Biological Report 82(11.49)A p r i l 1988

TR EL-82-4

Species Profiles: Life Histories andEnvironmental Requirements of Coastal Fishesand Invertebrates (Pacific Southwest)

CHINOOK SALMON

Fish and Wildlife ServiceU.S. Department of the Interior

Coastal Ecology GroupWaterways Experiment StationU.S. Army Corps of Engineers

Biological Report 82(11.49)TR EL-84-4April 1986

Species Profiles: Life Histories and Environmental Requirementsof Coastal Fishes and Invertebrates (Pacific Southwest)

CHINOOK SALMON

Mark A. Allen and Thomas J. HasslerCalifornia Cooperative Fishery Research Unit

Humboldt State UniversityArcata, CA 95521

Project OfficerJohn Parsons

National Coastal Ecosystems TeamU.S. Fish and Wildlife Service

1010 Gause BoulevardSlidell, LA 70458

Performed ForCoastal Ecology Group

Waterways Experiment StationU.S. Army Corps of Engineers

Vicksburg, MS 39180

and

National Coastal Ecosystems TeamDivision of Biological Services

Research and DevelopmentFish and Wildlife Service

U.S. Department of the InteriorWashington, DC 20240

This series should be referenced as follows:

U.S. Fish and Wildlife Service. 1983-19 . Species profiles: life historiesand environmental requirements of coastal fishes and invertebrates. U.S. FishWildl. Serv. Biol. Rep. 82 (11). U.S. Army Corps of Engineers, TR EL-82-4.

This profile should be cited as follows:

Allen, M.A., and T.J. Hassler. 1986. Species profiles: life histories andenvironmental requirements of coastal fishes and invertebrates (Pacific Southwest)--chinook salmon. U.S. Fish Wildl. Serv. Biol. Rep. 82(11.49).U.S. Army Corps of Engineers, TR EL-82-4. 26 pp.

PREFACE

This species profile is one of a series on coastal aquatic organisms,principally fish, of sport, commercial, or ecological importance. The profilesare designed to provide coastal managers, engineers, and biologists with a briefcomprehensive sketch of the biological characteristics and environmentalrequirements of the species and to describe how populations of the species may beexpected to react to environmental changes caused by coastal development. Eachprofile has sections on taxonomy, life history, ecological role, environmentalrequirements, and economic importance, if applicable. A three-ring binder isused for this series so that new profiles can be added as they are prepared.This project is jointly planned and financed by the U.S. Army Corps of Engineersand the U.S. Fish and Wildlife Service.

Suggestions or questions regarding this report should be directed to one ofthe following addresses.

Information Transfer SpecialistNational Coastal Ecosystems TeamU.S. Fish and Wildlife ServiceNASA-Slide11 Computer Complex1010 Gause BoulevardSlidell, LA 70458

or

U.S. Army Engineer Waterways Experiment StationAttention: WESER-CPost Office Box 631Vicksburg, MS 39180

iii

CONVERSION TABLE

Metric to U.S. Customary

Multiply B y

millimeters (mm)centimeters (cm)meters (m)kilometers (km)

square meters (m2)square kilometers (km2)hectares (ha)

To Obtain

0.03937 inches0.3937 inches3.281 feet0.6214 miles

10.76 square feet0.3861 square miles2.471 acres

liters (1)cubic meters (m3)cubic meters

0.2642 gallons35.31 cubic feet0.0008110 acre-feet

milligrams (mg) 0.00003527grams (g) 0.03527kilograms (k

9) 2.205

metric tons t) 2205.0metric tons 1.102kilocalories (kcal) 3.968

ouncesouncespoundspoundsshort tonsBritish thermal units

Celsius degrees l.a("C) + 32 Fahrenheit degrees

U.S. Customary to Metric

inches 25.40inches 2.54feet (ft) 0.3048fathoms 1.829miles (mi) 1.609nautical miles (nni) 1.852

millimeterscentimetersmetersmeterskilometerskilometers

square feet (ft2)acressquare miles (mi2)

0.0929 square meters0.4047 hectares2.590 square kilometers

gallons (gal) 3.785cubic feet (ft3) 0.02831acre-feet 1233.0

literscubic meterscubic meters

ounces (oz)pounds (lb)short tons (ton)

28.350.45360.9072

British thermal units (Btu) 0.2520

Fahrenheit degrees 0.5556('F - 32)

gramskilogramsmetric tonskilocalories

Celsius degrees

iv

CONTENTS

Page

PREFACE ...................................................................CONVERSION TABLE ..........................................................ACKNOWLEDGMENTS ...........................................................

NOMENCLATURE/TAXONOMY/RANGE ...............................................MORPHOLOGY/IDENTIFICATION AIDS ............................................REASON FOR INCLUSION IN SERIES ............................................LIFE HISTORY ..............................................................

Upstream Migration ......................................................Spawning ................................................................Eggs and Alevins ........................................................Fry and Smolts ..........................................................Downstream Migration ....................................................Estuarine Residence .....................................................Oceanic Residence .......................................................

GROWTH ....................................................................THE FISHERY ...............................................................ECOLOGICAL ROLE ...........................................................

Competition .............................................................Predation ...............................................................Food ....................................................................

ENVIRONMENTAL REQUIREMENTS ................................................Temperature .............................................................Salinity ................................................................Dissolved Oxygen ........................................................Substrate ...............................................................Depth ...................................................................Water Movement ..........................................................Turbidity ...............................................................Heavy Metals ............................................................

LITERATURE CITED ..........................................................

iiiivvi

113334567789

1011111313131314141617171718

19

V

ACKNOWLEDGMENTS

We are grateful for reviews by Richard J. Hallock and Kenneth K. Hashagen,Jr., California Department of Fish and Game.

vi

Figure 1. Chinook salmon.

CHINOOK SALMON

NOMENCLATURE/TAXONOMY/RANGE

Scientific name . . . . . Oncorhynchustshawytscha (Walbaum) (Figure 1).

Preferred common name . . . . Chinooksalmon

Other common names . . . .. King, kingsalmon, tyee, quinnat, springsalmon.

Class . . i . . . . . . . OsteichthyesOrder . . . . . . . . . .SalmoniformesFamily . . . . . . . . . . .Salmonidae

Geographic range: Spawning popu-lations of chinook salmon in NorthAmerica are distributed from theSacramento-San Joaquin River systemin central California north to PointHope, Alaska. Asian populations aredistributed from Japan north to theAnadyr River, USSR. Introductionsof young chinook salmon haveestablished spawning populations andfisheries in rivers tributary toSouth Island, New Zealand, and the

U.S. Laurentian Great Lakes. Themajor rivers in California thatsupport spawning runs of chinooksalmon are shown in Figure 2.

MORPHOLOGY/IDENTIFICATION AIDS

The following descriptions weretaken from McConnell and Snyder(1972), Hart (1973), and Moyle (1976).Fin rays: Dorsal 10-14, anal 13-19,pelvic 10-11, and pectoral 14-19. Thecaudal fin is moderately forked;adipose is stout and prominent; afree-tipped flesh appendage insertsjust above the pelvic. Cycloidscales, 130-165 pored scales onlateral line, 131-158 in rows above.Number of branchiostegal rays eachside of jaw, 13-19; gill rakers roughand widely spaced, 6-10 on lower halfof first gill arch; pyloric caeca,120-185.

1

42O

Kilometers Bay

Northwest-----_

1 Terminal DamCoastal Distribution

36O P A C I F I C O C E A N

36O

Figure 2. The major rivers in the Pacific Southwest that supportspawning runs of chinook salmon.

2

The adult has prominent irregularblack spots on back, upper sides,dorsal fin, and both lobes of caudalfin. Spawning males developmoderately hooked jaws and dark oliveto red skin. Lower jaw gum-line issol id black. Juveniles are closest inappearance to coho salmon (0.kisutch), but are distinguished by-6to 12 parr marks that are wider thanthe interstices; the anal fin isunpigmented between rays and theanterior tip is not distinctlyelongated; the adipose is pigmentedon upper surface, clear below; and thepyloric caeca count is diagnostic(>120, but <90 in coho salmon.)

REASON FOR INCLUSION IN SERIES

The chinook salmon supportsvaluable commercial and sportfisheries in the Pacific Southwest.This species accounted for over 69% ofthe salmon caught along the Californiacoast from 1971 through 1983,according to the PacificManagement

FisheryCouncil (PFMC 1984).

Chinook fry and smolts spend a portionof their early life in estuaries wheregrowth is rapid.

LIFE HISTORY

Upstream Migration-

Chinook salmon spawning runs inthe Sacramento-San Joaquin Riversystem produce over 50% of the annualocean harvest of chinook salmon inCalifornia (PFMC 1984). Runs in theSacramento River above the Red BluffDiversion Dam are composed of fourpopulations, divided follows(1971-81 means): fall 54%: late fall14%, winter 21%, and spring 11%(Reavis 1983).

The separation of chinook salmonspawning populations is based on thetimes of the upstream migration ofadults, spawning, and the downstream

migration of juveniles (Figure 3).External physical appearance, time ofgonadal development, and location ofspawning grounds are additionalfactors. Chinook salmon runs in thefall and late fall spawn in themainstem or tributaries shortly afterthey reach their spawning grounds.Those in the winter and spring runsmay remain in deep pools near theirspawning grounds for as long as 5months before their eggs ripen andspawning1967).

begins (Hallock and Fry

Terminal dams in the Sacramento-San Joaquin River system (Figure 2),which lack fish-passage facilities,have altered the relative compositionof the four spawning populations ofchinook salmon. Until the construc-tion of Shasta Dam in 1942, the winterrun of chinook salmon spawned in upperSacramento River tributaries and wasbelieved to be of minor importance.After 1942, water released from thedam created favorable spawning tem-peratures in the mainstem SacramentoRiver for winter-run chinook salmonand their numbers increased (Slater1963). Spring-run chinook salmon,

= Lh

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .

z . . . .._.........._..

