Population Studies

many sets of papers reviewing the age and sex composition of autumn concentrations of Pusa caspica in the marine delta of the Volga, and feeding characteristics of seal in the area including the volume of food consumption. New data on the effect of the most pathogenic parasites upon population dynamics in seals are given.

Relationship between the evolution of parasites and the host is considered. It confirms the existence of the northern and southern local groups of the Caspian seal. Materials are given for the first time on the accumulation of toxic organic chlorides in the organs and tissues of the seal which can serves as a pollution indicator of the sea area, and which effects the reproductive capacity of females. Seal stock condition and their optimum utilization is also being discussed.