Browsing by Author "Mendonca, Fernando Fernandes"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- 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.
- High connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: highlights for conservationPublication . da Silva Ferrette, Bruno Lopes; Mendonca, Fernando Fernandes; Coelho, Rui; Vasconcelos de Oliveira, Paulo Guilherme; Vieira Hazin, Fabio Hissa; Romanov, Evgeny V.; Oliveira, Claudio; Santos, Miguel Neves; Foresti, FaustoAmong the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity pi = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index phi(ST) = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.