Ecologia e genética da conservação de meros (Ephinephelus itajara) (Serranidae: Epinephelinae)
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Data
2014-05-29
Autores
Souza, Júnio Damasceno de
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Editor
Universidade Federal do Espírito Santo
Resumo
The fish subfamily Epinephelinae are highly related to marine coastal environments, especially reef habitats. Among Epinephelinae, Goliath grouper (Epinephelus itajara) populations have reduced by excessive fishing and has been severely threatened by loss of breeding habitats (reefs) and growth (mangrove) around its limit distribution along the west coast of the tropical Atlantic.Phylogenetically related to this species are groupers currently are intensively fished in the western Atlantic and the sister species E. quinquefasciatus the eastern tropical Pacific. Population reduction of threats to species conservation to bring long-term due to the decrease in the reproductive capacity by selective capture of large fish, loss of variability and gene flow that ensure suitability for environmental and climatic adversities in evolutionary time. Despite legislation prohibiting fishing for goliath groupers in some countries, illegal taking with morphological mischaracterization is a common practice that difficult or impossible to identify the species. In this respect, molecular techniques have provided important tools for monitoring and surveillance of fishing and become essential in forensic identification of several species. The present study investigates bio-ecological and genetic aspects of ooliath groupers aiming to add information to strategies for conservation of the species along the Brazilian coast. As priority targets three lines of research in order to determine the biological aspects and seasonal frequency of juveniles goliath grouper in mangrove habitat in tropical environments were developed; population genetic characterization of goliath grouper in six localities along the Brazilian coast (Pará, Pernambuco, Sergipe, Bahia, Espírito Santo and Santa Catarina) by mitochondrial markers Cyt b and control region, to assess the aspects of diversity, structure and gene flow of stocks and development of practical molecular marker and low cost to assist in monitoring and control of fishing and other eight groupers species of the subfamily Epinephelinae. This study identified a high frequency of juveniles under goliath groupers between 100 and 300 mm, which did not occur in the main studies in the literature with juveniles of the species. Catches were made throughout all months of the year, with significantly greater frequency in the period that includes the hot rainy season in tropical Brazil, with significantly larger sizes in the transition period between late summer and early winter (cold season and droughts). Comparative studies of juvenilesgoliath groupers in other subtropical environments suggest that mangroves can be and essential nursery habitat for early life stages of the species. The results of population genetics indicate moderate to high haplotype diversity and low nucleotide diversity probably associated with recent colonization, with large number of rare haplotypes predominantly single mutational steps. The data revealed no population structure, however, significant genetic variation for both markers was found between stocks of Bahia with the Espírito Santo despite the geographical proximity, indicating the presence of a barrier to gene flow. Significant genetic variations at control region were observed between Pará and Bahia compared to most stocks.There was no correlation signficativa genetic divergence and geographical distance between stocks analyzed. The development of species-specific primers based on the Cytochrome Oxidase I (COI), applied in multiplex PCR was enable the simultaneous identification of nine species of the subfamily Epinephelinae: Epinephelus itajara, E. marginatus, E. morio, E. quinquefasciatus, Hyporthodus flavolimbatus, H. niveatus, 14 Mycteroperca acutirostris, M. bonaci and M. microlepis. This technique can be used to control commercial fishing and precise identification of target fisheries for the conservation of the species. Despite the necessary prudence in maintaining the ban on fishing of goliath grouper in the Brazilian coast, the measure in the long run will become ineffective without the habitats of mangrove and reef habitats connectivity lifecycle of endangered species are not recovered and fully protected. The conservation of goliath grouper (E. itajara) the long term will depend on the efforts to ensure stability and the demographic events of dispersion and connectivity among populations that maintain genetic variability.
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Epinephelus itajara , Mangrove , Manguezal , Population genetics , Genética de populações , Forensic genetics , Genética forense , Endangered species , Espécie ameaçada , Mitochondrial markers , Marcadores mitocondriais , Reef fish , Peixes recifais , Coastal ecosystems , Ecossistemas costeiros