22h

> ‘_’ x02km

2 L -------*--. . . . . . . . . . ..m.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._..............

2: II-=ii_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

<lLmqgm Some yearitngs

,IIrlr’r”“““““T“ A M J J A S O N D J F M A M J J A S O N D

MONTH

- -dI0=A d u l t mlgratlon Juvenile Spawning

d o w n s t r e a m migration

Figure 3. Adult migration, spawning,and juvenile downstream migration ofchinook salmon in the Sacramento Riverat Red Bluff Diversion Dam, Califor-nia; circles indicate peak activity(Hallock 1983).

3

however, were unable to adapt to theloss of their headwater spawninggrounds and their numbers decreased.

The construction of Friant Damon the San Joaquin River in 1939blocked the spring-run of chinooksalmon from their spawning grounds andthey have all but disappeared (Hallocket al. 1970; California Department ofFish and Game 1971). Now (1971-84)only a fall-run population remains andaverages only 10% of the fall-run ofchinook salmon in the Sacramento River(Figure 4).

Spring-run chinook salmon alsoascend the Eel and Klamath Riversystems to spawn but have contributedless than 5% o f all chinook salmonproduced in California. Chinooksalmon spawning runs have decreased inall California rivers, especially inthe Sacramento and San Joaquin Rivers(Figure 4).

The release of gonadal or thy-roid hormones in adult salmon maystimulate upstream migration bymodifying fish behavior in responseto external variables that influencemigration (Hoar 1953). An increasein the volume of stream flow is the

Sacramento River system

San Joaquin River system

1952 5 4 56 58 600 0 2 64 6 6 68 70 72 7 4 7 6 7 0 SO 82Y E A R

Figure 4. The estimated number offall-run chinook salmon (may includesome spring-run fish) that returnedyearly to the Sacramento and SanJoaquin Rivers to spawn in 1953-83(data from Taylor 1974; Reavis 1983;PFMC 1984).

most frequently cited environmentalstimulus to upstream migration, butthis relation is most evident in smallrivers (Banks 1969). Changes inatmospheric pressure, water turbidity,water temperature, and dissolvedoxygen are also known to influenceupstream migration.

Low dissolved oxygen and highwater temperatures inhibited upstreammovement of fall-run chinook salmon inthe San Joaquin River (Hallock et al.1970). Most adult chinook salmonmigrate upstream during the day(Needham et al. 1940; Banks 1969).Fall-run chinook typically migrateupstream at a rate of 5 to 14.5 km/day(Gray and Haynes 1979; Heifetz 1982).

The homing of salmon to theirparent stream after enteringfreshwater is well documented and isattributable to olfactory cues thatare specific for each location and are"learned" by the juvenile salmonshortly before they migrate to the sea(Hasler and Wisby 1951; Hasler andScholz 1983). Genetic history mayalso influence homing success (Bams1976).

Salmon do not usually feed afterentering freshwater and severe atrophyof the digestive system sets in beforespawning begins.

Spawning

The female chinook salmon usu-ally chooses a nesting site in graveldeposits at the lower lip of a pooljust above a riffle (Burner 1951;Briggs 1953). The female makes a redd(an area containing several individualnests) by turning on her side andrepeatedly flexing her body and tailto force gravel and fine sediment intothe water column; these sediments aredeposited a short distance downstream.The completed nest forms an oval de-pression with a mound of gravellocated immediately downstream.

4

During spawning, a dominant malesalmon accompanies the female andaggressively chases away other malesattempting to enter the redd area.The eggs and sperm are released intothe nest by the female and malesimultaneously. Usually one or moremales will position themselvesalongside the female opposite thedominant male and release sperm. Bythe end of the spawning, as many as 10to 12 male salmon may have attemptedto spawn with a single female (Briggs1953; Vronskiy 1972).

After the eggs are released, thefemale usually moves just upstream andrepeats the nest building and thespawning act. The fertilized eggs areburied 20 to 60 cm below the gravelsurface with the excavation materialfrom the new nest (Briggs 1953;Vronskiy 1972). The female willrepeat the process several timesbefore spawning is completed. Eachcompleted redd may contain severalnests; the overall size of the redd isdirectly related to the size of fishand inversely related to the size ofthe substrate particles, watervelocity, and density of spawners(Burner 1951; Vronskiy 1972). Femalechinook salmon sometimes dig falseredds (but do not deposit eggs there)before and after they build true redds(Briggs 1953).

Each female may spawn over aperiod of 5 to 14 days. Unlikefemales of other salmon species,female chinook salmon may defend theredd from intruding females for 5 to9 days after spawning (Briggs 1953;Vronskiy 1972).

After spawning, the salmondeteriorate rapidly, exhibiting largeopen wounds and heavy fungalinfection. Life expectancy afterspawning is 2 to 4 weeks (Briggs1953).

Eggs and Alevins

Fecundity variesofgreatly amongchinook salmon differentpopulations. For example, fecundityof fall-run chinook salmon averages3,634 eggs per female in the KlamathRiver but 7,295 eggs in SacramentoRiver fish. Difference in female sizealone cannot account for the variationin fecundity (Healey and Heard 1984).

Chinook salmon eggs are large:6.3 to 7.9 mm in diameter (Rounsefell1957) and 0.35 to 0.40 grams in weight(Leitritz and Lewis 1980).

The length of time reauired forhatching is inversely related to water‘temperature. Chinook salmon eggs havebeen successfully incubated andhatched at water temperatures of 4' to16' C; however, lower temperatures canbe tolerated in the later stages ofembryonic development (Combs andBurrows 1957; Combs 1965; Piper et al.1982).

Chinook salmon eggs areparticularly vulnerable to shockinjury. Injury can result from gravelmovement caused by bottom scouring,mechanical impaction, or superimposedspawning activity. Other causes ofegg mortality are low dissolvedoxygen, high concentrations of toxicchemicals, excessively high watertemperatures, infestations with fungior oligochaetes, predation by insectsor fish, and heavy sedimentation.Under poor conditions the mortality ofeggs may be as high as 95% (Wales andcoots 1954; Gangmark and Bakkala1960). Under ideal conditions themortality of the eggs may be as low as10% (Briggs 1953).

After hatching, alevins (yolk-sac larvae) remain in the gravelinterstices for a month or longer,during which time they exhibit thefollowing three major distributionalphases: a deeper submergence, aresting period, and an upwardemergence (Dill 1969). Salmonid

5

alevins are negatively phototactic andpositively geotactic and thigmotactic;these characteristics serve toencourage further submergence into thegravel and prevent premature emergence(Godin 1981). After deeper submer-gence, alevins remain relativelyinactive unless forced to disperse inresponse to excessive levels of carbondioxide or metabolic waste (Dill1969), or to avoid desiccation duringlow flow (Fast et al. 1981).

As the yolk sac is absorbed,alevins develop positive rheotacticand phototactic responses and begin anupward migration in the gravel (Dill1969). Intra-gravel movement ofalevins is governed by gravel size,interstitial spacing, rate of waterflow, dissolved gases, and watertemperature (Dill 1969; Godin 1981).

F r y and Smolts

Chinook salmon fry usuallyemerge from the gravel at night,probably as an antipredation measure(Barns 1969), and spend 1 to 18 monthsin freshwater. After emerging, mostchinook salmon fry immediatelydisperse downstream, possibly becauseof their new nondemersal habits andloss of visual contact with the streamsubstrate (Reimers 1973). Diurnaldispersion has been observed duringincreases in water turbidity andtemperature (Rutter 1904; Thomas1975). After emergence, the frydevelop neutral buoyancy, beginexogenous feeding, and develop socialbehavior (Barns 1969).

Chinook salmon fry in streamschange habitats as they grow older.Lister and Genoe (1970) generalizedchanges in order as follows: "initialhiding, possibly in the gravel;association with bank cover;appearance along open shorelines; andfinally, movement into higher velocitylocations along the stream margin orfarther out from shore." After theinitial hiding period, chinook salmonfry seek fine substrates and low water

velocities, progressively moving intodeeper, faster, and rockier habitats(Lister and Genoe 1970; Everest andChapman 1972). Overwintering spring-run chinook juveniles hide under largerocks and debris, a habitat shiftapparently triggered by low watertemperature (Chapman and Bjornn 1969).

As the fry begin to smoltl, theybecome silvery and slimmer and changetheir behavior; their territorialinstincts break down, and they usuallyemigrate in schools downstream to theocean.

The osmoregulatory changes thatallow tolerance of saltwater aresomewhat more complex in chinooksalmon than in coho salmon or steel-head trout (Salmo girdneri) (NationalMarine Fishery Service 1979). Zaugg1981). Unlike the fry of othersalmonids, those of chinook salmontolerate high levels of serumchlorides and are able to rapidlyacclimate to high salinities. As thefry age in freshwater, their toleranceto salinity gradually increases, andsome enter estuaries without firstdeveloping the morphological char-acteristics of a smolt (Hoar 1976).The degree of salinity tolerancedepends somewhat on prior acclimation,but fish size and growth rate havebeen identified in several studies asfactors affecting salinity tolerance.The saltwater tolerance of larger fishof a given age is known to exceed thatof smaller ones. Ewing et al. (1980),who monitored gill (Na+-K+) - ATPaseactivity as an indicator of seawaterreadiness, found activity to be loweramong s-lower-growing fish; faster-growing fish had either a more fullyfunctional osmoregulatory system or

1/Smolt is a silvery juvenile, tolerantof seawater, migrating toward theocean; fry may live in estuaries withmoderate salinities, but generally donot enter the ocean. A parr is apre-smolt stage with vertical bars(parr marks) on the sides.

6

.

one that was capable ofhigher

fasteracclimation to salinities(Wagner et al. 1969). Most investi-gators agree that the parr-smolttransformation involves an endogenousrhythm affected by fish size andgrowth rate and environmental cuesthat include temperature, photoperiod,and lunar cycle (Ewing et al. 1979;Grau 1981).

Downstream Migration .

