Description

SINGLE PAPER

Volume 13, Issue 2 – 8 November 2007

Ricardo Jorge Casaux and Cecilia Yanina Di Prinzio: The diet of the large puyén Galaxias platei (Galaxiidae) at Rosario Lake, Patagonia, Argentina, pp. 77-86

Abstract

In total, 1,355 large puyén (Galaxias platei) specimens were caught using trammel-nets laid on the bottom of Rosario Lake, Argentina. This fish was the most numerous species in the catches, followed by the Patagonian silverside (Odontesthes hatchery) and the rainbow trout (Oncorhynchus mykiss). The analysis of 333 stomach contents indicated that G. platei is a generalist and opportunistic feeder, preying mainly on benthic organisms. The amphipod Hyalella araucana was the main prey, followed by the chironomids Ablabesmyia sp. and Polypodilum sp. Hyalella araucana predominated in the diet of fish of all sizes and was almost the only prey item in larger individuals, whereas chironomids were important alimentary items in smaller specimens. Galaxias platei preyed intensively on H. araucana throughout the year but seemed to take advantage of alternative prey species, such as chironomids, when they were available and abundant. The results are compared with previous studies carried out in Patagonia.