Composição do ictioplâncton por DNA metabarcoding como ferramenta de avaliação de potenciais áreas de preservação no entorno do Refúgio Biológico de Santa Helena - Lago de Itaipu - PR

Abstract

The Santa Helena Biological Refuge (RBSH) is an Area of Relevant Biological Interest (ARIE) that is part of the municipal conservation units (UC) in the state of Paraná, being a component of the Permanent Preservation Area of Lake Itaipu. It has a total area of 1,482.05 ha, located in the Paraná III Hydrographic Basin in the municipality of Santa Helena, in the extreme west of the state. The UC area covers only the terrestrial environment, the protection of the aquatic environment is only the responsibility of the Buffer Zone area (ZA). Considering that the ZA lacks monitoring, the creation of new restriction areas in the aquatic part around the RBSH becomes essential. Many of these areas are used as a spawning groundf or local and migratory fish species, making them important nursery areas for the ichthyofauna. Conservation approaches involving studies of the early stages of fish life have become increasingly common and important for the implementation of measures to guide and protect these areas. Traditionally, the identification of ichthyoplankton uses classical taxonomy, however, it is extremely difficult to obtain a precise identification, given the imilarity of the specimens at this stage. With the advent of Molecular Biology, the use of specific markers made these identifications more accurate. It is expected that through the DNA metabarcoding technique, it is possible to identify which species are spawning around the RBSH, so that through these data there are subsidies for the expansion of the RBSH preservation area. In this scenario, the ichthyoplankton samples were carried out over a reproductive cycle (2020/2021), distributed in ten essential points in strategic regions of ARIE-SH, in the area of influence of Lake Itaipu, belonging to the Upper Rio basin Paraná. During this period, seven samplings were performed per point, totaling 70 samples. The collected material was subjected to massive sequencing, using the DNA metabarcoding technique with two sets of six primers. The 6,068 eggs / larvae collected resulted in 1,848 viable sequences, allowing the identification of 82 taxa, belonging to seven orders, 26 families and eight subfamilies. This work contributes with the record of 25 identifications at the genus level and 57 at the species level, we also identified the presence of two species introduced from the African continent and five species and four genera of long-distance migratory fish.