ISSN 1063-0740, Russian Journal of Marine Biology, 2007, Vol. 33, No. 5, pp. 319–320. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © S.Yu. Gagaev, 2007, published in Biologiya Morya.
There is actually no data available on the distribu-
tion of bottom biocenoses in the Anadyr Estuary (Ber-
ing Sea). The only exception is some information on the
algae of this estuary gained from diving research in the
early 1970s during an expedition of the VNIRO (All-
Union Research Institute for Fisheries and Oceanogra-
phy) . In this regard, new data on the biocenoses of
Anadyr Estuary would be of much interest.
MATERIAL AND METHODS
The materials were collected in August–September
1995, using SCUBA (a standard frame 0.1 m
Petersen bottom sampler (with a grip area of 0.025 m
and bottom trawl (with cod end of 40 by 10 cm). The
samples were collected along a hydrobiological
transect crossing the Anadyr Estuary northward off
Zaseleniya Cape and southward of Aleksandr Cape.
Quantitative characteristics were obtained for two
frame samples taken in the lower intertidal area and
three bottom samples from 4–6 m deep. The samples
were washed on sieves with a minimum mesh size of
. The trawlings were done for 5–7 min during
a drift from aboard the river tow ship “TINRO” at 8 to
20 m deep.
To determine size–weight relationships, all speci-
mens of common species were measured . For these
species, linear measurements in relation to age were
approximated using a linear modiﬁcation of the Berta-
lanffy equation. Biocenoses were distinguished on the
basis of species dominating in terms of biomass. The
expenses of zoobenthos for energy metabolism were
calculated from the parabolic relationship of respiration
to mean individual weight and population density (the
coefﬁcients of the equations were published earlier).
The population production of certain species was calcu-
lated from K
following the well-known equation 
and by an integral method . Production of biocenosis
was estimated as the sum of the productions in all
trophic levels, less the assimilation of populations of
predatory and herbivorous animals.
RESULTS AND DISCUSSION
The bottom biocenoses of the Anadyr Estuary in the
area of Anadyr City are distributed in a belt-like fash-
ion, and their species diversity increases with depth.
This is due to hydrological regime and substrate type.
Two types of biocenoses were identiﬁed in the investi-
A seasonal biocenosis of ﬁlamentous algae
spp. is found on stones, pebbles, and sand in low
intertidal zone, from 0–0.2 m deep. In addition to the
algae, several species of amphipods, chieﬂy
and an aquatic sowbug
are typical inhabitants of desalinated waters, com-
monly occur here in summer. The inhabitants of this
biotope are exposed to sharp variations of environmen-
tal factors (salinity and temperature, which ﬂuctuates
from negative values to 17
C and above) and the abrasive
effects of ice. The population density and biomass in the
biocenosis are 140
respectively. The annual production of the biocenosis is
up to 101.5
. Modiﬁcations of a similar
community were encountered along the eastern coast of
Chaunskaya Inlet in the East Siberian Sea; however, their
annual production was merely 26
, which is
due to the harsher environmental conditions .
In greater depths, on dense, patchily distributed ﬁne
sand, sound sampling was not done; however, amphi-
pods, sowbugs, and polychaete worms evidently occur
Biocenoses of Anadyr Estuary (Bering Sea) and Conditions
of Their Existence
S. Yu. Gagaev
Zoological Institute, Russian Academy of Sciences, St.- Petersburg, 199034 Russia
Received May 17, 2007
—Some bottom biocenoses in the river mouth area of Anadyr Estuary are studied. Seasonal biocenosis
of ﬁlamentous algae
spp. occurs in the intertidal zone, biocenosis of the bivalve
is common at a depth of 4–8 m. Species diversity increases with depth. The distribution of biocenoses and pop-
ulation structure depend on the hydrological regime and substrate type in the surveyed area.
biocenosis, Anadyr Estuary, Bering Sea.