Japanese-style and gravel-box incubation of chum salmon (Oncorhynchus keta) compared at the fry stage / by R.A. Bams.: Fs97-6/1330E-PDF

"Three successive broods of Big Qualicum River chum salmon (Oncorhynchus keta) were incubated and reared from fertilization to an early fry stage using two techniques: a Japanese-style hatchery technique (JSH), which uses ground water and keeper-channels, and a deep-substrate incubation technique (Box), which uses river water and a gravel medium. Both treatments were replicated each year. The combined effects of the higher temperatures and the lack of a deep gravel substrate resulted in time of development (to 50% emergence) being accelerated by 56 (+1) days in all JSH groups. At emergence, JSH fry were smaller and less advanced than the Box fry but survivals were the same. The JSH fry were ponded and fed Oregon moist pellets for the 8-wk time period created by the differences in techniques. This resulted in substantial size gain of these fry at the time of emergence of the Box fry. Their average fork lengths ranged from 54.5 to 60.4 mm (mean 57.5) vs. 35.8 to 36.9 mm (mean 36.4) in the Box fry; their mean wet weights ranged from 1503 to 2291 mg (mean 1955) vs. 400 to 433 mg (mean 412). Growth rates were calculated and all results are compared with other available sources"--Abstract, page iii.

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