Juvenile chinook salmon form twomajor groups (Gilbert 1913): thosethat migrate to the ocean early intheir first year of life (ocean-type)and those that overwinter in fresh-water before entering the ocean(stream-type). Fall-run chinook sal-mon are typically ocean-type andemigrate downstream to estuaries asfry shortly after they emerge or assmolts (Reimers 1973; Kjelson et al.1982). Juvenile chinook salmon of thespring-run characteristically arestream-type and emigrate as yearlingsin early spring (Schaffter 1980).Winter-run chinook salmon fry emergein the summer and emigrate duringfall, when they are 4 to 7 months old(Slater 1963). The periods of peakabundance of migrating juvenile chi-nook salmon in the Sacramento Riverare shown in Figure 3.

Chinook salmon juveniles usuallyemigrate in the upper 2 m of water indaylight, but swim deeper and disperseafter dark (CDFG 1975; Schaffter1980). The larger migrants tend toconcentrate in midstream where currentvelocities are greatest (Schaffter1980). As spring progresses, thevertical distribution of emigrants isincreased as they disperse and inhabitdeeper water (Wickmire and Stevens1971). Increases in streamflow andturbidity also have been observed toincrease the vertical and horizontaldistribution of migrants (Hallock andVan Woert 1959). Fry migrate slowerthan smolts, a characteristic attrib-utable to their preference of slowervelocity streambank areas or their

orientation; they face upstream,whereas smolts swim downstream(Schaffter 1980). Estimates of themigration rates of fry and smoltsaverage 1.6 km/day in the mainstream(Rutter 1904; Wickmire and Stevens1971; Kjelson et al. 1982). The timeof year, water temperature, stream-flow, and fish size are all factorsinfluencing the time and speed ofdownstream migration.

Estuarine Residence

Several early life history pat-terns of fall-run chinook salmon in acoastal Oregon river were reported byReimers (1973). Most fish emigratedinto the estuary in the spring as fry2 to 3 months old (50-69 mm long).Some fry entered the ocean in mid-summer, but others remained in theestuary an additional 2 to 4 monthsand entered the ocean in the fall (90to 119 mm long). From scale analysisof returning adults, Reimers (1973)concluded that the survival of fishthat remained in the estuary untilfall was greater than that of migrantsthat left the estuary in mid-summer.

Other juvenile chinook salmonmigration patterns, according toReimers (1973), include fish that godirectly into the ocean from fresh-water. Newly emerged fry may directlyenter the ocean; juveniles (70-85 mmlong) sometimes pass directly into thesea during fall freshets; and year-lings (100-130 mm long) may enter inthe spring.

Two principal movements ofjuvenile fall-run chinook salmon intothe Sacramento-San Joaquin Estuary(the Delta and Suisun, San Pablo, andSan Francisco Bays) have beenidentified (Kjelson et al. 1982). Fry(40-50 mm long) began entering theestuary in January and peaked in abun-dance in February and March; moststayed in the upper estuary's fresh-water channels (the Delta). A lateremigration of chinook smolts (80-90 mmlong) occurred from April to June; the

7

fish moved quickly through the Deltaand Suisun and San Pablo Bays.Chinook salmon smolts typically useestuaries only as migrationalcorridors to the ocean (Reimers 1973;Kjelson et al. 1982; Simenstad 1983),whereas fry remain in the estuaryuntil they become larger and environ-mental conditions stimulate them tomove into the ocean.

Estimates of chinook fry resi-dence time in northwestern U.S. andCanadian estuaries ranged from 10 daysto 2 months (Shepard 1981), Probablefactors that affected their length ofstay in estuaries were fish size,population density, prey abundance,habitat suitability, freshwater inflow(particularly abrupt increases), andwater temperature (Reimers 1973;Shepard 1981; Kjelson et al. 1982;Simenstad 1983).

Chinook salmon fry (30-50 mmlong) in estuaries characteristicallyfeed in schools in littoral or shallowsublittoral habitats such as salt-marshes, mudflats, and other inter-tidal areas. The feeding habits ofchinook salmon fry are regulatedlargely by the tidal cycle. For exam-ple, during flood tide, fry move fromsmall tidal channels into near-shoremarshes (Healey 1980, 1982). Noctur-nal onshore movements for feeding havealso been described for chinook salmonfry (Myers 1980; Cannon 1982). Largerfry and smolts congregate in surfacewaters of main and subsidiary channelsand move into shallow sublittoralzones to feed. Occasionally theyenter blind tidal channels, but theirstay appears to be transitory (Shepard1981; Simenstad 1983). The composi-tion of the substrate in estuariesinhabited by salmon is commonly mud,silt, and sand, and less frequently,coarser materials (Forsberg et al.1977; Healey 1980).

The distribution of chinooksalmon fry in the Sacramento-SanJoaquin Estuary seemed to be regulatedby freshwater inflow during the

downstream migration (Kjelson andRaquel 1981). In years of highfreshwater inflow, the fry inhabitedboth upper freshwater channels (theDelta) and the brackish waters ofSuisun Bay and San Pablo Bay. Inyears of low flow, most of the frywere restricted to the upper Delta.Spring discharge also affects survivalof fry in estuaries. High freshwaterinflow may reduce the mortality ofchinook salmon fry and smolts caused by high water temperatures, waterdiversion, and predation.

Sand sills frequently form atthe mouths of small coastal streams innorthern California; these cause lowertidal movement and salinities thanthose found in larger open estuaries.In such a stream, further emigrationis prevented by the sill and thegrowth and mortality of juveniles areaffected by the size of the estuaryand the population density of chinookpnd their predators (Reimers 1973).A strong relation between chinooksalmon abundance and availability ofsuitable habitat suggests thatestuarine land "reclamation" maysubstantially reduce the biologicalcarrying capacity of the estuary (Levyand Northcote 1982). Also, landmanagement practices (levees, streamchanneling and breaking sand sills)that reduce estuarine trapping ofincoming allochthonous materials mayreduce the detritus-based food webbelieved to be necessary to maintainan abundance of juvenile salmon(Sibert et al. 1978; Healey 1982).

Oceanic Residence

Upon entering the ocean, most ofthe chinook salmon smolts from theSacramento-San Joaquin Estuary migratenorthward, but a spring fishery forchinook salmon south of San FranciscoBay at Monterey is evidence that thereis some southward migration (Snyder1931). The extent of northwardmovement fluctuates considerably,depending on ocean environmentalconditions, food availability, and

8

race. For example, in a mark andrecovery study, over 50% of the 1949year-class of fall-run chinook salmonfrom the Sacramento River were caughtnorth of the Oregon border, but in afollowing study 90% were caught southof there (Jensen 1971). Analyses ofPacific coast catch data (sport andcommercial) suggest that fall-runchinook salmon spend most, if not all,of their oceanic life near shore,relatively close to their home river.Spring-run chinook salmon often leavenearshore waters in their first yearof life and seek out more northerlyhigh seas areas (Hartt 1980; Healey1983).

Male and female chinook salmonusually spawn when they are 3 to 4years old. Two-year-old male spawners(commonly called "jacks") usually makeup 10% to 25% of the spawning run inCalifornia waters. Yearling malechinook salmon may mature before theyemigrate to the ocean (Rutter 1904;Rich 1920).

Factors that account for thereturn of adult salmonids to theirnatal streams are among the mostperplexing and least understood facetsof salmon biology. The consensus ofsalmon biologists is that high seasnavigation is innately controlled, andthat the role of extrinsic environ-mental factors increases in importanceas the salmon approach their homeestuary (Brannon 1981). Orientationin marine waters is believed toinvolve magnetic and celestial infor-mation, interpreted by the innatelatitudinal and calendar senses of thefishes (Brannon 1981; Quinn 1981).The length of day, rate of change ofday length, sun position, and lightpolarization are suggested cues.Nearshore migration may be enhanced byonshore winds that concentrate riverwater close to shore where olfactorycues further guide the salmon (Banks1969 ) .

GROWTH

Chinook salmon fry newly emergedfrom the redd are 35 to 44 mm long andweigh as much as 0.5 g (Rich 1920).Fry grew 0.26 to 0.40 mm/day (mean0.33 mm/day) in the upper SacramentoRiver, but during the same period,0.40 to 0.69 mm/day (mean =0.53 mm/day) in the estuary (Kjelsonet al. 1982). Growth rates generallyincrease in estuaries (Rich 1920;Reimers 1973). In more northernestuaries, growth ranged from 0.37 to1.32 mm/day (Shepard 1981). The rateof growth of chinook salmon furtheraccelerates when they enter the ocean.Fall-run chinook salmon smolts average8 cm total length (TL) when they leavethe Sacramento-San Joaquin Estuary andare as long as 30 cm by the end oftheir first year (Jensen 1971). Theaverage lengths of chinook salmon ofdifferent ages are shown in Table 1.

The average weights of salmonare greatest just before they migrateinto the river to spawn. They lose15% to 20% of their body weight duringupstream migration in large riversystems and an additional 10% to 15%during spawning (Rutter 1904).

Table 1. Mean total length (cm) and(in parentheses) percent compositionat each age of fall-run chinook salmonin the California commercial trollfishery, 1970-72 (from Denega 1973).

Age in yearsaYear 1 2 3 4 5

1970 34.0 45.7 68.6 83.8 99.9(32) (50) (17) (1)

1971 32.3 48.3 68.6 83.8 99.1(11) (60) (28) (1)

1972 - 43.2 68.6 81.3 96.5(21) (46) (32) (1)

'Lengths at age 1 were derived fromback calculation of scale.

THE FISHERY

The California commercial salmonfishery began along the SacramentoRiver in the mid-1800's. By 1881, 20canneries were processing over 10million pounds of chinook salmon fromthe Sacramento and San Joaquin Rivers.Two years later the fishery collapsed,presumably as a result of over-fishing and the loss of spawninghabitat from gold mining operations(Frey 1971; Jensen 1971). Gill netswere the most efficient means ofcatching salmon in the rivers, but ascatches declined in the late 1800's,some fishermen began trolling in off-shore waters. The California oceantroll fishery began near Monterey inthe 1880's and near Eureka andCrescent City in 1916 (Frey 1971).Chinook salmon caught in the oceanconstituted an increasing proportionof the commercial salmon catch becausethe major northern California riverswere closed to commercial salmonfishing from 1919 to 1933. Thecommercial salmon fisheries in theSacramento and San Joaquin Riversclosed in 1957. Annual chinook salmoncatches in California were highest in1918-19 and 1945-46 (over 13 millionpounds each year); record low landingsof less than 4 million pounds werereported for 1938-39, 1941, 1958 and1983. A summary of the annualCalifornia ocean sport and commercialtroll catches for selected years from1940 to 1983 is shown in Table 2.

