title: Reproductive Biology of Albacore Tuna (Thunnus alalunga) in the Western Indian Ocean.
abstract: The reproductive biology of albacore tuna, Thunnus alalunga, in the western Indian Ocean was examined through analysis of the sex ratio, spawning season, length-at-maturity (L50), spawning frequency and fecundity. From 2013 to 2015, a total of 923 female and 867 male albacore were sampled. A bias in sex ratio was found in favor of females with fork length (LF) < 100 cm. Using histological analyses and gonadosomatic index, spawning was found to occur between 10°S and 30°S, mainly to the east of Madagascar from October to January. Large females contributed more to reproduction through their longer spawning period compared to small individuals. The L50 (mean ± standard error) of female albacore was estimated at 85.3 ± 0.7 cm LF. Albacore spawn on average every 2.2 days within the spawning region and spawning months, from November to January. Batch fecundity ranged between 0.26 and 2.09 million oocytes and the relative batch fecundity (mean ± standard deviation) was estimated at 53.4 ± 23.2 oocytes g-1 of somatic-gutted weight. The study provides new information on the reproductive development and classification of albacore in the western Indian Ocean. The reproductive parameters will reduce uncertainty in current stock assessment models which will eventually assist the fishery to be sustainable for future generations.
authors.affiliation: Department of Biosciences, Faculty of Science, University of Mauritius, Réduit, Mauritius.|IRD-research unit MARine Biodiversity, Exploitation & Conservation (MARBEC), Fishing Port, Victoria, Mahé, Seychelles.
authors.forename: Zahirah
authors.initials: Z
authors.lastname: Dhurmeea
authors.affiliation: IRD-research unit MARine Biodiversity, Exploitation & Conservation (MARBEC), Fishing Port, Victoria, Mahé, Seychelles.|IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Zudaire
authors.affiliation: IRD-research unit MARine Biodiversity, Exploitation & Conservation (MARBEC), Fishing Port, Victoria, Mahé, Seychelles.|Seychelles Fishing Authority (SFA), Fishing Port, Victoria, Mahé, Seychelles.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Chassot
authors.affiliation: Seychelles Fishing Authority (SFA), Fishing Port, Victoria, Mahé, Seychelles.
authors.forename: Maria
authors.initials: M
authors.lastname: Cedras
authors.affiliation: Ifremer DOI La Réunion, Le Port, Reunion Island, France.
authors.forename: Natacha
authors.initials: N
authors.lastname: Nikolic
authors.affiliation: Ifremer-research unit MARine Biodiversity, Exploitation & Conservation (MARBEC), Sète, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bourjea
authors.affiliation: Department of Agriculture Forestry and Fisheries (DAFF), Cape Town, South Africa.
authors.forename: Wendy
authors.initials: W
authors.lastname: West
authors.affiliation: Department of Marine and Ocean Science, Fisheries and Mariculture, Faculty of Ocean Studies, University of Mauritius, Réduit, Mauritius.
authors.forename: Chandani
authors.initials: C
authors.lastname: Appadoo
authors.affiliation: IRD-research unit MARine Biodiversity, Exploitation & Conservation (MARBEC), Fishing Port, Victoria, Mahé, Seychelles.|Seychelles Fishing Authority (SFA), Fishing Port, Victoria, Mahé, Seychelles.
authors.forename: Nathalie
authors.identifier: http://orcid.org/0000-0001-8464-0213
authors.initials: N
authors.lastname: Bodin
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D049628:Body Size; D005260:Female; D019156:Indian Ocean; D008297:Male; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D012744:Sex Ratio; D014413:Tuna / Q000254:growth & development*