The population of Atlantic walruses (Odobenus rosmarus rosmarus) living on the Franz Josef Land archipelago remains one of the least studied. In the summer-autumn of 2020-2021, satellite transmitters were installed on 26 walruses on the islands of the archipelago and on Victoria Island to study their movements and assess the use of the water area. In addition, 65 macrobenthos samples were collected in the study region to assess the distribution of walrus food resources.
IEE RAS employees, together with colleagues from the Arctic Research Center, Lomonosov Moscow State University Marine Research Center, and the University of Edinburgh, estimated the speed of animal movements: on average, walruses covered a distance of 29 ± 13.5 km/day at an average speed of 1.2 ± 0.6 km/hour. The speed of movement and the distance traveled statistically differed among males, females and the young. Such differences were noted for the first time and are probably related to the fact that immature individuals have difficulty accessing convenient resting places and the most nutritious areas, and in search of both they have to cover large distances. This is also confirmed by the analysis of the depths of movement: younger walruses were more often recorded in waters with depths greater than 100 m.
The individuals tagged on Victoria Island remained in the vicinity of the island, and the walruses tagged on the Franz Josef Land archipelago actively moved between the islands, using the entire water area. In their movements, the animals used known rookeries, but the use of the entire water area of the archipelago by individual animals was shown for the first time. It was also shown for the first time that Victoria Island is so important for the movement of walruses that the animals did not move more than 60 km from it.
One walrus tagged on the Franz Josef Land archipelago moved to the Novaya Zemlya archipelago in 5 days at the end of November, which may indicate a connection between the FJL walruses and the Kara-Barents Sea walruses. Perhaps the transition was caused by ice, which began to cover FJL at that time.
The study area was characterized by a high average biomass of macrobenthos. The bivalve mollusc Hiatella arctica dominated the macrobenthos biomass and was probably the main food resource for walruses.
Peak biomass values were recorded at a depth of 62 m, but the highest density of stations with high biomass values was located at depths of 15-30 m.
The publication was prepared as part of the work on the topic “Study and monitoring of walrus and polar bear as indicators of the sustainable state of marine Arctic ecosystems” within the framework of the Biodiversity Conservation Program of PJSC NK Rosneft.
The work was published in the journal Marine Mammal Science (Q1, IF= 2.0): The movement patterns and foraging resources of Atlantic walruses (Odobenus rosmarus rosmarus) in Franz Josef Land archipelago and connectivity with the Kara-Barents Sea population.