title: Genetic structure, population demography and seasonal occurrence of blacktip shark Carcharhinus limbatus in Bimini, the Bahamas.
abstract: A longline survey was conducted from 2004 to 2014 to investigate the demographic population structure and seasonal abundance of the blacktip shark Carcharhinus limbatus in the Bimini Islands, the Bahamas. All individuals sampled (n = 242) were sub-adult or adults [70·1-145·1 cm pre-caudal length (LPC) range] with no neonates or YOY recorded in Bimini. Carcharhinus limbatus abundance peaked in September, coincident with the largest ratio of female to male sharks and a peak in fresh mating wounds on females. Mitochondrial control region (mtCR) DNA sequences were obtained from C. limbatus at Bimini to test whether Bimini C. limbatus are most closely related to geographically proximate populations sampled on the south-eastern coast of the U.S.A., the closest known nursery areas for this species. Nine mtCR haplotypes were observed in 32 individuals sampled at Bimini [haplotype diversity (h) = 0·821, nucleotide diversity (π) = 0·0015]. Four haplotypes observed from Bimini matched those previously found in the northern Yucatan (Mexico)-Belize and two matched a haplotype previously found in the U.S.A. Four haplotypes were novel but were closely related to the northern Yucatan-Belizean haplotypes. Pair-wise ΦST analysis showed that Bimini was significantly differentiated from all of the populations previously sampled (U.S.A. Atlantic, U.S.A. Gulf of Mexico, northern Yucatan, Belize and Brazil). This indicates that C. limbatus sampled from Bimini are unlikely from the described, proximate U.S.A. nurseries.
authors.affiliation: South African Shark Conservancy, Old Harbour Museum, Hermanus 7200, South Africa.
authors.forename: K S
authors.initials: KS
authors.lastname: Gledhill
authors.affiliation: Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada.
authors.forename: S T
authors.initials: ST
authors.lastname: Kessel
authors.affiliation: Bimini Biological Field Station Foundation, 15 Elizabeth Drive, South Bimini, Bahamas.
authors.forename: T L
authors.initials: TL
authors.lastname: Guttridge
authors.affiliation: Department of Fisheries Oceanography, School for Marine Science and Technology, University of Massachusetts - Dartmouth, Fairhaven, MA 02719, U.S.A.
authors.forename: A C
authors.initials: AC
authors.lastname: Hansell
authors.affiliation: Molecular Breeding and Biodiversity Group, Department of Genetics, Stellenbosch University, Stellenbosch 7600, South Africa.
authors.forename: A E
authors.initials: AE
authors.lastname: Bester-van der Merwe
authors.affiliation: Pritzker Laboratory for Molecular Systematics and Evolution, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, U.S.A.
authors.forename: K A
authors.initials: KA
authors.lastname: Feldheim
authors.affiliation: Bimini Biological Field Station Foundation, 15 Elizabeth Drive, South Bimini, Bahamas.|Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL 33124, U.S.A.
authors.forename: S H
authors.initials: SH
authors.lastname: Gruber
authors.affiliation: Institute for Ocean Conservation Science/School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, U.S.A.
authors.forename: D D
authors.initials: DD
authors.lastname: Chapman
mesh_terms: D000818:Animals; D001444:Bahamas; D004272:DNA, Mitochondrial / Q000737:chemistry; D005260:Female; D006239:Haplotypes; D008297:Male; D011156:Population Density; D012621:Seasons; D012744:Sex Ratio; D012754:Sharks / Q000235:genetics* / Q000502:physiology
chemical_list: D004272:DNA, Mitochondrial
keywords: control region; elasmobranchs; mitochondrial DNA; philopatry; population genetics