Effects of Forest Harvesting on Spawning Gravel and Incubation Survival of Chum (Oncorhynchus keta) and Coho Salmon (O. kisutch) in Carnation Creek, British Columbia

Abstract

Following logging, pea gravel and sand (i.e. fines) in the stream bed of Carnation Creek, British Columbia increased 4.6 and 5.7%, respectively. The quantity of fines was greater in the bottom layer, while the frequency and magnitude of changes in composition were greater in the top layer of streambed cores. Changes in streambed fines depended on the timing and type of streamside logging and on the timing of large freshets. Accumulating fines appeared to originate from erosion of streambanks or from upstream storage areas and they were transported as bedload. Suspended sediment (11.4–44.5 t∙km−2∙yr−1) did not increase after road construction or logging. Deposition and scour rates of pea gravel and sand in the streambed were inversely related to particle size, and to their depth in the bed. Following logging, survival to emergence declined from 29.1 to 16.4% for coho salmon (Oncorhynchus kisutch) and from 22.2 to 11.5% for chum salmon (O. keta). Annual mean survival to emergence and size of fry of both species were positively related to two indices of substrate composition. Annual changes in substrate composition and peak flows explained 60 and 73% of the variability in survival to emergence for chum and coho salmon, respectively.

Coeur d'Alene Tribal Production Facility, Volume III of III, 2002-2003 Progress Report.

“…Previous studies have demonstrated that reduced emergence success from high sedimentation can result in low juvenile densities and low adult recruitment (Cederholm andReid 1987, Scrivener andBrownlee 1989). Of the 6 sites where high levels of small or coarse fines were recorded, only the sites located in the mainstem of Lake Creek showed supporting evidence for low recruitment.…”

Survie Embryonnaire Du Saumon Atlantique (Salmo Salar L.) Dans Un Cours D’eau Du Sud De Son Aire De Répartition, La Nivelle

“…La morphologie particulière de la frayère (une dépression suivie d'un dôme), qui favorise la pénétration de l'eau dans le substrat (VAUX, 1962), est progressivement nivelée par les crues, ce qui limite ce processus. De plus, les sédiments fins qui pénètrent dans le substrat à ces occasions réduisent la circulation interstitielle de l'eau et les apports d'oxygène en provenance de l'eau de surface (VAUX, 1962 ;BESCHTA et JACKSON, 1979 ;SCRIVENER et BROWNLEE, 1989).…”

An Alternative Approach to Monitoring Fish and Fish Habitat in the Inland Northwest, 1999 Annual Report.

“…Management actions however, can have multiple impacts. For example, timber harvest can increase peak streamflows, increasing the mortality of young fishes (Scrivener and Anderson 1984), and can also increase streambed sediment, decreasing salmonid spawning success (Scrivener and Brownlee 1989).…”