The characteristics of a fattening period of farm juvenile of Coho (Silver) salmon Oncorhynchus kisutch (Walbaum) in the Udarnitsa River (Southeast Sakhalin Island)
2009
Frenkel, S.E., All-Russia Reseach and Development Inst. of Fishery and Oceanography, Moscow (Russian Federation)
The maximum concentrations of farm juvenile of Coho salmon are marked in the mouth of the Udarnitsa River and its tributary, the Fish-breeding Stream, where the Okhotskij Salmon Fish Farm (SFF) is located. In summer and autumn the young fishes of advanced ages (1 +, 2 +) can be found down the River, except for its foothill section. In June larger fishes (the average of 11,7-12,4 cm) fattened in the mouth section, the shallow (10,0-11,0 cm) -in the upstream. From the beginning of July in the Udarnitsa River and its tributaries the average dimensions of fishes did not exceed 10,8 cm. The feeding of yearlings and two-yearling of Coho salmon consisted of ground and aerial Invertebrates, and in the mouth section of the River - leeches and a farm chum salmon in the issue season. The average full-fed index in May - the beginning of October varied from 50 to 95o/ooo , but only in feeding season the index increased up to 114-179o/ooo. The average dimensions of the under-yearlings which got to a Stream during cleaning the sections, increased from 6,3 (in the middle of June) to 0.73 m (in the beginning of July). Ground and aerial Invertebrates, larvae and chrysalis of caddis flies and leeches were their basic nutrients. Average general indexes of stuffing the stomachs in the first and second half of June and in July accounted of 163,123 and 280o/ooo accordingly
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