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If you have any questions on the information presented, or require additional report data or attachments, please contact the Report Contact
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The upper Sustut River steelhead population was
enumerated from August 3 to October 1, 1996, for the fifth consecutive year. From 1986 to 1996 the abundance of upper Sustut River steelhead
fluctuated little and ranged from a high of 823 in 1986 to a low of 476 in 1993.
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Author: Parken, C.K. K.L. Morten and D.Y. Atagi
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Old Reference Number: sk107
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Date Published: Jul 1997
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Report ID: 2602
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Audience: Government and Public
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The upper Sustut River steelhead population was
enumerated from August 3 to October 1, 1996, for the fifth consecutive year. One fence, approximately 500 m upstream of the confluence of the Sustut River with Moosevale Creek, was used for enumeration. Four hundred and sixty-six
steelhead passed through the fence between August 3 and September 30. An additional 49 steelhead were counted downstream of the fence to the Moosevale Creek confluence, but included fish that were previously counted as they migrated
upstream through the fence and were then able to migrate downstream over the fence during the freshet in late September. This estimate also included steelhead counted at the fence and released downstream. The fall escapement was above the estimated number of spawners required for maximum sustainable yield, but substantially below carrying capacity. The steelhead mortality rate due to handling at the fence was 2.8 percent. In 1996, 14 percent of steelhead had gillnet marks
and 11 percent had predator scars. Between August 4 and September 30, a total of 3,368 sockeye salmon, 33 coho salmon and 8 bull trout
were counted at the fence. The first steelhead arrived at the fence on August 17 and by September 7, 50 percent of steelhead had passed
the fence. Of the eight steelhead recaptured in 1996, six were repeat spawners and two were tagged earlier in 1996. At least 1.3 percent of the 1996 steelhead run were repeat spawners, as evidenced by Floy tags from previous years. In 1996, increases in steelhead migration did not coincide with changes in water temperature, but did coincide with an increase in river height. Male steelhead were significantly larger than female steelhead. About 10 to 30 sockeye salmon heads and 6 steelhead heads were in the Sustut River
between the Junction Pool and the fence, indicating low Native harvest. From 1986 to 1996 the abundance of upper Sustut River steelhead
fluctuated little and ranged from a high of 823 in 1986 to a low of 476 in 1993. The fall escapement of steelhead exceeded the minimum spawning requirements for conservation in all years examined, but were substantially below the estimated carrying capacity. From a review of all years of tagging data, tagged upper Sustut
River steelhead were estimated to migrate by Tyee between June 25 and August 10, whereas tagged lower Sustut River steelhead were estimated to migrate by Tyee between July 16 and September 7. The significantly different timing of tagged upper and lower Sustut River steelhead indicated two separate populations. The upper Sustut River population index was positively correlated and significantly related to the cumulative steelhead index at Tyee test fishery on August 10. The
fork lengths of 1996 male and female steelhead were significantly larger than the 1992 steelhead run, but similar to 1993, 1994 and 1995 steelhead. The mean fork lengths of male and female steelhead with gillnet marks were significantly different than male and female steelhead without gillnet marks, although the magnitude of differences
was small.
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Report Type
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Fish and Aquatic Habitat Information |
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Subject
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Fish Species - Steelhead - Oncorhynchus mykiss |
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Region - Skeena |
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Fish and Fish Habitat - Stock Assessment |
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Watershed Groups - 490 - Sustut River |
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