Diversidade e conservação de tainhas (Actinopterygii: Mugililidae) na província Atlântico Sudoeste Tropical: uma abordagem integrativa

Abstract

The world is facing a widespread biodiversity crisis that particularly affects aquatic environments due to overexploitation of fisheries coupled with pollution and habitat loss. A strategy to reduce species loss is to establish protected areas (PA). However, in order for PAs be successful, it is necessary to know the biodiversity that is being protected to designate effective management actions. The Costa dos Corais Environmental Protection Area (APACC) is the largest coastal PA in Brazil, located in the Atlantic Southwestern Tropical province, and one of its objectives is to order fishing activity to reduce its impact. Within APACC, a group of fish mostly targeted by artisanal fisheries is the mullet group. Nevertheless, it is difficult to measure whether those fisheries activities had impacted the natural mullet populations, since several species occur in sympatry in this region and it is challenging to distinguish them using characters of external morphology due to the great similarity among them. In this thesis an integrative approach was used, where data from the GenBank platform and new DNA sequences were used to build a temporally calibrated phylogeny for mullets of the Mugil genus. Furthermore, data of external morphology, DNA barcoding and new generation sequencing by the DArT-seq methodology were used to delimit mullet species occurring in APACC, providing data to support management actions. With these data it was possible to conclude that, although the species have very conserved morphology, they diversified approximately 30 million years ago. It was also possible to corroborate the existence of cryptic species and paraphyly in M. cephalus, M. curema and M. rubrioculus. Data from external morphology, DNA barcoding and DArT- seq confirm the existence of five lineages of mullets in APACC, corresponding to the species: M. brevirostris, M. curema, M. curvidens, M. liza and M. rubrioculus. The historical record of the species M. incilis in the area revealed to be incorrect identification of individuals of M. curema. With the analysis of thousands of genomic markers, it was possible to conclude that there is no interspecific gene flow, as well as there is no barrier to gene flow between individuals collected in 38km apart estuaries. Estimation of the effective population size (Ne) of each species revealed that it has not remained constant over time and was not uniform for all species. Thus, it is suggested that each species should have a different management plan. However, as the identification of species at the time of fisheries landings is hampered by the absence of diagnostic characters, a suggestion is to define, within the APACC, areas where fishery is allowed interspersed with areas of integral protection, ensuring the maintenance of long-term genetic variability of the stocks. This study demonstrates how integrative taxonomy, including molecular and morphological tools, is essential for estimating biodiversity in protected areas, providing important data for the establishment of management and conservation actions.