All of the commercial salmon nowlanded in California waters arecaught by ocean trolling. Annually,an average of 4,800 salmon trollingboats expended 75,000 fishing daysfrom 1978 to 1983 (PFMC 1984). Sport-fishirg in the ocean has flourishedsince World War II and now contributesabout 21% of the California catch. Theocean sport fishery in Californiasupported an average of 193,000 anglertrips annually between 1971 and 1983(PFMC 1984).

Table 2. The number of chinook salmonin the sport fishery and the weightand value (all in thousands) ofchinook salmon in the commercialfisheries of California, 1940-83(data from National Marine FisheriesService 1940-75 and Pacific FisheryManagement Council 1984).

Sport fishery CommercialYear Numbers Pounds Dollars

1940 7a 5,156a 4111945 -- 7,912 1,4461950 56a1955 12ga

5,861 1,5729,317 3,266

1960 38a 5,996 3,2421965 60 7,397 4,1321970 148 5,266 4,4211975 104 5,781 6,1231980 86 5,907 13,1491983 62 2,308 4,609

'May include some coho salmon.

The Sacramento River and severalother northern coastal rivers inCalifornia support a substantial sportfishery for chinook salmon. From 1977to 1981, the average sport catch offall-run chinook salmon in theSacramento River was 1.8% of thetotal estimated run (Hoopaugh andKnutson 1979; Knutson 1980; Reavis1981a, 1981b, 1983). The sport catchof the remaining three stocks averaged1.8% of the late fall run, 1.7% of thewinter run, and 2.5% of the springrun. The salmon sport fishery in theKlamath River is estimated to composeup to 13% of the total chinook salmonrun and 7% of the total ocean sportand commercial catches of KlamathRiver fish (U.S. Fish and WildlifeService 1980, 1981, 1982, 1983, 1984).

The economic value of thePacific coast salmon fishery is ofgreat importance, ranking second inquantity and value in the entire 1983

10

U.S. marine catch (NMFS 1984). Theestimated value of California'scommercial chinook salmon fishery isshown in Table 2. The dollar value ofcommercial salmon depends on fish sizeand dockside ex-vessel price (Wahle etal. 1974). In 1983, ex-vessel pricesper pound ranged from $1.40 for smallsalmon less than 8 lb to $2.25 forfish larger than 12 lb (PFMC1984). The exact value of the oceansport salmon fishery is difficult toascertain, but an estimate of the neteconomic sport value of a chinooksalmon is $63.00 per fish. Chinooksalmon caught in rivers are estimatedto be worth $28.00 per fish (Mathewsand Brown 1970).

According to Wright (1981), thesalmon fishery needs to be regulatedfor optimum yield. He suggested thatoptimum yield may be reached by usingarea and season closures, minimum sizelimits, and gear restrictions. A moredirect method would be through theestablishment of limited entry orcatch quotas. Catch quotas ha v e beeninstituted in Oregon and Washington,and recently the California legisla-ture has joined Oregon and Washingtonin an attempt to limit the entry ofnew fishing boats into the existingfleet (PFMC 1984).

The magnitude of the chinooksalmon fishery has probablycontributed to the decline inabundance of the species. Ricker(1980, 1981) attributed the apparentdecrease in size and .age at maturityof chinook salmon stocks to the huge

.I salmon catch in the commercial trollfishery along the Pacific coast.Since the 1920's, the average weightof troll-caught chinook has decreasedsignificantly (some 2.5 kg in BritishColumbia waters from 1951 to 19751,and mean age at maturity for returningadults has decreased from 4 years to 3years. Ricker (1980) stated thattrends in ocean temperatures are notknown to be responsible for the ageand size decreases, but offers several

&other possible explanations:

11

1. The increased intensity of thetroll fishery has resulted inmore salmon being caught early inthe season and at a smaller size.

2. The ocean catch has been so largethat fewer salmon survive toolder ages and young fish make upa bulk of the catch (i.e., the"fishing-up effect").

3. The excessive removal of late-maturing salmon favors reproduc-tion of smaller, early-maturingfish.

The increased proportion of youngerfish in the spawning population hadbeen recognized earlier by Warner etal. (1961) for the Sacramento Riverand by Junge and Phinney (1963) forthe Columbia River.

Current California stocks ofchinook salmon are heavilysupplemented by hatchery fish that arereleased as fry or fingerlings (largefry to yearlings). Now being evalu-ated are the survival of hatchery-reared salmon and their contributionto the offshore fishery, returns tothe hatchery in relation to fish sizeat the time of release and thedistance from the point of release tothe ocean (Sholes and Hallock 1979;Kjelson et al. 1982). Production ofchinook salmon (State and Federalhatcheries) in California from 1971 to1981 is shown in Table 3.

ECOLOGICAL ROLE

Competition

Competition for spawning gravelsbetween chinook salmon and otheranadromous species is limited becauseof the chinook salmon's preference forspawning grounds in mainstem or largetributary streams and their earlyperiod of upstream migration andspawning. Downstream disperson ofnewly emerged Salmonid fry is adensity adjustment mechanism and may

Tabie 3. The numbers (thousands) andweight (thousands of pounds) ofjuvenile fall-run chinook salmonraised in State and Federal hatcheriesand released in California rivers from1971 to 1981 (data from CaliforniaDepartment of Fish and Game 1972-84and U.S. Fish and Wildlife Service1970-81).

State FederalYear Number Weight Number Weight

1971 37,845 413 8,186 1181972 28,793 446 12,360 1151973 23,384 452 10,971 1141974 15,115 371 12,518 1131975 27,039 443 7,205 271976 24,947 456 8,544 1041977 24,723 535 10,129 1161978 14,598 335 8,719 841979 16,187 555 7,411” 117a1980 20,133 677 16,951 2291981 34,850 650 16,060 138

a/ Includes some winter-run chinooksalmon.

result in cohabitation of chinooksalmon fry with juvenile steelheadtrout or coho salmon (Reimers 1973).Juvenile chinook salmon, like otherstream-dwelling salmonids, areterritorial, and competition for foodand space may result when they live inthe same waters with other salmonids.Fry of chinook salmon and coho salmonselect similar habitat, and cohosalmon are the more aggressive of thetwo species (Lister and Genoe 1970;Stein et al. 1972). The aggressionand territoriality of salmon fryappear to be influenced by currentvelocity, and are subdued in largepools and estuaries where schoolingis common (Reimers 1968). Intra-specific dominance is largely governedby fish size (Chapman 1962; Reimers1968).

The early downstream migrationof ocean-type chinook salmon fry

reduces contact with other species,but large introductions of hatchery-reared coho salmon may encouragepremature emigration of chinook salmonfry from freshwater into estuarine oroceanic waters and could reduce growthand survival of the chinook salmonmigrants (Stein et al. 1972). Myers(1980) reported a large degree offeeding overlap in estuaries betweenwild chinook juveniles and hatchery-released coho salmon and hypothesizeda high potential for competition.Stream-type chinook salmon live infreshwater for up to a year andfrequently occur with juvenilesteelhead trout. The selection ofdifferent habitats by the two speciesreduces competition for-space or food(Everest and Chapman 1972).

Upon entering the estuary,chinook salmon fry and smolts areconfronted with a sizable assemblageof potential competitors. Highpopulation densities of chinook salmonwithin estuaries increase intra-specific competition and may result inreduced summer growth and early oceanentry (Reimers 1973). Shepherd (1981)reported that fishes in estuariesknown to eat the same food as thatpreferred by chinook salmon are coho

to-San Joaquin Delta are juvenile

The greatest competitors ofchinook salmon in the ocean areprobably other Pacific salmon,particularly during peak abundance innearshore waters. Evidence of marine

12

density-dependent survival was notedby Peterman (1978) for northernPacific salmon stocks, but the oceanproper probably does not seriouslylimit salmon production (Walters etal. 1978). Analysis of food resourcesof the northern Pacific Ocean suggeststhat the supply of food for salmon isnonlimiting (Rothschild 1972).

Predation- -

Predation on salmon eggs usuallyis not a major cause of mortalitybecause the eggs are in the substrate.Predation on chinook salmon fry may behigh when they begin their downstreammigration. When salmon are concen-trated above or below dams or waterdiversion structures, some are easyprey to piscivorous birds such asbelted kingfishers (Ceryle alcyon)herons (Ardeidae), and mergansers(MergusS p p . ) , a n d larger salmonids,sculpins, Sacramento squawfish, andstriped bass (Morone saxatilis).Hatchery-released fingerling chinooksalmon and steelhead trout inSacramento River tributaries preyheavily on the smaller wild chinooksalmon fry (Sholes and Hallock 1979;Menchen 1981).

Predation by larger salmonids onchinook salmon fry and smolts may besubstantial in estuaries. Coho salmonsmolts are known to be highlypiscivorous during outmigration(Parker 1968), and predation by cohosalmon and other predators maysignificantly reduce survival ofhatchery-released salmon fry or smolts(Peterman and Gatto 1978). Otherestuarine predators include mergan-sers, cormorants (Phalacrocorax spp.),grebes (Podicipedidae), loons (Gaviaspp.), and ospreys (Pandionhaliaetus).

