Banca de DEFESA: JULIA TOVAR VERBA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JULIA TOVAR VERBA
DATA : 27/08/2019
HORA: 14:00
LOCAL: Sala de Reuniões - Ecologia
TÍTULO:

Seascape effects on commercially important fish populations


PALAVRAS-CHAVES:

Catch-based analysis; fishery; fish stock; effective population size; species distribution modelling;connectivity;SNPs


PÁGINAS: 209
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Fisheries science is characterized by several knowledge gaps that prevent the development of more sound research for fish stock conservation. Understanding how these stocks are spatially distributed and which genetic and environmental characteristics explain this distribution is crucial for fishery planning. In this thesis we describe conservation status, population genetics structure and connectivity, and effective population size of commercially important marine fish in Brazil. The first chapter presents an analysis of catch data for 132 species for 61 years. The results indicate a complex interaction between climatic and biological factors, besides exploitation type, affecting the species collapsing risk. The second chapter, using COI and CytB mitochondrial markers analysis, we identified the population genetics structure and historical demography for 17 commercially exploited marine fish species. Most species presented a lack of environmental barriers to gene flow along the Brazilian coast. However, population structure of Pomatomus saltatrix and Cynoscion jamaicensis results indicate genetic discontinuity due to temperature changes and isolation by distance, respectively. The goal of the third chapter was to identify effective population size variability for two reef species – Lutjanus jocu and Sparisoma axillare – and test the influence of past climatic variability on population size changes. Sparisoma axillare population expanded until five thousand years ago and is mostly stable until today, with a population expansion justified by increase in suitable habitat. For Lutjanus jocu, results suggest that, after a period of population expansion, is has been stable for the last one million years. Habitat suitability for L. jocu is apparently stricter nowadays than in the past, but this change does not seem related to population size. Distribution range of L. jocu is larger than S. axillare (endemic to Brazil), so it might be less susceptible to regional climatic changes. In the fourth chapter, we identified which seascape characteristics explain genetic connectivity patters of S. axillare, by analyzing samples collected in six sites on the Brazilian coast and in the islands of Fernando de Noronha, Abrolhos and Trindade. The results indicate that only Trindade Island population is genetically distinct. We found that seascape factors, as bathymetry and oceanic currents, can be more important to explain genetic variation than geographical distance. The results of this thesis indicate an important effect of environmental variables, such as temperature, oceanic currents and depth, on the vulnerability, connectivity and population size of marine fish in Brazil. However, we found a low environmental effect on species population structure. Our results can be applied for marine planning in the region.


MEMBROS DA BANCA:
Interno - 1678338 - ADRIAN ANTONIO GARDA
Externo à Instituição - BEATRICE PADOVANI FERREIRA - UFPE
Interno - 2319234 - GUILHERME ORTIGARA LONGO
Presidente - 1718747 - PRISCILA FABIANA MACEDO LOPES
Externo à Instituição - RICARDO RODRIGUES DA SILVEIRA FILHO
Notícia cadastrada em: 07/08/2019 14:27
SIGAA | Superintendência de Tecnologia da Informação - (84) 3342 2210 | Copyright © 2006-2024 - UFRN - sigaa08-producao.info.ufrn.br.sigaa08-producao