Multi-state mark-recapture models as a novel approach to estimate factors affecting attendance patterns of lactating subantarctic fur seals from Marion Island

• Published in: Antarctic Science
• Main Authors: Nevoux, Marie, De Bruyn, P.J. Nico, Wege, Mia
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2015
• Subjects: Arctocephalus tropicalis; Detection probability; Pup sex; Seasonal effects; Transition probability; Antarctic Science; Marion Island
• Online Access: http://hdl.handle.net/2263/49101; https://doi.org/10.1017/S0954102014000716

Observer-based studies often underestimate key ecological parameters. Here a fresh approach was used to analyse six years (2006–11) of attendance cycles to estimate foraging trip lengths of a lactating flipper-tagged otariid: subantarctic fur seals at Marion Island. Multi-state mark-recapture models were used to calculate detection failures of females, correct estimates accordingly, and investigate the effects of year, season, pup sex and the presence of a telemetry device on attendance cycle parameters. There were no differences between corrected and uncorrected attendance data. This is attributed to the high capture probability across all seasons (range: 83–98%). This illustrates that observer-based studies are useful to augment telemetry studies. Only season and pup sex had a significant impact on female provisioning rates. In winter, foraging trip durations were longer (t-value = 25.22, P <0.0001) and attendance durations shorter (t-value = -2.15, P = 0.01) than during summer. Females with female pups spent a higher proportion of their time on land (χ2 = 6.6, P < 0.05). Male pups have higher growth demands and are larger which suggests they can deplete female milk-stores faster. Department of Science and Technology,through the National Research Foundation (NRF), in support of the Marion Island Marine Mammal Programme (MIMMP) of the MRI. http://journals.cambridge.org/action/displayJournal?jid=ANS 2015-12-31 hb2015