Abstracts of Fisheries Management Reports, Technical Circulars and Project Reports of the Fisheries Branch Daiva O. Zaldokas & Debra L. Aird B.C. Fisheries Branch, 2204 Main Mall, U.B.C., Vancouver, B.C. V6T 1Z4 Fisheries Technical Circular No. 91 1992 VANCOUVER ISLAND PROJECT REPORTS LIRETTE, M,G. 1988. Telemetric Studies of Summer and Winter Steelhead in the Stamp and Somass Rivers, 1984-85. Fish. Rep. No. VI 881:23p. The freshwater migration behaviour of summer- and winter-run steelhead (Salmo gairdneri) were studied on the Somass River system between August, 1984 and May, 1985. Radio telemetry techniques were employed to monitor instream movements of steelhead and to determine time and location of spawning. Between August 21, 1984 and March 19, 1985, 271 steelhead were captured by angling the Stamp and Somass Rivers. Fifty- nine fish were held for broodstock, thirty-three were radio tagged, one hundred and sixty five were anchor tagged, six (8%) summer-run and 8 (4%) winter-run steelhead died from angling injuries. Tagged fish were comprised of summer-(n = 70), early winter- (n = 94) and late winter-run (n = 34) steelhead. Thirty-two tagged steelhead (16.2%) were recovered at Robertson Creek Hatchery. Seventeen tagged fish were recaptured by sport anglers. Angling recaptures varied between summer (7.5%), early winter (10.8%) and late winter (3.4%) tag groups. Wild steelhead were recaptured at over two times the rate of hatchery produced fish. One of the ten steelhead radio tagged in August (10%), five of the seven tagged in October (71%), seven of the eleven tagged in December (64%), and five of the five radio tagged in January/March (100%) were monitored to their spawning location. The average migration rate varied between radio and anchor-tagged groups of summer- (0.24 and 0.77 km/week), early winter- (0.42 and 1.12 km/week) and late winter- (0.64 and 2.44 km/week, respectively), run steelhead. Summer- and winter-run hatchery produced steelhead utilized the smolt release site (7-9 kms) and Roberston Creek Hatchery 25-27 kms) for spawning. Wild winter-run steelhead utilized areas above and below Stamp River falls for spawning (9-11 and 19-21 kms). The spawning location of wild summer-run steelhead was not determined.