REPRODUCTION DYNAMIC OF THE “PIKE CHARACIN” ACESTRORHYNCHUS PANTANEIRO: AN APPROACH BASED IN ADULTS AND THEIR OFFSPRING

Piazza, Y.¹, Lozano, I.¹, Llamazares Vegh, S.², Lo Nostro, F.¹, Fuentes, C. M.³

¹Lab. Ecotoxicología Acuática, DBBE, FCEyN, UBA - Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA, CONICET-UBA).

² Ins. Inv. Producción Animal (INPA), CONICET- Fac. Cs. Veterinarias. UBA.

³Sec. Estado de Agricultura, Ganadería y Pesca. Dir. Planificación y Gestión de Pesquerías.

yanianp@gmail.com

In river-floodplain systems, water temperature and hydrologic regime play a key role in the reproduction of fish species, influencing the spawning activity and the occurrence of their offspring. The reproduction of “pike characin” Acestrorhynchus pantaneiro (Characiformes), a resident and carnivorous Neotropical fish was evaluated at “El Espinillo” Island Lake, a floodplain water body located in the Lower Paraná River (Argentina). Fish were collected from April 2015 to April 2017 by gillnetting and seining for adults and juveniles, respectively. The spawning chronology was studied from adult gonadal development and compared with the back-calculated birth-date determined from juvenile otoliths reading. During the sampling period, the study of the gonadosomatic index and gonadal maturation rates showed that this pike characin was a partial spawner reproductively active from October to January, when the bankfull stage in the river was reached and water temperature overcame 20 °C, corresponding to spring and summer conditions. During the spring of year 2015 female attained gonad maturation sooner than in the following year, possible related to river water level increase, which was earlier and massive in 2015 compared to the spring of year 2016. Fecundity increased linearly with gonad weight, total weight, eviscerated body mass and standard length (Linear regression analysis, P<0.01). Juveniles´ birth date was consistent with the spawning time based on gonadal maturation analysis, with the highest frequency of birth dates in November.

Palabras clave: ACESTRORHYNCHIDAE, REPRODUCTIVE BIOLOGY, FLOODPLAIN