Gonadal development in pejerrey (Odontesthes bonariensis) during spawning season in relation with sex steroids and temperature variation in Gomez lake (Pampas region, Argentina).
Fresno, P. S. D., Colautti, D. C., Berasain, G. E. and Miranda, L. A.
Laboratorio de Ictiofisiologia y Acuicultura, Instituto Tecnologico de Chascomus, INTECH (CONICET-UNSAM), Avenida Intendente Marino Km 8.200 (B7130IWA), Chascomus, Buenos Aires, Argentina.
Instituto de Limnologia "Dr. Raul a. Ringuelet" ILPLA-(CONICET-UNLP), Boulevard 120, Casco Urbano, 1900 La Plata, Buenos Aires, Argentina.
Ministerio de Desarrollo Agrario de la provincia de Buenos Aires, Estacion Hidrobiologica, Avenida Lastra y Juarez 7130, Chascomus, Buenos Aires, Argentina.
Gomez lake (34 degrees 39 'S 61 degrees 01' W) is a typical shallow lake of Pampas region placed in the upper area of the Salado river. The most abundant fish species in this lake is the pejerrey (Odontesthes bonariensis) valued due to the quality of its flesh and its attractiveness as a game fish. The aim of this study was to describe for the first time in this pejerrey wild population the gonadal stages during three consecutive spawning seasons (August to December) in relation with sexual steroids and temperature in this lake. In general, pejerrey gonadal development, the gonadosomatic index and the plasma levels of estradiol and testosterone varied in relation to air temperature. During the sampling period, pejerrey females started to ovulate in early August (winter), with a peak in October and ending in December with some of them with atretic oocytes. For males, it was possible to find spermiating animals during the whole spawning season and some arrested animals only in December. Our results confirm the relationship with pejerrey maturation and temperature and can be useful for decision making in the management of this natural resource.
Anais da Academia Brasileira de Ciências 93(2): e20190795 (2021)