The extent of high seaspredation is unknown, but loss ofsalmon to northern fur seals(Callorhinus spp.) may range from 2million to 60 million salmon annually(Peterman 1978). The salmon shark

(Lamna ditropis) is another high-seas- -predator. Nearshore predators arecormorants, ospreys, sea lions(Eumetopias jubatus a n d Zalophuscalifornianus), harbor seals (Phoca- -vitulina), blue sharks (Prionaceqlauca), and lampreys (

Food

Chinook salmon tend to be moreopportunistic feeders than othersalmonids (Healey 1982). Fry instreams feed extensively on driftinsects (Rutter 1904), but zooplanktonare more heavily eaten in main riversystems and estuaries. Adult andjuvenile dipteran insects andcrustacean zooplankters -- especiallyCladocera and Copepoda -- are princi-pal food items of chinook fry in theSacramento River and the Sacramento-San Joaquin Estuary (Figure 5).Smolts feed on gammarid amphipods andlarval fish in brackish waters; largerand older smolts select largercrustaceans (Corophium and Neomysis)and fish as food (Cannon 1982). Theshift from shallow epibenthic prey tolarger, often pelagic species reflectsthe movement of juveniles from shallowlittoral habitats into deeper riverand tidal channels as they increase insize. Food consumed by marinedwelling juveniles consists primarilyof fish, crustaceans, and insects(Snyder 1924). Marine prey of adultchinook salmon are pelagic crustaceanssuch as krill (euphausiids), larvalcrabs, and fish (Figure 5).

ENVIRONMENTAL REQUIREMENTS

Temperature

Chinook salmon are coldwaterfish but they are more tolerant ofhigher water temperatures than otherPacific salmon (Brett 1952). Optimum,tolerable, and lethal water tempera-tures for different life stages ofchinook salmon are given in Table 4.Excessively abrupt water temperaturechanges may kill fish even within

13

American R. n =245(25-104mm)%Number (Barnhart and Giebink 1983)

Socromento -San Joaquin n=540 (< 70mm) %Number

(Kjelson, et al 1982)

CA Coast n= 1004 (343-1041mm)%Volume (Merkel 1957)

Figure 5. Stomach contents ofchinook salmon of differentlengths (in parentheses) andhabitats.

tolerated ranges. In the Delta, watertemperatures that exceed 23 C arelethal to most chinook smolts (Kjelsonet al. 1982).

Salinity

Among the Pacific salmons, juve-nile chinook salmon are most tolerantof changing salinities. Shortly afterhatching, the alevins tolerate moder-ate salinities (15 ppt), and at 100days of aqe and at a mean length of65 mm, they tolerate full-strengthseawater (Wagner et al. 1969). Sali-nity tolerance can be broadened byacclimation and is increased by thesize of the fish and rate of growth.Despite a high tolerance for highsalinities, studies in the Sacramento-San Joaquin Estuary and in southernCanadian estuaries suggested an appar-ent preference of low salinity waterby chinook salmon fry (Healey 1982;Kjelson et al. 1982). The salinityrequirements of juvenile chinook sal-mon are listed in Table 4. Adultsalmon tolerate rapid salinitychanges.

Dissolved Oxyqen

The dissolved oxygen (DO)requirements of chinook salmon embryosare unclear, but Alderdice et al.(1958) observed an increase in oxygendemand by chum salmon embryos as theyneared hatching. The effects of DOconcentrations below the saturationlevel on salmonids include delayed orpremature hatching (depending on thetiming of low DO in the eggdeve lbpment process); abnormal embryodevelopment; reduced size and strengthat hatching; reduced growth, feeding,and swimming ability; and increasedsusceptability to disease, predation,and toxic contaminants (Orsi 1967;Davis 1975). The DO requirements ofchinook salmon may change at variouslife stages (Table 4).

14

Table 4. Temperature, salinity,life stages of chinook salmon.

and dissolved oxygen requirements for several

Environmental Limitsfactor Life stage Optimal Tolerance Lethal Comments

:verature Adultupstreammigration

Spawning

Eggincubation

Juvenilerearing

Salinity(ppt)

Juvenile >15frearing

At 10 days post-hatch

Fall-run chinookSpring-run chinook

5.6-13.gb

5.8-14.2' < 0.6' Eggs survive nearfreezing afterinitial develop-ment to 128 ~~11stage at 5*C.

12-13e < 0.8e>25.1e

Acclimated at 10°CAcclimated at 24°C

>30f At yolk-sac ab-sorption (withacclimation) orat 100 days posthatch (withoutacclimation)

Dissolvedoxygen(mg/l)

Adultupstreammigration

>5.0b

Egg Saturationincubation

< 1.6g As percent satur-ation decreases,growth decreasesand abnormalitiesand mortalityincrease.

Juvenilerearing

>4.5h

>3.0h

Avoidance at 16-25OC.

Avoidance at 8-18'C.

aBell (1973).bReiser and Bjornn (1979).$Jombs and Burrows (1957).Piper et al. (1982).

efBrett (1952).Wagner et al. (i969).

gSilver et al. (1963).hWhitmore et al. (1960).

15

Substrate

Substrate requirements arefairly rigid for successful spawningand egg incubation. Chinook salmonspawn over a substrate ofunconsolidated materials of theappropriate size and adequateintragravel water flow, with properstream depth, current velocity, andbottom contour. The requirements forspawning and rearing of chinook salmonare described in Table 5. Chinooksalmon fry tend to prefer softsubstrates, possibly because of thepreferred low water velocities there,

but fry also inhabit areas of gravel,cobble, or bedrock in either streamsor estuaries (Everest and Chapman1972; Healey 1980). Juvenile spring-run salmon that overwinter in streamsare known to seek coarse substrates(cobble or boulder) for protectionagainst heavy winter and spring flows(Chapman and Bjornn 1969).

The greatest threat to thesubstrate quality is the accumulationof fine sediments on spawning gravelsand food-producing areas (Cordone and

Excessive sedimentationKelley 1961).clogs gravel interstices and reduces

Table 5. Habitat requirements of several life stagesI of chinook salmon.

Environmental Limitsfactor Life stage Optimal Tolerance Comments

Substrate size(cm)

Depth (t&

Watervelocity(m/s)

Spawninga

Juvenilerearingb

Adult upstreammigration

Spawning

Juvenilerearing

Adult upstreammigration

SpawningC

Juvenilerearing

1.3-10.2

silt silt-rubble

> 0.24

> 0.24

0.3-1.22

0.3-0.91

0.06-0.24

5 2.4’

5 6.1d

80% 1.3-5.1 cm,20%>5.1 cm

Sustained currentmaximum

Obstacle currentmaximum

90%-95% confidenceinterval

aBell (1973).bEverest and Chapman (1972).

'Thompson (1972).dWeaver (1963).

16

intragravel water flow, which isessential for the transport of oxygento, and metabolic wastes from, incu-bating egg surfaces. Heavy sedimen-tation may also trap alevins in thegravel, causing suffocation or star-vation. Sedimentation of rocky sub-strates also reduces the availablehabitat for food organisms and reducesfish escape cover.

Minimum depths are necessary toassure successful upstream migrationof adult salmon. During low flow,riffles may be too shallow for adultpassage. Thompson (1972) developedmethods by which critical areas areidentified and adequate passage flowsare estimated. Depth is important inspawning site selection because itaffects the hydraulic "head " andintragravel flow. Chinook salmon arereported to spawn at depths up to 10 min large rivers (Chapman 19431, butgenerally favor depths less than 3 m.Depth criteria for migrating andspawning chinook are listed inTable 5. Depth preference of stream-dwelling juvenile chinook salmon isabout 1 m and may be influenced bywater velocity, instream cover, fishsize, and the abundance of predatorsand competitors. Chinook salmon fryand smolts in estuaries favor surfacewaters in shallow flats or deepwaterchannels.

Water Movement

Adequate current velocities arerequired to assist the female in nestexcavation and for intra-gravel flow.Gangmark and Bakkala (1960) foundsignificant increases in mortality ofchinook salmon eggs when intragravelflow rates dropped below 60 cm/h.Juvenile chinook salmon in streams andestuaries select low velocityhabitats, but in streams the fry willseek faster waters as they grow largerand most select locations adjacent tohigher velocities where prey abundance

is greater (Everest and Chapman 1972).Current velocity preferences forspawners and juveniles are given inTable 5. The cruising, sustained, anddarting speeds of adult chinook salmonare about 1.1, 3.3, and 6.8 m/s,respectively (Bell 1973). Maximumspeeds depend on fish size, watertemperature, dissolved oxygen concen-trations, and stage of maturity.

The estimation of streamflowrequirements for juvenile salmonids isextremely complex due to the inter-action of numerous physical, chemical,and biological factors. The InstreamFlow Incremental Methodology (IFIM)was developed by the USFWS CooperativeInstream Flow Service Group to predictthe effects of a decline in flow andspace on freshwater fish populations(Bovee 1982). This procedure, ahydraulic simulation model that incor-porates fish age and species-specifichabitat preference data, is in usethroughout the western United States.Flow requirements for chinook salmonin large rivers are complex, butseveral studies have associated highsurvival of downstream migrants withhigh discharges in the spring(Wetherall 1970; CDFG 1975; Kjelsonand Raquel 1981; Kjelson et al. 1982).Survival of chinook salmon smolts inthe Sacramento River was highlycorrelated (r = .94) with freshwaterinflow in the spring and estuarinewater temperatures (Kjelson et al.1982). Various data support the viewthat years of high freshwater inflowin the San Joaquin River result ingreater return of spawning adults2.5 years later (CDFG 1975; Kjelsonand Raquel 1981).

Turbidity

Juvenile salmonids are capableof tolerating turbidity as high as1,000 ppm, but reductions of primaryfood production and feedingefficiency are likely at much lowerturbidities (Bell 1973). The migra-tion of adult salmon may be inhibitedat turbidities of 4,000 ppm (Bell

17

1973), and chinook salmon are reportedto avoid turbid waters if given achoice (Cordone and Kelley 1961).Direct harm to fish by excessivesuspended sediments is probably rarein nature and can be combatted inpart by mucous secretions that flushgill membranes. Abrasion and cloggingof gill lamellae may result underextreme turbidities and are related tothe size and hardness of the suspendedmaterial (Cordone and Kelley 1961).Prolonged exposure to highly turbidwaters may cause thickening of gilllamellae, which reduces oxygen-carbondioxide exchange efficiency resultingin an increase in vulnerability todisease (Bell 1973). Silt depositsare more damaging to salmon than siltsuspended in the water column.

