Newly detected haul-out of Atlantic walruses (Odobenus rosmarus rosmarus) on Yamal Peninsula has become the biggest in the Kara Sea

Atlantic walruses (Odobenus rosmarus rosmarus) are still poorly studied in the easternmost part of their range, especially in the Kara Sea. Therefore, any new data from this region on the biology and ecology of the subspecies are highly important. In autumn 2019, the largest coastal assemblage of walruses ever found in the Kara Sea was observed on the northwestern coast of the Yamal Peninsula. This assemblage was surveyed using a drone-mounted digital camera (from 5 m in altitude) on 17 October 2019. The herd comprised 1062 (± 17 SE) walruses. Approximately one-sixth of the assemblage consisted of dependent calves (0–2 years old), one-sixth consisted of mature bulls, one-third consisted of independent immature animals, and one-third consisted of mature females and young (mature) males. A considerable but not estimated number of walruses was also observed in nearshore water. Satellite imagery and an opportunistic visit to the site revealed that walruses used this haul-out from mid-September until at least the end of October. Satellite tracking of two tagged walruses showed that animals stayed within 200 km of the coastline in shallow water (not deeper than 20–25 m) throughout their tracking periods (8 and 9 days). In addition to the main haul-out, three more sites on this part of the Yamal Peninsula coast were identified as areas where walruses came ashore. These new abundance and distribution data from the Kara Sea add significantly to our knowledge regarding Atlantic walruses in this region. Considering the rapid and large-scale industrial development in the region, proactive measures should be taken to protect key walrus habitats in the Yamal Peninsula area.