Biologia reprodutiva do peixe ornamental Acará-boari Mesonauta insignis (Heckel, 1840), na região Central de Roraima

Abstract

Most neotropical ornamental fish because of their diversity of color, size and easy captive breeding are commonly sought in the aquarist trade for their economic potential, however there are gaps in knowledge about the reproductive biology of M. insignis in the natural environment. The present study showed us reproductive characteristics of the species, spawning period and size of the first gonodal maturation in two streams located in the Boa Vista region - RR.M. This genus is of small size and has distribution in lakes and streams, it is present in Amazonas, Peruvian Amazon, Bolivian Amazonia, Guiana and Amapá. Monthly collections were carried out between February 2017 and January 2018 in two igarapés in the central region of Roraima, one in the Municipality of Mucajaí and the other in Murupú, where the occurrence of Mesonauta insignis was recorded. For the collection of the individuals we used trawl net measuring 4 meters in length and 2 of width being used in the margin of the igarapés. The species found for the genus was described in the phases of the reproductive cycle and also determined the average length of the first gonodal maturation, weight / length ratio, reproductive period and the condition factor that showed to be related to the seasonality and environmental conditions that are inserted. The study showed that females showed spawning, ie, spawning at different times throughout the year, there was also no difference in proportions between males and females. The Apiaú igarapé located in Mucajaí Municipio presented a larger number of mature females. The observed seasonality of M. insignis suggested a period of high productivity, beginning during the winter (February) phase that remained until early summer (August), reaching a peak in the first months of the rising water phase. The set of reproductive characteristics observed in this study can be understood as indicating that the species presents an opportunistic reproductive strategy, such as small size and a seasonal peak of reproductive activity, choosing the winter for its reproduction.