ISSN 1063-0740, Russian Journal of Marine Biology, 2009, Vol. 35, No. 4, pp. 279–287. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © V.S. Labay, 2009, published in Biologiya Morya.
Usually the changes in lagoon communities of
Sakhalin Island show a long-term pattern, which is due
to the gradual isolation of lagoons from the sea [15, 16].
In early June 2006 the canal connecting the lagoonal
Izmenchivoe Lake with Mordvinova Bay of the Sea of
Okhotsk was ﬁlled with sand as a result of a storm. Ear-
lier, in 2004–2005, in the course of integrated hydrobi-
ological expeditions performed by Sakhalin Institute of
Scientiﬁc Fisheries and Oceanography (SakhNIRO) the
water biota of the lagoon water body, including the bot-
tom community, was studied and described . A
reinvestigation performed in June 2007 according the
Contract No. KhD 29/2007 allowed obtaining unique
data that demonstrated the quick response of the bottom
community of Izmenchivoe Lake to the termination of
water exchange with the sea.
MATERIAL AND METHODS
At the background stage the bottom samples were
collected in May 31–June 10, 2004 and in June 3–10,
2005. In June 2004 samples were collected at 22 sta-
tions (70 samples) and in June 2007 at 7 supplementary
stations (27) (Fig. 1). After the canal was obliterated, on
June 5–10, 2007 we performed resampling of the
benthos (22 stations, 70 samples) strictly following the
initial scheme of stations, schedule and methods of
sampling used in the course of the survey of 2004.
In depths down to 0.4 m deep the samples were col-
lected using a Levanidov’s bottom sampler (0.16 m
in greater depths the infauna was collected with a little
Van Veen sampler (0.0225 m
). The collected samples
were rinsed aboard the boat, ﬁxed with 4% neutralized
formalin, and labeled. The collected materials were
then treated by SakhNIRO scientists under laboratory
conditions. The organisms were identiﬁed as to their
species, dried with a piece of ﬁlter paper and weighed
with electronic scales that were accurate to 0.001 g.
The data on the surface water temperature in Mord-
vinova Bay for the period of observations were kindly
loaned to us by Zh.R. Tskhai, a scientist of SakhNIRO.
The Student’s t-test was used to reveal the signiﬁcance
of surface water temperature changes throughout the
To distinguish hydrobiont communities at stations
we used Chekanovsky’s index of percentage sim-
ilarity , calculated using the following equation:
is the proportion (%) of a certain species in the
total biomass at stations
respectively. The sam-
ples were considered as sampled from the same com-
munity if the value of the index exceeded 40%. Cluster-
ization of parent matrices was performed using the
method of unweighted pair-group averages .
Response of Macrozoobenthos of Lagoon Lake Izmenchivoye
(Sakhalin Island) to the Discontinuance of Water Exchange
with the Sea
V. S. Labay
Sakhalin Research Institute of Fisheries and Oceanography, Yuzhno-Sakhalinsk, 693016 Russia
Accepted January 29, 2009
—Hydrobiological surveys in lagoonal Izmenchivoye Lake (Sakhalin Island) were carried out in
2004, 2005, and 2007 in order to examine the main changes in the composition and structure of macrozoob-
enthos after the cessation of its communication with the sea. Changes in the hydrological regime of the lake led
to a signiﬁcant reduction in the species list, a decline in the diversity of benthic communities, as well as a two-
fold increase in the population density of constituent species. The characteristic communities of the seawater
cold spreading layer and tidal littoral communities disappeared after the water exchange with the sea ended.
The latter communities were replaced with a lacustrine exposed littoral community dominated by amphipods
and isopods. The previously shallow-water community dominated by the bivalve
the main benthic community. The number of warm-water elements increased markedly. Water temperature
proved to be the main factor affecting the composition and structure of benthos of Sakhalin lagoons at the initial
stages of evolution of macrobenthos.
lagoon lake, hydrobiological regime, benthos, community.