Freshwater biology of Thompson River steelhead (Salmo gairdneri) as determined by radio telemtry
Date
1986
Authors
McGregor, Ian Angus
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Abstract
Radio telemetry , in combination with an intensive angler survey, was used to determine biology of late summer run steelhead (Salmo gairdneri) in the Thompson River. Twenty- eight Thompson steelhead were radio tagged in the fall of 1977 near Spences Bridge and fifteen were monitored to the completion of spawning in the spring of 1978 .
The mainstem Thompson, (downstream of Kamloops Lake ) Bonaparte and Deadman Rivers and Nuaitch Creek, (a tributary of the Nicola River) were identified as spawning areas by radio telemetry techniques . The Nicola River and tributaries, downstream of Nicola Lake , were also verified as spawning grounds for Thompson River steelhead .
Three ran io tagged steelhead migrated into the Bonaparte River where they encountered an impassable 6 .1 metre falls approximately 2 km from the confluence . There appears to be an excellent opportunity to naturally enhance salmonid runs in the Bonaparte River by providing passage of fish over these falls . Approximately 120 k m of spawning and rearing habitat is available above this natural obstruction.
Biological information was collected from adult steelhead during the 1976 /77 Thompson Rive r sport fishery and by the operation of an enumeration fence on the Deadman River in 1984. Scale analysis indicated Thompson steelhead return most frequently at ages 5 and 6.
Juvenile Thompson steel head spent less time (2 years) in freshwater than other steelhead stocks in British Columbia and Alaska and about the same duration as other stocks from Northwestern United States. Ocean phase duration is about the same as most other stocks with minor exceptions.
Smolts lengths were back-calculated from adult scale using the Fraser-Lee proportional method. Back-calculations indicated Thompson fish smolt at a mean size similar to other streams reported in the literature. Adult Thompson steelhead appeared to return at greater average length, weight and fecundity than most other stocks of steelhead in North America.