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Size distribution, age, and sex ratio were studied for a population of baikalian endemic gastropod Maackia herderiana living on shallow-water rocky platform in South Baikal Lake. Six size groups were recognized. The age was determined from the number of annual growth rings on the shell. Each of groups I-V contained snails of two ages corresponding most probably to different generations: spring and autumn. Snails of 4 to 8 years old were assigned to the group VI. The sex ratio in M. herderiana was generally close to 1:1. A tendency to deficiency of females in older snails was similar to that described earlier by Kozminsky [2003] for Bithynia tentaculata. It could be explained by a longer life span of males and higher reproductive expenses of females.

Размеры, возраст и половая структура Maackia herderiana (Gerstfeldt, 1859) (Gastropoda: Caenogastropoda: Baicaliidae) из Южного Байкала
Максимова Н.В.; Ситникова Т.Я.;