245 
Determination of population structure and stock 
composition of chum salmon ( Oncorhynchus keta) 
in Russia determined with microsatellites 
Nataly V. Varnavskaya 
Kamchatka Fishery and Oceanography Research Institute 
18 Naberezhnaya Street 
Petropavlovsk-Kamchatsky 683000, Russia 
Abstract — Variation at 14 microsat- 
ellite loci was examined in 34 chum 
salmon (Oncorhynchus keta) popula- 
tions from Russia and evaluated for 
its use in the determination of popu- 
lation structure and stock composi- 
tion in simulated mixed-stock fishery 
samples. The genetic differentiation 
index (F st ) over all populations and 
loci was 0.017, and individual locus 
values ranged from 0.003 to 0.054. 
Regional population structure was 
observed, and populations from Pri- 
morye, Sakhalin Island, and north- 
east Russia were the most distinct. 
Microsatellite variation provided 
evidence of a more fine-scale popu- 
lation structure than those that had 
previously been demonstrated with 
other genetic-based markers. Analy- 
sis of simulated mixed-stock samples 
indicated that accurate and precise 
regional estimates of stock composi- 
tion were produced when the micro- 
satellites were used to estimate stock 
compositions. Microsatellites can be 
used to determine stock composition 
in geographically separate Russian 
coastal chum salmon fisheries and 
provide a greater resolution of stock 
composition and population structure 
than that previously provided with 
other techniques. 
Manuscript submitted 18 December 2007. 
Manuscript accepted 25 February 2008. 
Fish. Bull. 106:233-256 (2008). 
The views and opinions expressed or 
implied in this article are those of the 
author and do not necessarily reflect 
the position of the National Marine 
Fisheries Service, NOAA. 
Terry D. Beacham (contact author) 
Email address: Beachamt@pac.dfo-mpo.gc.ca 
Department of Fisheries and Oceans 
Pacific Biological Station 
Nanaimo, British Columbia, Canada V9T 6N7 
Khai D. Le 
Michael H. Wetklo 
Department of Fisheries and Oceans 
Pacific Biological Station 
Nanaimo, British Columbia, Canada V9T 6N7 
In Asia, there are two distinct types 
of chum salmon ( Oncorhynchus 
keta Walbaum). The early-matur- 
ing or “summer” chum salmon gen- 
erally returns to spawn from June 
through August in streams border- 
ing Kamchatka, the Sea of Okhotsk, 
the east coast of Sakhalin Island, 
and the Amur River. Later-matur- 
ing or “autumn” chum salmon gener- 
ally return to spawn from September 
through November in streams in 
Japan, the southern Kuril Islands, 
the west coast of Sahkalin Island, 
and the Amur River (Sano, 1966). In 
general, summer chum salmon spawn 
in areas where egg incubation occurs 
in subsurface stream flow, whereas 
autumn chum salmon spawn in areas 
of groundwater upwelling (Volobuyev 
et al., 1990). In major river drain- 
ages, autumn chum salmon generally 
migrate further up the drainage to 
spawn than do summer chum salmon, 
and are larger, younger, and more 
fecund than the summer-run fish 
(Sano, 1966). 
Determination of the origin of 
salmon in mixed-stock fisheries is im- 
portant for effective management. For 
chum salmon in Asia, scale pattern 
variation has provided a technique 
for the determination of origin of in- 
dividuals to large geographic areas 
(Tanaka et al., 1969; Ishida et al., 
1989), and in some cases reportedly to 
a specific river drainage (Nikolayeva 
and Semenets, 1983). Trace elements 
in otoliths have also been reported 
to be effective for stock identification 
of Korean populations (Sohn et al., 
2005). Stock identification techniques 
based on scale pattern analysis have 
generally been replaced by applica- 
tions based on genetic variation, ow- 
ing to the increased resolution that is 
possible by applying genetic variation 
(see example outlined by Wilmot et al. 
[1998]). Analyses of genetic variation 
have been demonstrated to be effec- 
tive in determining salmonid popula- 
tion structure, as well as determin- 
ing origins of salmon in mixed-stock 
fisheries. For Russian chum salmon, 
analyses of allozyme variation have 
indicated differentiation among popu- 
lations on the east and west coasts 
of Kamchatka (Winans et al., 1994), 
and either marignal (Salmenkova et 
al., 2007) or some level of differentia- 
tion between populations on Sakhalin 
Island and populations on the main- 
land Russian coast (Efremov, 2001). 
Populations in the far northeastern 
