Download SEASONAL VARIABILITY OF SEXES RATIO AND REPRODUCTIVE

UDC 551.468.3(262.5)
Seasonal Variability of Sexes Ratio and Reproductive Cycle in Idotea balthica basteri
(Crustacea, Isopoda) in the Periphytic Communities of the Odessa Bay of the Black Sea / A.
Yu. Varigin // Gidrobiol. Zhurn. – 2016. – Vol. 52, N 1. – P. 15–22.
The seasonal variability of the sex composition of the Idotea balthica basteri (Pallas,
1772) population in the periphytic community of the Odessa Bay, the Black Sea was studied.
The annual variability of males : females ratio was revealed. Annual dynamics of males, females
and immature specimens I. balthica basteri ratio is conditioned by peculiarities of reproductive
cycle of the species in periphytic community of the Odessa Bay. Females predominate over
males almost all year round, except late autumn, when specimens return to coastal zone after
summer migration into deeper water layers. It was noted that I. balthica basteri reproducts
continuously all year round, but the most intensively in April at water temperature 10oC.. Data
on fertility of this species in periphytic community of the Odessa Bay was determined. The
relationship of this parameter with length and weight was shown. Absolute fertility and number
of spawns per life cycle in this species in the Odessa bay are twice as less than nearby the
Crimean coast. The equations of dependence of wet and dry weights of males, egg-bearing and
not-egg-bearing females on their length was presented. The total number of egg-laying over the
whole life cycle was determined.
KEYWORDS: Idotea balthica basteri, sexual ratio, reproductive cycle, fertility, periphytic
community, the Odessa Bay.
1 figure, 3 tables, 13 references.