Abstract <p>This article reviews the known methods for counting the sea otter <i>Enhydra lutris</i> (Linnaeus, 1758) of the Commander Islands population that has been steadily declining for the past 15 years. The relationship between the total abundance and the abundance at the northwestern haul-out site on Bering Island is shown: the long-term trend in population size is accurately identified using one rather large model haul-out site as an example. The results of different methods for counting sea otters at the haul-out site are presented. The use of a thermal imaging camera has been found to increase the efficiency of drive counts at night, especially in snow-free weather, being independent of light conditions. It is shown that counts of body prints in the snow at the haul-out site can be an alternative to drive counts.</p>