Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island

• DOI: 10.2981/wlb.00732
• Publication Date: 2020-10-08T10:22:21Z
• Authors: Rowan K. Jordaan; W. Chris Oosthuizen; Ryan R. Reisinger; P. J. Nico De Bruyn
• Keywords: Mark and recapture; Archipelago; Vital rates

Killer whales, Orcinus orca , are a cosmopolitan species with large ecological and demographic variation across populations. Population‐specific studies are, therefore, crucial in accurately assessing the status trends of local killer whale Such require long‐term datasets remain scarce, particularly Southern Ocean where detailed population specific have only been conducted at single archipelago – Îles Crozet. Here, we analysed 12 years capture–recapture data (comprising nearly 90 000 identification photographs taken from 2006 to 2018) whales subantarctic Marion Island (46°54′S, 37°45′E) estimate abundance, survival growth rate this population. Demographic parameters were estimated using multistate capture recapture models, Pradel Survival‐Lambda POPAN single‐state models implemented program MARK. Annual probability (0.98 [95% CI: 0.96–0.99]) was constant over time, no important differences between sexes age‐classes (calves, juveniles, adults) found. This suggests life expectancy approximately 48 years. Realised mean (λ) 1.012 (0.987–1.037) an size 54 (54–60) individuals calving 0.13 (0.06–0.20) calves born per year reproductive female. The reproduction rates similar those populations eastern North Pacific, Norway However, subtle present. These likely result resource abundances, historical impacts on social structure and/or stressors. Also, presence scale fisheries (legal illegal) area may provide opportunities for direct interactions fishing activities impacting rates.