The population dynamics and growth of the mud shrimp Upogebia major (De Haan, 1841) (Crustacea: Decapoda) from Peter the Great Bay, Sea of Japan

The dynamics of the size-age composition and growth of the mud shrimp Upogebia major in the upper sublittoral area of Vostok Bay (Peter the Great Bay, the Sea of Japan) were investigated in 2015 and 2016. Ovigerous females were found in April and May after the disappearance of the sea ice cover. Egg laying occurs only once during the breeding season. Hatching of larvae is observed in May, while in July the bottom population is replenished by a cohort of fast-growing young individuals that reach a body length of 43-44 mm during the first season of growth. In the third year of life, the females lay eggs for the first time at a body length of more than 73 mm. The females and males grow at the same rate; their growth can be approximated by a Bertalanffy equation of the form L-t = 118.4 [1-e(-0.5627 (t + 0.5305))]. The mud shrimp population consisted of 1-4- and, possibly, 5-year-old individuals 9-117 (females) and 8-116 mm (males) in body length. The specific features of the breeding, growth, and reproduction of the local populations of U. major are indicative of good adaptation of this species to the environmental conditions in Peter the Great Bay, which contributes to sustaining the biodiversity of the coastal zone in the region.