Identificação molecular e biologia reprodutiva do Cichla e suas interações morfológicas

Abstract

Several species of Cichla were supposedly introduced in dams, lakes and reservoirs of Brazil causing serious damage to local wildlife. Cichlids captured in Paulo Afonso hydroelectric complex (BA) have uncertain classification due to the fact of not sharing the morphometric discriminant characters and patterns of colorations. This diversity in the form can be attributed to the introduction of more than one species or to the occurrence of hybrids or even may be associated with different stages of gonadal maturation. For the identification of individuals sampled in this study, we used moleculares tools (COI and microsatellites), in addition to morphometric measurements, meristic counts fish and geometric morphometry. Was also performed an evaluation of the reproduction of individuals. Morphometric measurements and meristic counts of fish confirmed the taxonomy of species, but genetic analyses revealed the occurrence of a single species, Cichla monoculus, in the complex. The haplotype analysis pointed to a population that suffered and bottleneck effect in the process of expansion. The different patterns and colors were evaluated with respect to reproductive parameters such as length of first maturity, gonadal gonadossomatic index, and condition factor, stages of gonadal development, fecundity and reproductive period. It was observed a predominance of females relative to males, a reduction in the size of first maturity relative to the natural habitat of the species and a long reproductive period, with peaks of RGS related to rainy season in the region. The morphometry was not allowed to associate the differences of form and colour to the maturational stages. However, a differentiation was observed between the staining patterns for the sample, with the morphotype "gray" with the more elongated body, and with the mouth a lower position compared to the morphotype "yellow". These changes can be attributed to phenotypic plasticity in the environment occupied by cichlids. These morphotypes might be splitting up, there is a crossing between types, through the choice of partner by color, and if the environmental pressure persist, it can lead to speciation of Cichla monoculus.