Biologia reprodutiva do Cará-preto Cichlasoma orientale (Actinopterygii: Cichlidae) da Bacia do Rio Curu, Ceará

Abstract

This study aimed at understanding the reproductive tactics of endemic cichlid the semiarid region, Cichlasoma orientale, in order to better understand the reproductive strategies of this kind to be held in an environment with large hydrological variations of the Brazilian semiarid region. This study was divided into three chapters. The first chapter was to focus on achievement of macro and microscopic description and definition of ovarian maturation stages and the degree of development of the kind of oocytes. In the second chapter were described characteristics of the life history of C. orientale, such as population structure, sex ratio, reproductive period, spawning type and size at sexual maturity. In the third and final chapter, we analyzed the different reproductive tactics related to the survival of offspring of species, such as the presence of parental care, body size, fecundity, oocyte size and pattern of spawning. The biological material samples were collected monthly from August 2011 to July 2013 in dam Caxitoré and Curu river, both points located in the basin of the river Curu, semiarid region of Northeast Brazil. The results indicated that the germ cells of C. orientale ovaries present five stages of development and the ovaries and testes have four maturity stages. The species is a multiple spawner due to the presence of different stages of development of oocytes in a mature ovary. Mature gonads were recorded throughout the year, with a peak of reproductive activity during the rainy season in the region. The sex ratio of the species differs from 1: 1, but this difference occurs only in the largest size classes, in which occurs the prevalence of males. Sizes obtained for species of maturity were small (females = 4.04 cm, males = 4.33 cm). The fertility based on the most developed oocytes group ranged 254-3389 (average = 2052 ± 849), increasing in proportion to the standard of female length. The most developed oocytes had a maximum diameter of 1.8 mm. This information characterize the species as having low fertility and sizes of large oocytes, which associated with parental brood care, and the multiple spawning exercised by the species indicates that it conducts high investment in offspring survival skills, rather than the quantity of generated offspring . Reproductive tactics made by C. orientale in the basin of Curu river indicate that this species is owned Guild balance strategy with some modifications that are associated with adaptation to a large water change of environment throughout the year.