New Insights on Polar Bear ( Ursus maritimus ) Diet from Faeces based on Next-Generation Sequencing Technologies

• Published in: ARCTIC
• Main Authors: Michaux, Johan, Dyck, Markus, Boag, Peter, Lougheed, Stephen, van Coeverden de Groot, Peter
• Other Authors: Animal, Santé, Territoires, Risques et Ecosystèmes (UMR ASTRE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Botanique, Université de Liège, Government of Nunavut, Queen's University Kingston, Canada, Fieldwork was supported by the Polar Continental Shelf Program, the Nunavut Wildlife Management Board, and Nunavut Tunngavik Inc. awards to the Gjoa Haven Hunters and Trappers Organization and P. van Coeverden de Groot, and a National Sciences and Engineering Research Council (NSERC) Northern Research Supplement to P. Boag. Laboratory costs were funded by the Nunavut General Monitoring Plan (P. van Coeverden de Groot, M. Dyck, J. Michaux, and P. Boag) with contributing funds from an NSERC Discovery Grant to P. Boag
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: polar bear; Ursus maritimus; diet; next generation sequencing; climate change; mitochondrial cytochrome b; ringed seal; [SDV]Life Sciences [q-bio]; [SDV.BA]Life Sciences [q-bio]/Animal biology; Arctic; Canada; Nunavut; Arctic Fox; bearded seal; Canis lupus; Churchill; Climate change; Erignathus barbatus; harbour seal; muskox; ovibos moschatus; Phoca vitulina; Pusa hispida; Sea ice; Vulpes lagopus
• Online Access: https://hal.inrae.fr/hal-03199309; https://doi.org/10.14430/arctic72239

International audience Practical tools to quantify range-wide dietary choices of the polar bear have not been well developed, thus impeding the monitoring of this species in a changing climate. Here we describe our steps toward non-invasive polar bear diet determination with the optimization of 454 pyrosequencing of a 136 base pair (bp) mitochondrial cytochrome b (cytb) fragment amplified from the extracts of captive and wild polar bear faeces. We first determine the efficacy, reliability, and accuracy of our method using five faecal samples from a captive polar bear fed a known diet at the Canadian Polar Bear Habitat in Cochrane, Ontario, Canada; 19 samples from three polar bears at the Metro Toronto Zoo, Toronto, Ontario, Canada; and seven samples from seven wild (unfed) polar bears from a holding facility in Churchill, Manitoba, Canada. We report 91% overall success in amplifying a 136 bp cytb amplicon from the faeces of polar bears. Our DNA analyses accurately recovered the vertebrate diet profiles of captive bears fed known diets. We then characterized multiyear vertebrate prey diet choices from free-ranging polar bears from the sea ice of the M’Clintock Channel polar bear management unit, Nunavut, Canada (n = 117 from an unknown number of bears). These data point to a diet unsurprisingly dominated by ringed seal (Pusa hispida) while including evidence of bearded seal (Erignathus barbatus), harbour seal (Phoca vitulina), muskox (Ovibos moschatus ssp.), Arctic fox (Vulpes lagopus), wolf (Canis lupus), Herring Gull (Larus argentatus), and Willow Ptarmigan (Lagopus lagopus). We found low levels of contamination (< 3% of sequences when present) and suggest specific process improvements to reduce contamination in range-wide studies. Together, these findings indicate that next-generation sequencing-based diet assessments show great promise in monitoring free-ranging polar bears in this time of climate change.