Heavy Metals

Acid-mine wastes from the SpringCreek drainage have caused numerouskills of chinook salmon, steelhead

18

trout, and other species in theSacramento River between Keswick Damand Cottonwood Creek (a distance of 33river mi) (USFWS 1959; Prokopovich1965; Nordstrom 1977). Of the fourmost abundant metals in the minewaste, copper and zinc are extremelytoxic to chinook salmon. Since 1963,the wastes have been collected inSpring Creek Reservoir and metered intoKeswick Reservoir at levels thouqht tobe safe for anadromous fish (Finlaysonand Ashuckian 1979). In 1978, newinterim release schedules proposed byWilson (1978) allow for maximum dis-solved copper and zinc concentrationsof 5 pg/l and 64 pg/l, respectively(Finlayson and Verrue 1980). Recentlythe water quality program to partiallycontrol metal concentrations in theSacramento River (from acid-minewastes from Spring Creek) hascurtailed the number of fish kills(Wilson et al. 1981). The sublethaleffects on chinook salmon and otherfish species caused by chronic expo-sure to the metals are not known.

Alderdice, D.F., W.P. Wickett, andJ.R. Brett. 1958. Some effects oftemporary exposure to low dissolvedoxygen levels on Pacific salmoneggs. J. Fish. Res. Board Can.15:229-250.

Bams, R.A. 1969. Adaptations ofsockeye salmon associated withincubation in stream gravels. Pages71-87 in T.G. Northcote, ed.Symposium on salmon and trout instreams. H.R. MacMillan Lectures inFisheries, University of BritishColumbia, Vancouver.

Barns, R.A. 1976. Survival andpropensity for homing as effected bypresence or absence of locallyadapted paternal genes in twotransplanted populations of pinksalmon (O. gorbuscha). J. Fish.Res. Board Can. 33:2716-2725.

Banks, J.W. 1969. A review of theliterature on the upstream migrationof adult salmonids. J. Fish Biol.1:85-136.

LITERATURE CITED

Instream Flow Inf. Pap. No. 12.FWS/OBS-82/26. 248 pp.

Brannon, E.L. 1981. Orientationmechanisms of homing salmonids.Pages 217-219 i n E.L. Brannon andE.O. Salo, eds. Salmon and troutmigratory behavior symposium. Uni-versity of Washington, Seattle.

Brett, J.R. 1952. Temperature toler-ance in young Pacific salmon, genusOncorhynchus. 3. Fish. Res. BoardCan. 9:265-323.

Briggs, J.C. 1953. The behavior andreproduction of salmonid fishes ina small coastal stream. Calif. FishGame Fish Bull. No. 94. 62 PP.

Burner, C.J. 1951. Characteristics ofspawning redds of Columbia Riversalmon. U.S. Fish Wildl. Serv. Fish.Bull. 52(61):97-110.

Barnhart, R.A., and 3.6. Giebink.1983. Food habits of juvenilechinook salmon in the lower AmericanRiver from March 11, 1983 to June 7,1983. Calif. Coop. Fish. Res. Unit,unpubl. rep. 20 pp.

California Department of Fish andGame. 1971. An assessment ofFederal water projects adverselyaffecting California salmon andsteelhead resources. II. FriantDam. California Department of Fishand Game, Sacramento. 11 PP.

Bell, M.C. 1973. Fisheries handbookof engineering requirements and bio-logical criteria. U.S. Army Corpsof Engineers, North Pacific DivisionContract No. DACW57-68-C-0086.

California Department of Fish andGame. 1972-84. California trout,salmon,. and warmwater fish produc-tion and costs. Calif. Dep. FishGame, Inland Fish. Admin. Reps. 72-5, 73-5, 74-2, 75-1, 75-2, 76-5, 77-3, 78-3, 80-1, 82-5, 84-l.

Bovee, K.D. 1982. A guide to streamhabitat analysis using the instreamflow incremental methodology.

19

California Department of Fish andGame. 1975. Interagency ecologicalstudy program for the Sacramento-San

Joaquin Estuary. 4th Annu. Rep.1974. 121 pp.

Cannon, T.C. 1982. The importance ofthe Sacramento-San Joaquin Estuaryas a nursery area of young chinooksalmon, striped bass, and otherfishes. Rep. to Natl. Mar. Fish.Serv. Southwest Region. 102 pp.

Chapman, D.W. 1962. Aggressivebehavior in juvenile coho salmon asa cause of emigration. J. Fish.Res. Board Can. 19:1047-1080.

Chapman, D.W., and T.C. Bjornn. 1969.Distribution of salmonids instreams, with special reference tofood and feeding. Pages 153-176 inT.G. Northcote, ed. Symposium ofsalmon and trout in streams. H.R.MacMillan Lectures in Fisheries,University of British Columbia,Vancouver.

Chapman, W.M. 1943. The spawning ofchinook salmon in the main ColumbiaRiver. Copeia 1943:168-170.

Combs, B. D. 1965. Effect of tem-perature on development of salmoneggs* Prog. Fish-Cult. 27:134-137.

Combs, B.D., and R.E. Burrows. 1957.Threshold temperatures for thenormal development of chinook salmoneggs. Prog. Fish-Cult. 19:3-6.

Cordone, A.J., and D.W. Kelley. 1961.The influence of inorganic sedimenton the aquatic life of streams.Calif. Fish Game 47:189-228.

Davis, J.C. 1975. Minimal dissolvedoxygen requirements of aquatic lifewith emphasis on Canadian species:a review. J. Fish. Res. Board Can.32:2295-2332.

Denega, M.M. 1973. Age compositionand growth rates of chinook salmonfrom northern California salmontroll fishery. M.S. Thesis. Hum-boldt State University, Arcata. 56pp.

Dill, L.M. 1969. The subgravelbehavior of Pacific salmon larvae.Pages 89-100 in T.G. Northcote, ed.Symposium on salmon and trout instreams. H.R. MacMillan Lectures inFisheries, University of BritishColumbia, Vancouver.

Everest, F.H., and D.W. Chapman. 1972.Habitat selection and spatial inter-action by juvenile chinook salmonand steelhead trout in two Idahostreams. J. Fish Res. Board Can.29:91-100.

Ewing, R.D., S.L. Johnson, H.J.Pribble, and J.A. Lichatowich.1979. Temperature and photoperiodeffects on gill (Na +K ) -ATPaseactivity in chinook salmon (Oncor-hynchus tshawytscha). J. FishRes. Board Can. 36:1347-1353.

Ewing, R.D., H.J. Pribble, S.L.Johnson, C.A. Fustish, J. Diamond,and J.A. Lichatowhich. 1980.Influence of size, growth rate, andphotoperiod +on cyclic changes ingill (Na +K )ATPase activity chinook salmon (Oncorhynchus

Fast, D.E., Q.J. Stober, S. C. Crumley,and E.S. Killebrew. 1981. Survivaland movement of chinook' and cohosalmon alevins in hypoxic environ-ments. Pages 51-60 _in E.L. Brannonand E.O. Salo, eds. Salmon andtrout migratory behavior symposium.University of Washington, Seattle.

Finlayson, B.J., and S.H. Ashuckian.1979. Safe zinc and copper levelsfrom the Spring Creek drainage forsteelhead trout in the upper Sacra-mento River, California. Calif.Fish Game 65:80-99.

Finlayson, B.J., and K.M. Verrue.1980. Estimated safe zinc andcopper levels for chinook salmon,Oncorhynchus tshawytscha,Upper SacramentoR

in theiver, California.

Calif. Fish Game 66:68-82.

20

Forsberg, B.O., J.A. Johnson, and S.M.Klug. 1977. Identification, dis-tribution, and notes on food habitsof fish and shellfish in TillamookBay, Oregon. Oreg. Fish Wildl.Research Section Contract No. 14-16-OOOl-5456RBS. 117 pp.

Frey, H.W., ed. 1971. California'sliving marine resources and theirutilization. California Departmentof Fish and Game, Sacramento. 148PP.

Gangmark, H.A., and R.G. Bakkala.1960. A comparative study of stableand unstable spawning areas forincubating king salmon at MillCreek. Calif. Fish Game 46:151:164.

Gilbert, C.H. 1913. Age at maturityof the Pacific coast salmon of thegenus Oncorhynchus. U.S. Bur. Fish.,Fish. Bull. 32(1914):1-22.

Godin, J .G .T . 1981. Migrations ofsalmonid fishes during early lifehistory phases: daily and annualtiming. Pages 22-50 in E.L.Brannon and E.O. Salo, eds. Salmonand trout migratory behavior sympo-sium. University of Washington,Seattle.

Grau, E.G. 1981. Is the lunar cyclea factor timing the onset of salmonmigration? Pages 184-189 in E.L.

and E.O. Salo, eds. Salmonand trout migratory behavior sym-posium. University of Washington,Seattle.

Gray, R.H., and J.M. Haynes. 1979.Spawning migration of adult chinooksalmon (Oncorhynchus tshawytscha)carrying external and internal radiotransmitters. J. Fish. Res. BoardCan. 36:1060-1064.

Hallock, R.J. 1983. Sacramento Riverking salmon life history patterns atRed Bluff, California. Unpubl. Cen-tral Valley Project report. Cali-fornia Department of Fish and Game,Red Bluff.

Hallock, R.J., and D.H. Fry. 1967.Five species of salmon, Oncor-hynchus, in the Sacramento River,California. Calif. Fish Game 53:5-22.

Hallock, R.J., and W.F. Van Woert.1959. A survey of anadromous fishlosses in irrigation diversions fromthe Sacramento and San JoaquinRivers, Calif. Fish Game 45:227-296.

Hallock, R . J . , R.F. Elwell, and D.H.Fry. 1970. Migrations of adult kinqsalmon, Oncorhynchus tshawytscha, inthe San Joaquin Delta, as demon-strated by the use of sonic tags.Calif. Fish Game Fish Bull. 151. 92pp.

Hart, J.L. 1973. Pacific fishes ofCanada. Fish. Res. Board Can. Bull.180. 740 pp.

Hartt, A.C. 1980. Juvenile salmonidsin the oceanic ecosystem: the cri-tical first Pages 25-57 inW.J. McNeil and D.C. Himsworth, eds.Salmonid ecosystems of the NorthPacific. Oregon State UniversityPress and Oregon State Univ. SeaGrant College Program, Corvallis.

