Pink or humpbacked
salmon, Oncorchynchus gorbuscha
Smallest representative of Pacific salmons. Passing species.
Enters Primorye rivers all over the coastline from Peter the Great Bay
to the northernmost areas, where its more numerous range in the northern
Pacific is as wide as that of the keta, from the shores of Korea on the
coast of Asia to the coast of California in North America. In RussiaТs
polar region, is widespread till River Lena.
Its body is
well proportioned and covered with little scales. The sides and abdomen
are in the sea, and when the gorbuscha enters rivers they are of silvery
color; the back is dark. The sideline is distinguishable well. The tail
fin has large and small dark spots, and the back small spots. After entering
rivers and staying in fresh water, the gorbuscha acquires a wedding attire:
its body flattens and becomes brown, the head and fins become black, and
the jaws warp to develop big teeth. A hump grows on the backs of males;
hence the name of the species. The scale caves into the skin to fuse with
it. The body shape becomes ugly, not resembling the one at sea.
maximum length does not exceed 68 cm, and its mass 3 kg, though cases are
known of some specimens being as long as 76 cm and weighing from 5 to 7
kg having been landed. The sizes of gorbuscha caught at approaches to the
coasts of Primorye vary widely from 30 to 66 cm; however, specimens whose
size ranges from 42 to 59 cm and weighing from 1.2 to 2.3 kg prevail. The
males are as a rule larger than the females. Gorbuscha is a rapidly growing
species that matures in its second year.
gorbuscha school spends its sea life period in the southern and southwestern
areas of Japan Sea. There they intensely feed on large plankton crustaceans,
squids, and anchovy to start their northward spawning migration to the
rivers of Primorye and Sakhalin in April. By the end of May, gorbuscha
reaches the latitudes of northern Primorye, and in June migrates to the
coastal waters, to pre-estuary spaces of spawning rivers. In Primorye,
rivers start running in June to continue to run till the end of August.
chiefly along river main beds and partly along lower reaches of large tributaries.
The lower boundary of spawning grounds passes at 2-3 km from river estuaries,
and the upper boundary in relatively large rivers 15-30 km away. As a rule,
the spawning grounds are situated on shoals with clear water and on unsilty
soil consisting of gravel and pebbles with sand admixture. Spawning begins
in August to continue till mid-September. The female would lay row
in one, two or three nests to cover them with pebbles. This results in
an oval spawning mound 1.5-3.5 m long and up to 60 cm wide. The soil layer
over the roe is 30-35 cm thick. During several days lasting about one week,
the females would protect their roe to not allow other species to spawn
on the same site, and then, completely weakened, would be carried away
by currents to die. After spawning, the males would also die. The embryos
would peck from there in 90-120 days after fertilization (approximately
in the second half of December) to stay in their nests till spring, feeding
on yolk sac reserves. In late April, the larvae would start to emerge into
the water to be carried away by the river current.
into the sea, the young would for about one month stick to shallows near
start to actively feed on
small crustaceans. They would then leave for the open waters of Japan Sea
to return to their native rivers for reproduction after spending from twelve
to eighteen months in the sea. Significantly, the homing instinct in gorbuscha
is pronounced less distinctly than in other Pacific salmon. Gorbuscha is
the most numerous representative of Pacific salmon, ranking first among
them in fish harvests. The Primorye gorbuscha school, unlike those of Sakhalin
and Kamchatka, is relatively small and subject, like in other areas, to
significant fluctuations from year to year.