Length-weight relationship of 12 fish species from streams of a protected area in the Southwestern Amazon, Brazil

Relação peso-comprimento de 12 espécies de peixes de igarapés de uma área protegida no sudoeste da Amazônia, Brasil

Abstracts

Abstract  We analyzed the length-weight relationships of 12 lesser-known fish species sampled in four streams in the Southwestern Amazon, in Acre State, Brazil. Diurnal and nocturnal sampling took place in four streams in 150-meter sessions in March and November 2017. Linear regression was applied using the least squares adjustment method. In total, 867 specimens were collected, representing four orders, ten families, and 12 species. The b coefficient of the length-weight regression ranged from 2.58 to 3.22, and r² from 0.77 to 0.99. Five species had negative allometric growth (b < 3), six had isometric (b = 3), and one had positive allometric growth (b > 3). The length-weight relationship was documented for the first time in 10 of the 12 species – Chrysobrycon hesperus, Knodus smithi, Phenacogaster pectinata, Carnegiella myersi, Pyrrhulina obermulleri, Gymnotus curupira, Brachyhypopomus sullivani, Corydoras cervinus, Denticetopsis seducta, and Bujurquina syspilus. Our results contribute to the knowledge on life cycle parameters of fish species from the Southwestern Amazon.

Keywords:
Amazonian streams; allometry; conservation; growth pattern; isometry