Phoque barbu

Population sizes and trends are unknown for Bearded Seals within the European marine assessment area (see Kovacs et al. 2021 for a summary). The species has never been surveyed in Svalbard or western Russian waters. In northeast Greenland some survey effort has been undertaken in the Northeast Water Polynya area (NEW) for marine mammals generally, with some few Bearded Seals sighting (eight in winter and 14 in summer) in quite vast areas (c. 9,000 and 30,000 km²), so a population estimate was not possible based on these data (NAMMCO 2023). The natural low density of Bearded Seals and the fact that they spend very little of their time hauled out outside the moulting season (5%; Hamilton et al. 2018) makes it very challenging to determine the abundance of this species. Additionally, numbers on the surface are heavily influenced by wind and temperature conditions as well as seasonal patterns (Hamilton et al. 2018, London et al. 2022; see Scherdin et al. 2022 for more details). However, their distinctive spring breeding calls are easily monitored using passive acoustic listening/recording networks and such data suggests that this species remains widespread in the Atlantic Arctic (Moore et al. 2012, Ahonen et al. 2017, Llobet et al. 2023).

In other parts of the world, Bearded Seal abundance has been estimated, though most reports note that there are many regional gaps and that the species is in fact data deficient. Additionally, many older estimates should be considered educated guesses as opposed to actual estimates. Heide-Jørgensen et al. (2013, 2016) produced estimates for Bearded Seals in the North Water Polynya in West Greenland of some 6,000 animals. This is likely an underestimate for this important hotspot, given that these authors applied a Ringed Seal haul-out correction factor of 41% and available data suggests that individual Bearded Seals spend much less time than this on the ice surface (Hamilton et al. 2018). Fuirst et al. (2023) provide a thorough review of Bearded Seal estimates in Canadian waters, concluding that data coverage is too fragmentary to provide a comprehensive abundance estimate or trend, but regional populations range from some hundreds to low thousands of animals.

Population estimation of Bearded Seals has received considerable effort in the Pacific Arctic. A comprehensive review by Cameron et al. (2010) concluded that combined estimates for all regions in the Pacific Arctic summed to some 250,000 animals. More recently, Ver Hoef et al. (2014) analysed line transect survey data from the Bering Sea collected in spring 2007 using a series of models and estimated there were 61,800 Bearded Seals (95% CI 34,900–171,600) in their study area. A lot of effort has gone into methods to extrapolate survey observations to abundance estimates in the broad Pacific region for ice-seals (Conn et al. 2014, 2015, 2016; McClintock et al. 2015, Sigler et al. 2015), but only estimates from Russian territories have been published to date (in the Russian scientific literature) from the large-scale survey efforts. These studies suggest 42,000 Bearded Seals occurred in the Russian parts of the Bering Sea and 14,590 (CV 31%) were in the Russian parts of the Chukchi and Eastern Siberian Sea (Chernook et al. 2018, 2019). Boveng (in NAMMCO 2023) suggested that the total population size for the Bering and Chukchi Sea was 500,000, but Conn and Trukhanova (2022) concluded that abundance estimates from the large-scale aerial surveys for Bearded Seals (and Ringed Seals) in particular should be interpreted with caution because of the lack of age-sex specific data for calculating correction factors; low area coverage (2%) and low numbers of sighting in vast areas are additional concerns. However, close-kin mark-recapture estimates for Bearded Seals in the Bering, Chukchi, and Beaufort seas (Quakenbush, in NAMMCO 2023, citing Taras et al. 2023) also produce a large population estimate number - 409,000 (CV = 0.35). This region of shallow seas is undoubtedly a stronghold for Bearded Seal (Citta et al. 2018). Crance et al. (2022) found a year-round presence of Bearded Seals based on acoustics, throughout the Alaskan Chukchi and northern Bering Sea.