Seasonal variation in the length-weight relationship of Rhamdia quelen in the Una do Prelado River at the Juréia-Itatins Ecological Station (Peruíbe, SP)

Abstract

This study evaluated the seasonal variation in the length-weight relationship and somatic growth pattern of Rhamdia quelen in the Una do Prelado River, at the Juréia-Itatins Ecological Station, São Paulo State. A total of 132 specimens were collected at eight sampling points using gill nets between March 2024 and February 2025. The length-weight relationship showed seasonal differences, with summer being different from other seasons. The growth pattern was predominantly positive allometric, but was differentiated in spring (negative allometry). These variations may be related to reproduction, food availability, and/or the adaptive plasticity of the species.