Reproductive capacity of an endangered and recovering population of humpback whales in the Southern Hemisphere

• Published in: Marine Ecology Progress Series
• Main Authors: Chero, Guillaume, Pradel, Roger, Derville, Solène, Bonneville, Claire, Gimenez, Olivier, Garrigue, Claire
• Other Authors: Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE Nouvelle-Calédonie ), Institut de Recherche pour le Développement (IRD Nouvelle-Calédonie )-Délégation Ifremer de Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Leibniz Institute for Zoo and Wildlife Research (IZW), Leibniz Association, Kélonia - Observatoire des tortues marines, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: New Caledonia; Pacific population; Recovery; Sexual maturity; Calving interval; Calving rate; Humpback whales; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; Antarctic; Antarctic Peninsula; Pacific; The Antarctic; Antarc*; baleen whales; Humpback Whale; Megaptera novaeangliae
• Online Access: https://hal.science/hal-02924219; https://hal.science/hal-02924219/document; https://hal.science/hal-02924219/file/Chero%20MEPS%202020.pdf; https://doi.org/10.3354/meps13329

International audience Estimating demographic parameters is essential to assessing the recovery potential of severely depleted populations of marine mammal species such as the baleen whales, which were decimated by commercial whaling of the past century. The Oceania humpback whale Megaptera novaeangliae population is classified as endangered by the IUCN because of low numbers and a slow recovery rate. Nevertheless, an anomalously strong increase has recently been detected in the New Caledonia breeding population. To determine the drivers of population growth, reproductive parameters were estimated for the first time for a humpback whale population of Oceania. Based on an extensive monitoring program (1995-2018), recapture histories were reconstructed for 607 females and incorporated in multi-event capture-recapture models. As the females’ ages were generally unknown (87%), 2 models with contrasting age scenarios were investigated. For females of unknown age, the mature scenario assumed maturity at the first encounter, while the immature scenario assumed immaturity within 7 yr after the first encounter, unless the female was encountered breeding. These models respectively resulted in a calving interval of 1.49 yr (95% CI: 1.21-2.08) or 2.83 yr (95% CI: 2.28-3.56) and a calving rate of 0.67 or 0.35. The relatively high calving rate modelled by the mature model is consistent with high pregnancy rates recently observed in the migratory corridors of the Kermadec Islands and on the feeding grounds of the Antarctic Peninsula. Therefore, our results suggest that the recovery of the New Caledonia humpback whale population from past exploitation may be partially driven by an increased reproductive capacity.