The diet of the Large Puyén Galaxias platei (Galaxiidae) at Rosario Lake, Patagonia, Argentina

CASAUX R. Y DI PRINZIO C.

Aqua

Aquapress

Año: 2007 vol. 13 p. 77 - 86

0945-9871

Abstract. A total of 1355 Large Puyén Galaxias platei specimens were caught by means of trammel-nets laid on the bottom at Rosario Lake, Argentina. This fish was largely the most numerous species in the catches, followed by the Patagonian Silverside Odontesthes hatcheri 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 Polypedilum sp. Hyalella araucana predominated in the diet throughout the size range of the specimens caught and was almost the only prey in larger individuals, whereas chironomids were important alimentary items in smaller specimens. Galaxias platei preyed intensively on H. araucana throughout the year but seems take advantage of alternative preys, such as chironomids, when available and abundant. The results are compared with previous studies carried out in Patagonia.