Hasler, A.D., and A.T. Scholz. 1983.Olfactory imprinting and homing insalmon. Springer-Verlag, Berlin,Germany. 134 pp.

Hasler, A.D., and W.J. Wisby. 1951.Discrimination of stream odors byfish and its relation to parentstream behavior. Am. Nat. 85(823):223-238.

Healey, M.C. 1980. Utilization ofthe Nanaimo River Estuary by juve-nile chinook salmon (Oncorhynchustshawytscha). U.S. Natl. Mar. Fish.Serv. Fish. Bull. 77:653-668.

Healey, M.C. 1982. Juvenile Pacificsalmon in estuaries: the life sup-port system. Pages 315-341 in V.Kennedy, ed. Estuarine comparisons.Academic Press, New York.

21

Healey, M.C. 1983. Coastwide distri-bution and ocean migration patternsof stream and ocean type chinooksalmon, Qncorhvnchus tshawytscha.Can. Field Nat. 97:427-433.

Healey, M.C., and W.R. Heard. 1984.Inter- and intra-population vari-ation in the fecundity of chinooksalmon (Oncorhynchus tshawytscha)and its relevance to life historvtheory. Can. J. Fish. Aquat. Sci.41:476-483.

Heifetz, J. 1982. Use of radio tele-metry to study upriver migration ofadult river chinook salmon. M.S.Thesis. Humboldt State University,Arcata, Calif. 65 pp.

Hoar, W.S. 1953. Control and timingof fish migration. Biol. Rev. 28:437-452.

Hoar, W.S. 1976. Smolt transfor-mation: evolution, behavior, andphysiology. J. Fish. Res. BoardCan. 33:1233-1252.

Hoopaugh, D.A., and A.C. Knutson, Jr.1979. Chinook (king) salmonspawning stocks in California'sCentral Valley, 1977. Calif. Dep.Fish Game, Anad. Fish. Branch Admin.Rep. No. 79-11. 36 pp.

Jensen, P.T. 1971. Salmon andsteelhead.' Pages 1-13 in Report tothe State Water Resources ControlBoard. Calif. Dep. Fish Game,Environ. Serv. Admin. Rep. No. 71-2.

Junge, C.O., and L.A. Phinney. 1963.Factors influencing the return offall chinook salmon (Oncorhynchustshawytscha) to Spring Creek Hatch-ery. U.S. Fish Wildl. Serv. Spec.Sci. Rep. Fish. No. 455. 32 pp.

Kjelson, M.A., and P.F. Raquel. 1981.Influences of freshwater inflow onchinook salmon (Oncorynchustshawytscha in the Sacramento-SanJoaquin Estuary. Pages 88-108 inR.D. Cross and D.C. Williams, eds.

Proceedings of the national sym-posium on freshwater inflow toestuaries, Vol. 2. U.S. Fish Wildl.Serv. FWS/OBS-81/04.

Kjelson, M.A., P.F. Raquel, and F.W.Fisher. 1982. Life history offall-run juvenile chinook salmon,Oncorhvnchus tshawytscha, in theSacramento-San Joaquin Estuary,California. Pages 393-411 in V.Kennedy, ed. Estuarine comparisons.Academic Press, New York.

Knutson, A.C., Jr. 1980. Chinook(king) salmon spawning stocks inCalifornia's Central Valley, 1978.Calif. Dep. Fish Game, Anad. Fish.Branch Admin. Rep. No. 80-6. 32 pp.

Leitritz, E., and R.C. Lewis. 1980.Trout and salmon culture (hatcherymethods) Calif. Fish Game Fish Bull.No. 164. 197 pp.

Levy, D.A., and T.G. Northcote. 1982.Juvenile salmon residence in a marsharea of the Fraser River Estuary.Can. J. Fish. Aquat. Sci. 39:270-276.

Lister, D.B., and H.S. Genoe. 1970.Stream habitat utilization by cohab-iting underyearlings of chinook(Oncorhynchus tshawytscha) and coho(0. kisutch) salmon in the BigQualicum River, British Columbia:J. Fish. Res. Board Can. 27:1215-1224.

Mathews, S.B., and G.S. Brown. 1970.Economic evaluation of the 1967sport salmon fisheries of Wash-ington. Wash. Fish Game Tech. Rep.No. 2, Olympia. 19 pp.

McConnell, R.J., and G.R. Snyder.1972. Key to identification of ana-dromous juvenile salmonids in thePacific Northwest. US. Natl. Mar.Fish. Serv. Tech. Rep. Natl. Mar.Fish Serv. Circ. 366. 5 pp.

Menchen, R.S. 1981. Predation byyearling steelhead, Salmo gairdneri,

22

released from Coleman National FishHatchery, on naturally producedchinook salmon, Oncorhynchustshawytscha, fry and eggs in BattleCreek, 1975. Calif. Fish Game,Anad. Fish. Office Rep. 6 pp.

Merkel. T.J. 1957. Food habits ofthe - king salmon (Oncorhynchustshawytscha) in the vicinity of SanFrancisco, California. Calif. FishGame 43:249-270.

Moyle, P.B. 1976. Inland fishes ofCalifornia. University of Cali-fornia Press, Berkeley. 405 pp.

Myers, K.W. 1980. An investigationof the utilization of four studyareas in Yaquina Bay, Oregon, byhatchery and wild juvenile sal-monids. M.S. Thesis. University ofOregon, Corvallis. 243 pp.

National Marine Fisheries Service.1940-75. Fishery statistics of theUnited States. Statistical DigestNos. 4(1940), 18(1945) 27(1950),41(1955), 53(1960), 59(1965),64(1970), 69(1975).

National Marine Fisheries Service.1979. Saltwater adaptation of cohosalmon, spring and fall chinook sal-mon, and steelhead. A study toassess status of smoltification andfitness for ocean survival of chi-nook, coh o and steelhead. U.S.Natl. Mar. Fish. Serv. Coastal Zoneand Estuarine Division. Annu. Rep.for FY 1978-79, Project 817. 31 pp.(+ appendices).

National Marine Fisheries Service.1984. Fisheries of the UnitedStates, 1983. U.S. Natl. Mar.Fish. Serv. Curr. Fish. Stat. No.8320. 121 pp.

Needham, P.R., O.R. Smith, and H.A.Hanson. 1940. Salmon salvage pro-blems in relation to Shasta Dam,California, and notes on the biologyof the Sacramento River salmon.Trans. Am. Fish. Soc. 70:55-69.

Nordstrom, D. 1977. Hydrogeochemicaland microbiological factors affect-ing the heavy metal chemistry of anacid mine drainage system. Ph.D.Dissertation. Stanford University,Palo Alta, Calif. 210 pp.

Orsi, J.J. 1967. Dissolved oxygenrequirements of fish and inver-tebrates. Pages 48-68 in Delta fishand wildlife protection study, Rep.No. 6. The Resources Agency ofCalifornia, Sacramento.

Pacific Fishery Management Council.1984. A review of the 1983 oceansalmon fisheries and status ofstocks and management goals for the1984 salmon season off the coasts ofCalifornia, Oregon, and Washington.Pacific Fishery Management Council,Portland.

Parker, R.R. 1968. Marine mortalityschedules of pink salmon of theBella Coola River, central BritishColumbia. J. Fish. Res. Board Can.25:757-794.

Peterman, R.M. 1978. Testing fordensity-dependent marine survival inPacific salmonids. J. Fish. Res.Board Can. 35:1434-1450.

Peterman, R.M., and M. Gatto. 1978.Estimation of functional responsesof predators on juvenile salmon. J.Fish. Res. Board Can. 35:797-808.

Piper, R.G., I.B. McElwain, L.E. Orme,J.P. McCraren, L.G. Fowler, and J.R.Leonard. 1982. Fish hatchery man-agement. U.S. Fish. Wildl. Serv.,Washington, D.C. 517 pp.

Prokopovich, N. 1965. Siltation andpollution problems in Spring Creek,Shasta County, California. J. Am.Water Works ASSOC. 57:986-995.

Quinn, T.P. 1981. A model for salmonnavigation on the high seas. Pages229-237 in E.L. Brannon and E.O.Salo, edsT Salmon and trout migra-

23

tory behavior symposium. Universityof Washington, Seattle.

Reavis, R.L., Jr. 1981a. Chinook(king) salmon spawning stocks inCalifornia's Central Valley, 1979.Calif. Dep. Fish Game, Anad. Fish.Admin. Rep. No. 81-4. 31 pp.

Reavis, R.L., Jr. 1981b. Chinook(king) salmon spawning stocks inCalifornia's Central Valley, 1980.Calif. Dep. Fish Game, Anad. Fish.Branch Admin. Rep. No. 81-7. 36 pp.

Reavis, R.L., Jr. 1983. Annualreport of chinook salmon spawningstocks in California's CentralValley, 1981. Calif. Dep. FishGame, Anad. Fish. Branch Admin. Rep.No. 83-Z. 41 pp.

Reimers, P.E. 1968. Social behavioramong juvenile fall chinook salmon,J. Fish. Res. Board Can. 25:2005-2008.

Reimers, P.E. 1973. The length ofresidence of juvenile fall chinooksalmon in Sixes River, Oregon.Oreg. Fish. Comm. Res. Rep. 4(2):1-43.

Reiser, D.W., and T.C. Bjornn. 1979.Habitat requirements of anadromoussalmonids. Pages l-54 in W.R.Meeham, ed. Influence of forest andrangeland management on anadromousfish habitat in the western UnitedStates and Canada. U.S. For. Serv.Gen. Tech. Rep. PNW-96.

Rich, W.H. 1920. Early life historyand seaward migration of chinooksalmon in the Columbia and Sacra-mento Rivers. U.S. Bur. Fish. Bull.37:1-74.

Ricker, W.E. 1980. Causes in thedecrease in age and size of chinooksalmon (Oncorhynchus tshawytscha).Can. Tech. Rep. Fish. Aquat. Sci.No. 944. 25 pp.

Ricker, W.E. 1981. Changes inaverage size and age of Pacificsalmon. Can. J. Fish. Aquat. Sci.38:1636-1656.

