Migration patterns and phenotypic diversity of underyearlings of sockeye salmon Oncorhynchus nerka in the Ozernaya River basin (Kamchatka)
Journal of Ichthyology
0032-9452
Migration Patterns and Phenotypic Diversity of Underyearlings of Sockeye Salmon Oncorhynchus nerka in the Ozernaya River Basin (Kamchatka)
E. A. Kirillova 0
P. I. Kirillov 0
D. S. Pavlov 0
A. O. Zvezdin 0
0 Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences , Moscow , Russia
⎯ Migratory behavior, size composition, and feeding patterns of the underyearlings of sockeye salmon Oncorhynchus nerka from different intraspecific phenotypic groups in the Ozernaya River basin are studied. Complex organization of main phenotypic groups is demonstrated: several labile spatial-temporal groups are defined within them. The discovered phenotypic polymorphism is temporal and manifested by the sockeye salmon underyearlings only during the period in which they reach the main rearing grounds.
sockeye salmon Oncorhynchus nerka; underyearlings; distribution; downstream migration; phenotypic diversity; Ozernaya River; Lake Kurilskoye
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Sockeye salmon Oncorhynchus nerka is the only
species of Pacific salmon specialized on reproduction
in lake and river systems
(Quinn, 2005; Bugaev and
Kirichenko, 2008)
. The most abundant populations of
sockeye salmon inhabit lakes of the Asian and
American coasts of the Pacific Ocean. Lake Kurilskoye
(Ozernaya River Basin), located on the southern
Kamchatka Peninsula, is the spawning and rearing
reservoir for the largest population of sockeye salmon
in Asia (the so-called Ozernovskaya population).
The geomorphological features of lake and river
systems determine the wide variety of reproductive
conditions of the species. The sockeye salmon
spawning grounds are located both in the lakes themselves
and in the rivers that f low in and out of them. In the
Ozernaya River Basin, which includes Lake
Kurilskoye, the sockeye salmon spawning grounds are
represented by three types: limnetic (littoral) make up
71% of the spawning area; riverine (in lake tributaries
and the river f lowing from the lake), 26%; and spring
brooks, 3%
(Ostroumov, 1970)
. In the first summer of
life, juveniles from spawning grounds of all types move
to the pelagic zone of the lake to the rearing area
(Krokhin and Krogius, 1937; Smirnov, 1975; Bugaev,
1995)
.
After emergence from the ground, juveniles come
under inf luence of various conditions (presence and
direction of currents, temperature and feeding
conditions) depending on the location of the spawning
grounds in relation to the rearing reservoir. Therefore,
to reach the rearing area, juveniles undertake
migrations of varying direction, distance, and duration. For
the sockeye salmon underyearlings of the Ozernaya
River Basin, three types of migrations from the
spawning grounds are typical: downstream migration from
lake tributaries and partially in the Ozernaya River;
upstream from the riverine spawning areas of the
Ozernaya River; movement of juveniles from the
littoral of the lake to the pelagic zone
(Krokhin and
Krogius, 1937; Egorova, 1970; Bugaev et al., 2009; Kirillova,
etc., 2010; Kirillova and Pavlov, 2011)
.
The variety of migration types suggests a complex
of various adaptations (ethological, morphological,
and physiological) in the juveniles and the formation
of the corresponding phenotypic groups. In literature
sources, there is information on the particular features
of the behavior and orientation of sockeye salmon
underyearlings in the current and their physiological
status during the dispersion, obtained both as a result
of observations in field and laboratory experiments
(Byrne, 1968; Raleigh, 1971; Brannon, 1972; Brett
and Glass, 1973; Bodznick, 1978; Hensleigh and
Hendry, 1998; Pon et al, 2007; Pavlov et al., 2012,
2013; Zvezdin et al., 2015)
.
The school of juveniles from spawning grounds
located in different parts of the lake and river system in
one feeding reservoir requires a specific study. The
first steps in this direction should be descriptions of
the migratory behavior and phenotypic diversity of
juveniles (the progeny of different spawning groups of
sockeye salmon) during migrations to the feeding
reservoir, which was the goal of this study.
BERING SEA
SEA
OF OKHOTSK
2
3
1
4
Lake Kurilskoye
MATERIALS AND METHODS
Lake Kurilskoye (Ozernaya River Basin) is a large
waterbody on the southern Kamchatka Peninsula
(Fig. 1): the area of the water surface is 77.1 km2, the
volume is 15 km3, the average depth is 195 m, and the
maximum depth is 316 m. Four large rivers (the
Khakytsin, Etamynk, Vychenkiya, and Kirushutk), several
small rivers, and many large and small streams
(Zolotoi Klyuch and other nameless tributaries) empty into
the lake; the majority of the latter are temporary and
exist only in the period of snow melting. Sockeye
salmon uses approximately ten lake tributaries for
spawning. The Ozernaya River (length 48 km), which
f lows from Lake Kurilskoye, empties into the Sea of
Okhotsk. The sockeye salmon spawning grounds are
located in the upstream river, over 6 km from its (...truncated)