This report summarizes life history characteristics of winter and summer runs of wild and hatchery steelhead (since 1953) based on scale analysis. Where possible, annual growth rates and age structures were summarized for each stream and hatchery. To back-calculate lengths from scale measurements, the natural logarithms of scale radii vs. the natural logarithm of body length for fish >45 mm to adult size was used in the Fraser-Lee back-calculation procedure. Separate regression equations were calculated in systems with sufficient data and for wild and hatchery fish. Condition factors were highest for wild winter runs followed by hatchery winter runs, then wild summer runs. Wild winter run fish were mainly 2.2, most wild summer runs were 2.3 and 3.3 at spawning. Repeat spawning was higher among females than males. Mean back-calculated length at smolting for 6 individual river systems ranged from 173 to 185 mm. Mean back-calculated smolt lengths from systems where separate regressions were not available ranged
Hooton, R.S., Ward, B.R.; Lewynsky, V.A.; Lirette, M.G.; Facchin, A.R.. 1987. Age and Growth of Steelhead in Vancouver Island Populations. Ministry of Environment and Parks. Fisheries Technical Circular. FTC77
Topic: Fish and Fish Habitats
Keywords: steelhead, hatchery, growth, age, spawning, size, Vancouver Island
Scientific Name: Oncorhynchus mykiss
English Name: Rainbow Trout
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