Rothschild, B.J. 1972. Fisherypotential from the oceanic regions.Pages 95-106 in_ C.B. Miller, ed.The biology of the oceanic Pacific.Oregon State University, Corvallis.

Rounsefell, G.A. 1957. Fecundity ofNorth American Salmonidae. U.S.Fish. Wildl. Serv. Fish. Bull. 57:451-468.

Rutter, C. 1904. Natural history ofthe quinnat salmon. U.S. Fish.Comm. Bull. 22(1902):65-141.

Schaffter, R.G. 1980. Fishoccurrence, size, and distributionin the Sacramento River near Hood,California during 1973 and 1974.Calif. Fish Game Anad. Fish. Admin.Rep. No. 80-3. 76 pp.

Shepard, M.F. 1981. Status a n dreview of the knowledge pertainingto the estuarine habitat require-ments and life history of chum andchinook salmon juveniles in PugetSound. Final Rep. Wash. Coop.Fish. Res. Unit, University of Wash-ington, Seattle. 113 pp.

Sholes, W.H., and R.J. Hallock. 1979.An evaluation of rearing fall-runchinook salmon, Oncorhynchustshawytscha, to yearlings atFeather River Hatchery, with a com-parison of returns from hatchery anddownstream release. Calif. FishGame 65:239-255.

Sibert, J.R., T.J. Brown, M.C. Healey,B.A. Kask. and R.J. Naimen. 1978.Detritus-based food webs: exploi-tation by juvenile chum salmon(Oncorhynchus keta). Science 196:- -649 -650.

Silver, S.T., C.E. Warren, and P.Doudoroff. 1963. Dissolved oxygenrequirements of developing steelhead

trout and chinook salmon embryos atdifferent water velocities. Trans.Am. Fish. Sci. 92:327-343.

Simenstad, C.A. 1983. The ecology ofestuarine channels of the PacificNorthwest coast: a community pro-file. U.S. Fish Wildl. Serv. FWS/OBS-83/05. 181 pp.

Slater, D.W. 1963. Winter runchinook salmon in the SacramentoRiver, California, with notes onwater temperature requirementsduring spawning. U.S. Fish Wildl.Serv. Spec. Sci. Rep. Fish. No.461:1-9.

Snyder, J.O. 1924. Young salmon atsea. Calif. Fish Game 10:62-64.

Snyder, J.O. 1931. Salmon of theKlamath River, California. Calif.Fish Game Fish Bull. 34. 130 pp.

Stein, R.A., P.E. Reimers, and J.D.Hall. 1972. Social interactionbetween juvenile coho (Oncorhynchuskisutch) and fall chinook salmon(Oncorhynchus tshawytscha) in SixesRiver, Oregon. J. Fish. Res. BoardCan. 29:1737-1748.

Taylor, S.N. 1974. Chinook (king)salmon spawning stocks inCalifornia's Central Valley, 1972.Calif. Fish.Game. Anad. Fish. Admin.Rep. 74-6. 32 pp.

Thomas, A.E. 1975. Migration ofchinook salmon fry from simulatedincubation channels in relation towater temperature, flow, and turbi-dity. Prog. Fish-Cult. 37:219-223.

Thompson, K. 1972. Determiningstream flows for fish life. Pages31-50 in Proceedings instream flowrequirement workshop. Pacific North-west River Basin Commission, Van-couver, Wash.

U.S. Fish and Wildlife Service. 1959.Effects of mine-waste pollution onanadromous and resident fish in

U . S. Fish and Wildlife Service. 1970-81. Propagation of fishes fromnational fish hatcheries. Divisionof Hatcheries and Fish ResourceManagement, U.S. Fish Wildl. Serv.,Fish Distrib. Rep. NOS. 6 through16.

U.S. Fish and Wildlife Service. 1980.Annual report Klamath Riverfisheries investigations program,1980. U.S. Fish Wildl. Serv., Fish.Assist. Office, Arcata, Calif. 107pp.

Upper Sacramento River, ShastaCounty, California. 15 pp.

U.S. Fish and Wildlife Service. 1981.Annual report Klamath River fish-eries investigations program, 1981.U.S. Fish Wildl. Serv., Fish.Assist. Off ice, Arcata, Calif.131 pp.

U.S. Fish and Wildlife Service. 1982.Annual report Klamath River fish-eries investigations program, 1982.U.S. Fish Wildl. Serv., Fish.Assist. Office, Arcata, Calif. 153PP.

U.S. Fish and Wildlife Service. 1983.Annual report Klamath River fish-eries investigations program, 1983.U.S. Fish Wildl. Serv., Fish.Assist. Office, Arcata, Calif. 133PP.

U.S. Fish and Wildlife Service. 1984.Annual report Klamath River fish-eries investigations program, 1984.U.S. Fish Wildl. Serv., Fish.Assist. Office, Arcata, Calif. 142pp.

Vronskiy, B.B. 1972. Reproductivebiology of the Kamchatka Riverchinook salmon (Oncorhynchus tsha-wytscha). J. Ichthyol. 12:259-273.

Wagner, H.H., F.P. Conte, and J.L.Fessler. 1969. Development ofosmotic and ionic regulation in two

25

races of chinook salmon (Oncor-hynchus tshawytscha). Comp.Biochem. Physiol. 29:325-341.

Wahle, R., R. Vreeland, and R. Lander.1974. Bioeconomic contribution ofColumbia River hatchery coho salmon,1965 and 1966 broods, to the Pacificsalmon fisheries. U.S. Natl. Mar.Fish. Serv. Fish. Bull. 72:139-169.

Wales, J.H., and M. Coots. 1954.Efficiency of chinook salmonspawning in Fall Creek, California.Trans. Am. Fish. Soc. 84:137-149.

Walters, C. J R. Hillburn, R.M.Peterman, a n d M. Staley. 1978.Model for examining early oceanlimitation of Pacific salmon pro-duction J. Fish. Res. Board Can.35:1303-1315.

Warner, G.H., D.H. Fry, and A.N.Culver. 1961. History of yearlingking salmon marked and released atNimbus Hatchery. Calif. Fish Game47:343-355.

Weaver, C.R. 1963. Influence ofwater velocity upon orientation andperformance of adult migrating sal-monids. U.S. Fish Wildl. Serv.Fish. Bull. 63:97-121.

Wetherall, J.A. 1970. Estimation ofsurvival rates for chinook salmonduring their downstream migration inthe Green River, Washington. Ph.D.Dissertation. University of Wash-ington, Seattle. 170 pp.

Whitmore, C.M., C.E. Warren, and P.Donderoff. 1960. Avoidance reac-tions of salmonids and centrarchidfishes to low oxygen concentrations.Trans. Am. Fish. Soc. 89:17-26.

Wickmire, R.H., and D.E. Stevens.1971. Migration and distribution ofyoung king salmon, Oncorhynchustshawytscha, in the Sacramento Rivernear Collinsville. Calif. Dep. FishGame Anad. Fish. Branch Admin. Rep.No. 71-4. 18 pp.

Wilson, D. 1978. Proposed interimrelease flows in the SacramentoRiver. Calif. Dep. Fish. Game,Region 1, Redding, Calif. Memoran-dum to California Regional WaterQuality Control Board - CentralValley Region, 31 August 1978. 5 pp.

Wilson, D., B. Finlayson, and N.Morgan. 1981. Copper, zinc, andcadmium concentrations of residenttrout related to acid-mine wastes.Calif. Fish Game 67:176-186.

Wright, S. 1981. ContemporaryPacific salmon fisheries management.N. Am. J. Fish Manage. 1:29-40.

Zaugg, W.S. 1981. Relationshipsbetween smolt indices and migrationin controlled and natural environ-ments. Pages 173-183 in E.L.Brannon and E.O.Salo, e d s .and trout migratory behavior sympo-sium. University of British Colum-bia, Vancouver.

26

REPORT DOCUMENTATION 1. REPORT NO. 2.

PACE Biological Report 82(11.49)*/4I. 7111a l nd SUbllflO

Species Profiles: Life Histories and EnvironmentalRequirements of Coastal Fishes and Invertebrates

;<al morn

;D. l orformtn~ Orgrnczrtcon Wwmo me AderasCalifornia Cooperative Fishery Research UnitHumboldt State UniversityArcata, CA 95521

;LZ Soonronry O~onlxotlon Nomo on4 Addrosa

National Coastal Ecosystems Team U.S. Army Corps of EngineersFish and Wildlife Service Waterways Experiment StationU.S. Department of the Interior P.O. Box 631Washington, DC 20240 Vicksburg, MS 39180

IIS. Sugpttrmontorl, Na(os

*U.S. Army Corps of Engineers Report No. TR EL-82-4i

3. a*clt?~*-~ s *CCossIQll No

I1 April 1986

11. tintfOCtlCl w Cront(G) No.

Species profiles are literature summaries of the taxonomy, morphology, distribution,abundance, life history, and environmental requirements of coastal aquatic species. Theyare prepared to assist in environmental impact assessment. The chinook salmon(Oncbrhynchus tshawytscha) is a valuable sport and commercial fish species and accountedfor over 69% of the salmon caught off the California coast from 1971 through 1983.Chinook salmon spawning runs in the Sacramento River, the major producer of chinooksalmon in California, are divided into fall, late fall, winter, and spring runs. O'ther-coastal rivers have fall and spring runs of chinook or only a fall run. After hatching,the sac-fry live in the gravel for a month or longer before they emerge as fry. Somefry migrate immediately to saltwater, others remain 2 to 12 months in freshwater be$oremigrating. They remain in the ocean from 1 to 7 years; most females mature and return tofreshwater to spawn after 2 to 4 years at sea. Some males return to spawn after onjy1 year in the ocean, but most return after 2 to 4 years. All chinook salmon die af'berthey reenter freshwater, whether they spawn or not.

I

Fishes EstuariesGrowth Animal migrations

b. I4ontlfiacr/Opan-Cnded lams

Habitat requirementsLife historyChinook salmonOncorhynchus tshawytscha

Salinity requirementsTemperature requirements

Se. #NC’,.-:I? :s>

U.S.G.P.O. 1986/661-638