Length-weight relationships native fish of southern Altiplano: Lauca national park, Chile

Abstract

Two genera of fish, Orestias (Cyprinodontidae) and Trichomycterus (Trichomicteridae), inhabit in the Lauca National Park, UNESCO Biosphere Reserve, located at the Andes highlands in northern Chile. The present study analyzed the length-weight relationship for four native species of Orestias (O. parinacotensis, O. laucaensis, O. chungarensis and O. piacotensis) and two native species of Tricomycterius (T. chungaraensis and T. laucaensis), obtained at seven different localities. Our results showed that the growth coefficient values “b” for Orestias ranged from 2.89 (O. parinacotensis) through 4.04 (O. piacotensis) and Trichomycterus between 2.53 (T. laucaensis in Parinacota wetland) through 3.14 (T. laucaensis in Caquena River). All length-weight relationships were significant (p < 0.01), with r2 higher than 0.82. O. laucaensis, O. piacotensis and T. chungaraensis showed positive allometric growth (b > 3). However, two species O. parinacotensis and T. laucaensis showed negative allometric growth (b < 3). Only O. chungarensis showed isometric growth with b ¼ 3. Intense anthropic activity, exotic fish introduction, and climate change present important risks for a unique endemic fish community of the high Andes.