NATIONAL PARKS ADMINISTRATION

Director: Dr. Jorge Calvo

Participantes: Dra. Claudia Boy, Dra. Elba Morriconi.

The ‘inanga’ or ‘puyen’, Galaxias maculatus (Jenyns), is one of the world’s most widespread freshwater species in the southern hemisphere, with landlocked and diadromous populations, inhabiting lakes, rivers and sea coasts of Australia, New Zealand, Tasmania and southern South America. The Río Ovando population is one of the most southerly known for this species (54°50_S, 68°34_W) experiencing strong seasonal variations in water temperature (between 0 and 15°C), photoperiod (7-17 h of light) and food availability. G. maculatus in the Rı´o Ovando estuary has an extended reproductive season (from October to February). Both sexes show a high investment in reproduction, in spite of the different pattern of management of available reserves in visceral fat and liver. Visceral fat is accumulated for overwintering more than for reproduction. We consider that G. maculatus in Tierra del Fuego have a differential growth between sexes, with the smaller females maturing at the end of spring.