Browsing by Author "Williams, Samuel Mackey"
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- Global phylogeography of sailfish: deep evolutionary lineages with implications for fisheries managementPublication . da Silva Ferrette, Bruno Lopes; Mourato, Bruno; Vieira Hazin, Fabio Hissa; Arocha, Freddy; Williams, Samuel Mackey; Rodrigues Junior, Carlos Egberto; Porto-Foresti, Fabio; de Amorim, Alberto Ferreira; Rotundo, Matheus Marcos; Coelho, Rui; Hoolihan, John P.; Sow, Fambaye Ngom; Diaha, N'guessan Constance; Romanov, Evgeny, V; Domingues, Rodrigo Rodrigues; Oliveira, Claudio; Foresti, Fausto; Mendonca, Fernando FernandesSince the Miocene profound climatic changes have influenced the biology and ecology of species worldwide, such as their connectivity, genetic population structure, and biogeography. The goal herein is to evaluate the phylogeography of sailfish Istiophorus platypterus between the Atlantic, Indian, and Pacific oceans. Our results evidenced a high genetic diversity and three distinct populations among the ocean basins with limited gene flow among them. In addition, the species is characterized by two deep evolutionary lineages that diverged during the Miocene/Pliocene transition, one of them is circumtropical while the other is restricted to the Atlantic Ocean. These lineages evolved along the successive glacial-interglacial cycles from the Pleistocene and remained isolated from each other in glacial refugium until deglaciation. Assessments of sailfish suggest it may be subject to overfishing and the results herein imply the need to re-evaluate the current stock delimitations and management measures adopted by the Regional Fisheries Management Organizations, especially in the Atlantic and the Indo-Western Pacific oceans to effectively manage the species. In addition, this work highlights that both lineages should at least be treated as two distinct management units in the Atlantic Ocean until their taxonomic status is fully resolved, given their high genetic divergence.
- Seascape genomics and phylogeography of the sailfish (Istiophorus platypterus)Publication . Ferrette, Bruno Lopes da Silva; Coimbra, Raphael T F; Winter, Sven; De Jong, Menno J; Williams, Samuel Mackey; Coelho, Rui; Rosa, Daniela; Rotundo, Matheus Marcos; Arocha, Freddy; Mourato, Bruno Leite; Mendonça, Fernando Fernandes; Janke, AxelPermeable phylogeographic barriers characterize the vast open ocean, boosting gene flow and counteracting population differentiation and speciation of widely distributed and migratory species. However, many widely distributed species consists of distinct populations throughout their distribution, evidencing that our understanding of how the marine environment triggers population and species divergence are insufficient. The sailfish is a circumtropical and highly migratory billfish that inhabits warm and productive areas. Despite its ecological and socioeconomic importance as a predator and fishery resource, the species is threatened by overfishing, requiring innovative approaches to improve their management and conservation status. Thus, we presented a novel high-quality reference genome for the species and applied a seascape genomics approach to understand how marine environmental features may promote local adaptation and how it affects gene flow between populations. We delimit two populations between the Atlantic and Indo-Western Pacific oceans and detect outlier loci correlated with sea surface temperature, salinity, oxygen, and chlorophyll concentrations. However, the most significant explanatory factor that explains the differences between populations was isolation by distance. Despite recent population drops, the sailfish populations are not inbred. For billfishes in general, genome-wide heterozygosity was found to be relatively low compared to other marine fishes, evidencing the need to counteract overfishing effects. In addition, in a climate change scenario, management agencies must implement state-of-the-art sequencing methods, consider our findings in their management plans, and monitor genome-wide heterozygosity over time to improve sustainable fisheries and the long-term viability of its populations.