Comparative studies of salmonid rearing habitat within logged and unlogged reaches of two streams were conducted during 1972 to 1974 in the central interior of British Columbia, 80 km east of Prince George. Both streams were barren of fish until stocked with rainbow trout in 1972. In Centenial Creek, transport of sediment through reserve strips (from disturbed, sloping deposits of fine textured soils) reduced the quality of salmonid rearing habitat because concentrations of suspended sediment reached levels (mean concn 75 mg/L) where benthic insects decreased markedly. Interstices of rubble in pools and runs were also filled with sediment in lower Centenial Creek, reducing potential over-winter habitat of salmonids.
In a small tributary that was clearcut, but where soils were coarse and stabilized rapidly, assessment of rearing capability of trout habitat suggested: (a) little effect on invertebrate drift and on survival of planted trout in an upper reach, logged by felling and skidding away from the stream; and (b) reduced density of drifting invertebrates and decreased survival of trout fry in a lower reach that was associated with extensive in-stream falling and skidding one year earlier. Growth of underyearlings during summer to autumn, however, was significantly greater in both logged reaches; populations apparently benefitted in growth rate from moderate increases in water temperature which were not associated with chronic sedimentation or low dissolved oxygen.
Results indicate that forest harvest planning in the central interior should emphasize in priority: (a) intensive use of soils inventory for planning landings and skid trails, and particularly roads and streamside reserve or filter strips; (b) perscription of conventional erosion control techniques, especially vegetative stabilization of disturbed fine textured soils; and (c) perscription of appropriate streamside practices that necessiate falling and skidding away from stream bank zones.
Slaney, P. A., Halsey, T. G.; Smith, H. A.. 1977. Some Effects of Forest Harvesting on Salmonid Rearing Habitat in Two Streams in the Central Interior of British Columbia. B.C. Ministry of Recreation and Conservation. Fisheries Management Report. 71
Topic: Fish and Fish Habitats
Keywords: British Columbia, Prince George, BC Central Interior, Centenial Creek, Rosanne Creek, forest harvesting practices, forest harvesting effects, salmonid rearing habitat, Kokanee (sockeye salmon), Bull Trout (Dolly Varden char), cyprinids, cottids