Juvenile Chinook Salmon (Oncorhynchus tshawytscha) Utilization of Hawks Creek, a Small and Nonnatal Tributary of the Upper Fraser River

Abstract

Scrivener, J.C., T.G. Brown, and B.C. Andersen. 1994. Juvenile chinook salmon (Oncorhynchus bhawytscha) utilization of Hawks Creek, a small and nonnatal tributary s f the upper Fraser River. Can. J. Fish. Aquat. Sci. 51 : 1 139-1 146. Hawks Creek, a small tributary of the upper Fraser River where there is no record of spawning salmonids, was examined from May to November 1990 for the presence of juvenile salmonids. Age 0' wild chinook salmon (Oncorhynchus tshawytscha) appeared in May, increased to peak densities s f 0.76 fisham-' in late August, and were absent in November. Average residence time of marked chinook juveniles was 9 d. Duration of residency was size dependent, as small fish remained longer than large fish. Rainbow trout (Oncorkynchus mykiss) and mountain whitefish ( Prosspium williamsonij also had a short residency (mean = 21 d). We suggest that unsuitable rearing conditions (e.g., sediment load) in the mainstem Fraser River during the spring and summer favour the use of small, clear, and nonnatal tributaries by juvenile salmonids. Physical and biological explanations are proposed for their temporary use. These salmonid refuge habitats need to be protected. De mai A novembre 1990, wous avons surveilie le ruisseau Hawks, ern petit tributaire du Fraser dans sa partie amont, oO on ne rapporte pas la presence de salmonides gkniteurs, pour y trouver des salrnonid6s juveniles. Des quinnats suivages d'age 0' (Oncsrhynchus fshawytscka) sont apparus en mai, ont atteint une densit6 maximale de 8'76 poisson-rn-' 3 la fin aoQt et etaient repartis en novembre. En moyenne, Bes quinnats juveniles marquks restaient dans ce tributaire pendant 9 jours. La duke du skjour dependait de la taille en ce sens que les plus petits poissons y demeuraient plus longtemps que les gros. La truite arc-en-ciel (Qncorhynchers my&iss) et le menomini de montagnes (Prosopium williamsoni) sejournaient peu, eux aussi, dans ce cours d'eau (moyenne = 21 jours). Nous pensons que des conditions d'elevage defavorabfes (p. ex., charge en sediments) dans le Fraser-meme au printemps et 3 I'6t6 poussent les salmonides juv6niles 3 fr6quenter Bes petits tributaires limpides qui ne sont pas leur lieu d'origine. Nous proposons des explications d'ordre physique et biologique a B'emploi temporaire de ces tributaires. Ces habitats qui servent de refuge aux salmonid6s doivewt &re proteges.

Juvenile Chinook salmon (Oncorhynchus tshawytscha) growth in off-channel and main-channel habitats on the Sacramento River, CA using otolith increment widths

“…These levels of turbidity were observed in the main-channel during the study period in both 2001 and 2002. In addition to effecting growth, high turbidity may cause juvenile salmon to select less-turbid off-channel sites during high flows (Scrivener et al 1994). The inundation of seasonally dry areas habitats (including floodplains, off-channel ponds, and tributaries) increases the overall wetted area available for fish and other aquatic organisms and may increase prey availability (Sommer et al 2001).…”

Tributary connectivity, confluence aggradation and network biodiversity

“…This type of increased local heterogeneity at confluences has been associated with discontinuities in the longitudinal distribution and diversity of invertebrates Knispel and Castella, 2003), periphyton and fish (Kiffney et al 2006;Torgersen et al, 2008). In addition, the juxtaposition of contrasting physical conditions between the tributary, upstream and downstream links may offer unique opportunities for mobile taxa (Power and Dietrich, 2002), including for example, local (and therefore low-cost) access to contrasts in illumination, substrate stability, turbidity, predator avoidance and water temperature (Kupferberg, 1996;Scrivener et al, 1994;Fraser et al, 1995;Cairns et al, 2005;Katano et al, 2009;Taverny et al, 2012). There are other reasons why confluences are important for river biodiversity including: provision of nutrient or prey subsidies (Wipfli and Gregovitch, 2002;Fernandes et al, 2004;Wellard-Kelly, 2013); the presence of unique confluence-zone habitats (Nakamoto, 1994;Franks et al, 2002;Kreb and Budiono, 2005); the amplification of competition amongst species (Besemer et al, 2013); and bi-directional filtering that affects organism dispersal (e.g.…”

Investigations into the Early Life-history of Naturally Produced Spring Chinook Salmon and Summer Steelhead in the Grande Ronde River Basin, Annual Report 2001.

“…This early peak may indicate that larger individuals in the rearing population have a greater propensity to emigrate as early migrants or migrate sooner than smaller individuals during the early migration period. Larger individuals have been found to migrate sooner than smaller fish in natural populations of spring chinook salmon and coho salmon Oncorhynchus kisutch (Scrivener et al 1994;Irvine and Ward 1989). Similarly, larger hatchery chinook salmon have been found to migrate sooner than smaller individuals (Ewing et al 1984;Beckman et al 1998).…”