Population dynamics of noble Astacus astacus, narrow-clawed Pontastacus leptodactylus and spiny-cheek Faxonius limosus crayfish in water bodies of Belarus

The growth rate of crayfish populations has been estimated – noble Astacus astacus, narrow-clawed Pontastacus leptodactylus, and spiny-cheek Faxoniuslimosus. The annual population growth rate of spiny-cheek crayfish was highest (3.02 year-1) and noble crayfish had lowest rate (1.44 year-1). Crayfish survival from larvae to sexual maturity was highest for the narrow-clawed crayfish (1.5 %) and lowest for the spiny-cheek crayfish (0.4 %). Pre-hatching fecundity of the spiny-cheek crayfish was 2.2 times higher than that for native species, but juvenile survival to sexual maturity was 3.6 times lower. The advantage that the spiny-cheek crayfish could have due to its high fecundity at the stage of growth and development of individuals completely disappears. The number of sexually mature females and their density ensure annual replenishment on a much larger scale. The main criterion of competitive advantages of the compared species is the rate of population increase. This indicator was maximal for Faxoniuslimosus.