1063-0740/01/2704- $25.00 © 2001
Russian Journal of Marine Biology, Vol. 27, No. 4, 2001, pp. 238–244.
Original Russian Text Copyright © 2001 by Biologiya Morya, Makoedov, Korotaev, Korotaeva.
The Chukotka’s largest stock of chum salmon
spawns in rivers of the Anadyr Bay region (Anadyr,
Velikaya, and Kanchalan rivers with tributaries); up to
the beginning of the 1990s its many-year average
catches were about 3000 tons a year. The important role
Anadyr Bay chum salmon play in the economy and life of
the aboriginal peoples of Chukotka has long been the sub-
ject of studies [1, 11–13, 17, 21–23, 27, 30–32, 34– 40].
Chum salmon are mainly ﬁshed at the top of Anadyr
Bay, and all chum salmon going into the bay are named
Anadyr chum salmon. Spawners go from the bay for
breeding to the basins of the Velikaya, Anadyr, and
Kanchalan rivers that ﬂow into Lake Onemen at a rela-
tively small distance apart (Fig. 1). Almost 85% of
chum salmon migrate from Anadyr Bay  to the
Anadyr River, and then part of the spawners stray to
tributaries of the lower, middle, and upper reaches of
the river. The spawning grounds within the Anadyr
River (basin area 191000 km
) are located up to several
hundred kilometers apart, while the spawning grounds
of the Anadyr, Kanchalan, and Velikaya rivers are up to
1000 km apart. The greater portion of chum salmon of
the Anadyr River proper breed in the area upstream of
Markovo [13, 32].
Because of the complex topography of the spawning
grounds, views on the population organization of
Anadyr Bay chum salmon are fairly controversial.
Shtundyuk  suggested that a single panmictic pop-
ulation of chum salmon exists in the Anadyr River
basin. In his opinion, this is evidenced by unstable con-
ditions at the spawning grounds of the Anadyr River,
which lead to interannual variation of the location of
these areas, thus hindering the formation of a stable
The study of gene frequencies of some enzyme sys-
tems of chum salmon of the Anadyr River and its tribu-
taries (Belaya, Maina, Eropola) revealed a low level of
genetic differences among spawning aggregations of
selected rivers of this basin. However, there was a dif-
ferentiation in samples collected at different periods of
the same spawning run and in different years [11, 29].
The results of a genetic–biochemical study  showed
that chum salmon of the Kanchalan River differ statis-
tically signiﬁcantly from Anadyr River chum salmon.
Putivkin  believes that the population heteroge-
neity of Anadyr Bay chum salmon is indicated by the
presence of several peaks of their sex ratio, which may
correspond to migrations of spawners from different
rivers and tributaries.
Investigation of the population organization of
Anadyr Bay chum salmon is of much applied impor-
tance. If there is a division into subpopulations, ﬁshery
pressure on individual components of the stock must be
spread uniformly [2–4, 19, 20].
The most important characteristic of population as a
ﬁshing object is its abundance. Previous studies of the
population organization of chum salmon of the Anadyr
Bay region have not attempted to elucidate the relation-
ship between spatial–temporal differentiation and the
abundance level [11, 31, 38].
The aim of this paper, which is the ﬁrst stage of our
research, is to assess the temporal heterogeneity of
chum salmon spawners at different levels of population
abundance. Temporal heterogeneity means the variabil-
Features of Temporal Differentiation
of the Chum Salmon
of the Anadyr Bay
Region at Different Abundance Levels
A. N. Makoedov, Yu. A. Korotaev, and O. B. Korotaeva
Chukotka Division of the Paciﬁc Fisheries Research Center, Anadyr, 686710 Russia
Received November 23, 2000
—The temporal heterogeneity of chum salmon stock of the Anadyr Bay region was investigated on
the basis of a set of discrete external morphological features and ﬂuctuating asymmetry level of some meristic
structures. Differentiation of Anadyr Bay chum salmon during the spawning run was found to be associated
with the abundance level of spawning stock in a particular year. Sharply pronounced temporal heterogeneity,
based on the investigated characteristics, in the area near the river mouth can be considered as an indicator of
the subsequent deﬁciency of spawners on the spawning grounds of rivers in the Anadyr Bay region.
Keywords: Chum salmon, Anadyr Bay, spawners, temporal heterogeneity, external morphological features,
ﬂuctuating asymmetry, differentiation, abundance level, spawning run, spawning grounds