Some features of the biology of the mud shrimp Upogebia issaeffi (Balls, 1913) (Decapoda: Upogebiidae) from the subtidal zone of Vostok Bay,Sea of Japan

The study of the biology of the mud shrimp Upogebia issaeffi (Balss, 1913) from the subtidal zone of the Vostok Bay (Peter the Great Bay, Sea of Japan) revealed that this species occurs at depth of 1–6 m on mixed grounds of boulders, gravel, pebbles, shells of dead clams, and silty sand. The average population density of U. issaeffi in the local aggregation on a bottom transect of 300 m length ranged from 0.2 ± 0.4 to 8.0 ± 3.0 ind./m², the biomass varied from 0.5 ± 1.1 to 78.7 ± 28.3 g/m², or about 2.7% of the total biomass of macrozoobenthos and 51.2% of the biomass of decapod crustaceans, which is characteristic of the habitats of the mud shrimp. The maximum depth of burrowing of U. issaeffi was 65 cm. The aggregation consisted of animals with body lengths of 44–88 mm. The lifespan of U. issaeffi was 2–3 years. An equilibrium ratio of males and females (1: 1.06) was observed in the population. There were egg clutches on pleopods of 81.7% of the females. The body size of the smallest females with eggs was 67 mm. The larger the females were, the more of them were ovigerous individuals. About 4% of individuals of U. issaeffi were infected with the parasitic isopod Orthione griffenis.