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.

No abstract

1982. Seaward movement of coho salmon (OnccprhyBzchus kisutch) fry in Carnation Creek, an unstable coastal stream in British Columbia. Can. J. Fish. Aquat. Sci. 39: 588 -593.The seaward movement of coho (Oncsrhyncba~,s ki,~ubch) fry was monitored over a 10-yr period as a part of a major watershed study. The time period over which downstream movement took place varied widely during different years of study. Coho fry moved seaward earlier, and terminated the main period of movement earlier, following winters in which stream temperatures were Riamer. It is presumed that they underwent more rapid development during winters in which stream temperatures were relatively high. Winter stream temperatures were primarily dependent on air temperatures. During seaward movement daily numbers fluctuated widely. Peaks of movement were coincident with or slightly before freshet peaks. In 94 of 122 cases (97%) the amumber sf fry moving seaward during the night of peak discharge, or during the night before, was higher than in any of the three preceding nights. Movement in these cases may kave been initiated by rainfall or falling water temperature or a combination of both. Aggressive behavior among coho fry is considered to be an underlying cause of seaward movement. In Carnation Creek, particularly in the early part of the period of seaward movement, the effects of such social behavior on movement patterns may be masked by the effect of freshets and related conditions. By autumn the number of fry remaining in the stream ranged from 9000 to 13000 over the 10-yr study. Much of the downward ad-iustment to this resident fry population size occurred after the most active period of seaward movement. . 1982. Seaward movement of coho salmon (Oncorhynchw kisufch) fry in Carnation Creek, an unstable coastal stream in British Columbia. Can. J. Fish. Aquat. Sci. 39: 588 -597.Une tranche de 1'Ctude d'un important bassin hydrsgraphique a comport6 la surveillance des dkplacements vers la rner d'alevins de saumon coho (Oncorhynchus kksurch) sur une pkriode de 10 ans. L'tpoque de la descente varie grandement d'une annCe a l'autre. Les alevins se dirigent vers la rner plus t8t et la principale pkriode de migration en aval se termine plus t6t apres des hivers sb la tempdrature de l'eau est plus klevee. On suppose que pendant ces hivers, les aIevins se dkveloppeant plus rapidement. Les tempkratures hivernales des cours d'eau dependent surtout des tempkratures de l'air. Le wombre des alevins accuse de fortes fluctuations quotidiennes lors de la migration vers la mer. Les maxima co'a'ncident avec ceux des cmes ou les prkcedent lkgerement. Bans 94 sur 122 cas (7'7 %), le nombre d'alevins se dkpla~ant vers la rner au COIU-s d'une nuit de d6bit maximal ou de Ia nult pr6ckdente est plus Clevk que celui sbserv-olt dans une des trois nuits prCcCdentes. II se p u t que, damas ces cas, la migration soit dkelenchee par la pluie ou un abaisseanent de la temperature de l'eau, ou une combjinaison des deux. On cmit que 1e comportement agressif des alevins de saumon...

1989. Stream temperatures and inter-annual variability in the emigration timing sf coho salmon (Onesrhyncdaus kisutch) smolts and .fry and churn salmon (0. keea) fry from Carnation Creek, British Columbia. Can. 8. Fish. Aquat. Sci. 46: 1396-1405 Variability in average stream temperatures between peak spawning and fry emergence accounted for 82 and 77% of the variance in the median emigration date sf fry of chum (Oncorhynchus keta) and coho salmon (0. kisutch), respectively, over a 9 to 10-yr period. The modeled relationships were indistinguishable from laboratory models that predicted time to rnaxirnyrn alevin wet weight. Variability in stream temperatures during the spring accounted for 60% sf the variability in the median date sf coko srnolt emigration. As stream temperatures increased, the predicted thermal surnrnati~ws required for emigration were nearly constant for coho salmon fry, increased moderately for churn salmon fry and increased strongly for coho salmon srncplts. The duration of the emigration period also differed between the groups: 50% of the churn salmon fry emigrated aver a I-wk period compared with a 2-to 3-wk p e r i d for coho salmon fry and smolts. We speculate that the emigration timingtemperature relationships and timing of adult spawning represent adaptations for synchronizing emigration with "windows sf opp~rtunity~' in the ocean sr stream. The windows are of different widths and levels of predictability for coho and churn salmon fry and coho salmon srnolts.La variabilite de !a temperature msyenne du courant entre la p6riode maximale de fraie et Bt6rnergenee des alevins cornptait respectivement pour 82 et 77 % de [a variance de la date de migration des alevins de saurnon k6ta (Oncsrhywchus keta) et de saurnsn coho (0. kisutchj au cows d'une periode de 9 2 10 ans. Les rapports mod6iis$s 6taient indistinguables des rnod6les de laboratsire qui pr6disaiene la perisde necessaire pour que les alevins atteignent leur poids frais maximal. La variabi tit6 de la temp6rature ddu courant au printemps cornptait pour 60 % de la: variabilite de la date mediane de migration des smolts de saurnon coho. A mesure qu'augmentait la temperature, Ees somrnations therrniques prevues pour la coho, augmentaient de f a p n mod6rc5e pour les alevins de saurnon keta et augmentaient forternent pour les smolts de saurnsn coho. La duree de migration differait 6galement dfun group A B'autre : 58 % des alevins de saurnon keta rnigrent sur une peride de 1 semaine comparativernent A une p5riode de 2 3 3 sem. pour les alevins et les smolts de saurnon coho. Nous forrnul~~ns lfhypsth&se que les rapports entre le moment de la migration et la temperature et J e moment du frai A /'Age adulte representent des adaptations & une migration synchronisee en fonction de (( fenetres specifiques )) dans Ifocean s u les cours d'eau. La largeur des fenetres varie de meme que le niveau de prevision pour les alevins des saurnons coho et k6ta et les smolts de saumon coho. 'Contribution No. 140 of the @mation Creek Watershed Project. 'Present ...

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.