Interannual variation of the biological parameters of silverside Odontesthes bonariensis in Titicaca lake (Peruvian side), period 2009-2015

Abstract

Silverside Odontesthes bonariensis is the second most abundant fishing resource in Lake Titicaca, and has endured intense extractive activity. Given its socio-economic and nutritional importance, a survey with biological information from the 2009- 2015 period has been carried out in four areas of Lake Titicaca (Puno Bay, North Zone, South Zone and Lago Pequeño), in order to know the temporal variations of the biological parameters: gonadosomatic index (IGS), reproductive activity index (IR), condition factor (FC), size-at-first sexual maturity, population structure parameters by size and age and growth parameters. The spawning period lasted from four to six months, mainly in winter. The thermal behavior of the lagoon influences the spawning of the resource, high reproductive indexes were observed in the months when the lake surface temperature registered the lowest values. An inverse relationship was observed between the gonadosomatic index and the condition factor. The species showed better condition in autumn. It was appreciated that the size-at-first maturity varied from 19.9 to 21.8 cm, with a mean of 20.6 cm TL (Total length?) for the study period. The growth was greater in the years 2009, 2014 and 2015, in contrast with the other years assessed.