ATLANTIC WALRUS MONITORING IN THE NENETSKY STRICT NATURE RESERVE
Data on the distribution dynamics of the Atlantic subspecies of the walrus and the status of its habitats on islands within the Nenetsky Strict Nature Reserve were compiled and analyzed. According to the results of monitoring, walrus abundance on coastal haul-outs on the reserved islands demonstrated an upward trend in the period from 1991 to 2015. It is possible that this trend ensued not from population growth, but from the increasing role of coasts because of a reduction in ice extent and ice cover duration in the region caused by climate change, as well as because anthropogenic activities are causing more and more nuisance in marine habitats. For more reliable estimates of trends in abundance of the walrus it is necessary to develop and improve approaches to the study of the age and sex structure of the species population. Analysis of samples of near-surface seawater and bottom sediments for the content of petroleum and polycyclic aromatic hydrocarbons, mineral forms of nutrients and heavy metals in the coastal zone of the protected islands in 2014 and 2015 did not reveal concentrations in excess of allowable levels for most pollutants. At the same time, there is evidence of high concentrations of polychlorinated biphenyls in a single sample of adipose tissue of walrus from the region. It is recommended to study samples of benthic organisms, on which this species preys, for the concentration of pollutants. Walruses use haul-outs on the coast of the protected islands from July to October, with the highest concentrations observed in September and October. In this regard, in order to avoid negative impact on marine animals, it is recommended to conduct geophysical surveys at the protected islands in the first half of the navigation season, i. e. from July to mid-August.