7631

• UCREFRP Catalog Number: 7631
• Author: Byrne, A. and T. C. Bjornn.
• Title: Predicting the Effect of Supplementation with Hatchery Fish on a Native Steelhead Stock - a Modeling Approach.
• USFW Year: 1991.
• USFW - Doc Type: 91-26,
• Copyright Material: NO

w

3,200
2,600
2,400
2,000
1,600
jr 1,200
z a°°
400
Q
0
W 3,200
Q 2,800
Z 2,400
2,000
1,600
1,200
800
400
0
i/
- - - - - - - - - - - -

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GENERATION

- - - - - 0.5 M, 0% -----•---• 0.5 M, 200A
1.0 M, 0% ---------- 1.0 M, 20%
3.0 M, 0% .................... 3.0 M, 20%
No fry stocked
Fig. 1. The number of returning native spawners when 500,000 (0.5 M, 1,000,000 (1.0 M), and 3,000,000
(3.0 M hatchery fry were planted in the Lochsa River for the first 15 generations. The fitness of fiy with a
hatchery ancestry was 0.667 and the mating overlap rate was zero (0%) or 20%. The initial number of
native spawners was 250 (top) and 2,500 (bottom) fish.

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