Age and growth of diadromous Galaxias maculatus (Jenyns 1842) in southernmost South America (54° S) including contribution of age classes to reproduction

FIGUEROA, D.E.; BOY, C.C.; ROJO, J.H.

ENVIRONMENTAL BIOLOGY OF FISHES

SPRINGER

Lugar: Berlin; Año: 2018 vol. 101 p. 1149 - 1160

0378-1909

The population of Galaxias maculatus studied here, Arroyo Negro (54° S), is located at the southern extreme of the species distribution. This is the first work on growth and other life history traits of a Fueguian diadromous population based on otoliths study.This species is part of the native fish fauna of Patagonia. Furthermore, studies on thegrowth and reproduction of G. maculatus in South America mostly refer to freshwaterpopulations of Andean-Patagonian lakes and rivers (about 41° S). Size cohorts werestudied; age and growth parameters were estimated, the latter using the VBGM. Four sizecohorts were established, and 3+ was determined as maximum age class. No differenceswere found in growth curves between males and females. The 1+ age class was by far not only the most numerous in the population but also the most represented in the reproductivepopulation. The relation between mean TL and latitude was positive (r=0.62) for SouthAmerican populations; however, further studies are needed to determine whether it is thispopulation´s life strategy, the local adaptation of a peripheral population or countergradientgrowth. The results are interpreted in the context of the information available for otherpopulations, and provide important information about the plasticity in life history traits ofthis species.