cichlidae. Four food groups (carnivorous, detritusive, piscivorous and omnivorous) were estimated. The biological diversity indexes show that higher values of richness (S) and diversity of species were observed in the Pindaré River, while lower values were observed in the Viana Lake. The results referring to the macroscopic stages of gonadal maturation, recorded occurrence of individuals in the following maturational stages: A = immature; B = maturing; C = spawning capable and; D = regressing. Regarding the growth pattern, all individuals from the Pindaré River presented negative allometry, while two species collected in the Viana Lake presented positive allometry indicating a discrete variation in this environment. The results obtained show that, despite being two environments with different characteristics, they present similarities regarding the composition of fish assemblages, trophic guilds and reproductive aspects