title: High connectivity of the crocodile shark between the Atlantic and Southwest Indian Oceans: highlights for conservation.
abstract: Among 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 π = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index ΦST = -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.
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, UNESP, Brasil.
authors.forename: Bruno Lopes
authors.initials: BL
authors.lastname: da Silva Ferrette
authors.affiliation: Departamento de Ciências do Mar, Instituto do Mar, Universidade Federal de São Paulo, UNIFESP, Santos, Brasil.
authors.forename: Fernando Fernandes
authors.initials: FF
authors.lastname: Mendonça
authors.affiliation: Instituto Português do Mar e da Atmosfera, IPMA, IP, Olhão, Portugal; Centro de Ciências do Mar, CCMAR, Universidade Algarve, Faro, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Coelho
authors.affiliation: Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, UFRPE, Pernambuco, Recife, Brasil.
authors.forename: Paulo Guilherme Vasconcelos
authors.initials: PG
authors.lastname: de Oliveira
authors.affiliation: Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, UFRPE, Pernambuco, Recife, Brasil.
authors.forename: Fábio Hissa Vieira
authors.initials: FH
authors.lastname: Hazin
authors.affiliation: Centre Technique d'Appui à la Pêche RéUNionnaise (CAP RUN), Association Réunionnaise de Développement de l'Aquaculture (ARDA), Le Port, Île de la Réunion, France.
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Romanov
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, UNESP, Brasil.
authors.forename: Claudio
authors.initials: C
authors.lastname: Oliveira
authors.affiliation: Instituto Português do Mar e da Atmosfera, IPMA, IP, Olhão, Portugal.
authors.forename: Miguel Neves
authors.initials: MN
authors.lastname: Santos
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, UNESP, Brasil.
authors.forename: Fausto
authors.initials: F
authors.lastname: Foresti
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D003247:Conservation of Natural Resources; D005398:Fisheries; D019156:Indian Ocean; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012754:Sharks / Q000235:genetics*