Reproductive Dynamics of Iheringichthys labrosus (Lütken, 1874)‎ (Teleostei, Pimelodidae)‎, in the Capivara Reservoir, Paranapanema River, Parana, Brazil

الملخص EN

To study the reproductive dynamics of the mandi-beiçudo, Iheringichthys labrosus, in the Capivara Reservoir, Paranapanema River, Parana, Brazil, specimens were captured trimonthly from March 2001 to July 2004 at four sampling sites.

The sex ratio showed a predominance of females in most of months sampled and the larger length classes.

The majority of the individuals captured showed a standard length between 16 and 22 cm, with a maximal length of 27.5 cm.

The size at first maturity was estimated to be 18.1 and 19.7 cm for females and males, respectively.

Analysis of the temporal variation of the gonadosomatic index (GSI) and frequency of occurrence of gonadal maturation stages of males and females for the months sampled showed that I.

labrosus reproduces during the whole year, with peak reproduction in November and December.

There was a positive correlation between the mean values of GSI and variation in rainfall values, suggesting that this abiotic factor can influence the reproduction of this species.

The mean absolute fecundity was 67274.5 ± 16562.5 oocytes, and the mean relative fecundity was 350.6 ± 186.3 oocytes per gram of total weight.