Factors affecting adult body condition in the endangered northern rockhopper penguin

• Published in: Marine Biology
• Main Authors: Delord, Karine, Cotté, Cédric, Terray, Pascal, Bost, Charles-André, Weimerskirch, Henri, Barbraud, Christophe
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: envir; geo; Indian; Amsterdam Island; Rockhopper penguin
• Online Access: https://doi.org/10.1007/s00227-021-03832-z; https://hal.archives-ouvertes.fr/hal-03138865

International audience Understanding the factors that drive the dynamics of populations of long‐lived species presents a unique challenge forconservation management. Here, we investigated long-term change in the body condition of adult northern rockhopperpenguins Eudyptes moseleyi at Amsterdam Island, southern Indian Ocean, which hosts 5–10% of the global population ofthis endangered species. Analysis of a long‐term dataset (1994–2016), concurrent to the population’s rapid decline, revealedno trend in adult northern rockhopper penguin body condition over time at the stages considered in this study, i.e. breedingand moulting. However, body condition varied between years and sexes and part of this variation was explained by environmentalfactors. Males were on average in better condition than females whatever the stage and individuals on averagewere in better condition during the moulting compared to the breeding period. The environmental conditions [sea surfacetemperature anomaly (SSTa), Subtropical Indian Ocean Dipole (SIOD) and Southern Annular Mode (SAM)] appeared toimpact non-linearly the body condition. Overall, females were in better condition for negative values of SAM, SIOD andSSTa. The body condition of males exhibited similar but less complex and more significant patterns, with decreasing bodycondition for increasing SAM, SIOD and SSTa. The absence of long-term trends in male and female body condition suggeststhat the very low reproductive output and declining population since 1997 is probably not the result of environmental conditionsduring pre-breeding and pre-moult and necessitates further research into possible drivers during the breeding season