Libiary 

Na:!onal Wetlands Research Center 

CT. S. Fish and Wildlife Service 

730 Cajundome Boulevard 

Lafayette. La. 7Q5Qs 

Biological Report 82 ( 1 1.40) 

April 1086 

TR EL-82-4 

Species Profiles: Life Histories and 

Environmental Requirements of Coastal Fishes 

and Invertebrates (Pacific Southwest) 

CHINOOK SALMON 

QL 

155 

.S63 

no. 82 

11.49 

Coastal Ecology Group 

L 

Fish and Wildlife Service Waterways Experiment Station 

U.S. Department of the Interior U.S. Army Corps of Engineers 

Biological Report 82t11.49) 

TR EL-84-4 

April 1986 

Species Profiles: Life Histories and Environmental Requirements 

of Coastal Fishes and Invertebrates (Pacific Southwest) 

CHINOOK SALMON 

Mark A. Allen and Thomas J. Hassler 

California Cooperative Fishery Research Unit 

Humboldt State University 

Arcata, CA 95521 

Project Officer 

John Parsons 

National Coastal Ecosystems Team 

U.S. Fish and Wildlife Service 

1010 Gause Boulevard 

Slidell, LA 70458 

Performed For 

Coastal Ecology Group 

Waterways Experiment Station 

U.S. Army Corps of Engineers 

Vicksburg, MS 39180 

and 

National Coastal Ecosystems Team 

Division of Biological Services 

Research and Development 

Fish and Wildlife Service 

U.S. Department of the Interior 

Washington, DC 20240 
This series should be referenced as follows: 

U.S. Fish and Wildlife Service. 1983-19 . Species profiles: life histories 

and environmental requirements of coastfi fishes and invertebrates. U.S. Fish 

Wildl. 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 and 

environmental requirements of coastal fishes and invertebrates (Pacific 

Southwest)--chinook salmon. U.S. Fish Wildl. Serv. Biol. Rep. 82l11.49). 

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 profiles 

are designed to provide coastal managers, engineers, and biologists with a brief 

comprehensive sketch of the biological characteristics and environmental 

requirements of the species and to describe how populations of the species may be 

expected to react to environmental changes caused by coastal development. Each 

profile has sections on taxonomy, life history, ecological role, environmental 

requirements, and economic importance, if applicable. A three-ring binder is 

used 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 Engineers 

and the U.S. Fish and Wildlife Service. 

Suggestions or questions regarding this report should be directed to one Of 

the following addresses. 

Information Transfer Specialist 

National Coastal Ecosystems Team 

U.S. Fish and Wildlife Service 

NASA-Slide11 Computer Complex 

1010 Gause Boulevard 

Slidell, LA 70458 

or 

U.S. Army Engineer Waterways Experiment Station 

Attention: WESER-C 

Post Office Box 631 

Vicksburg, MS 39180 

iii 
Multiply EY To Obtain 

millimeters (mn) 0.03937 inches 

centimeters (cm) 0.3937 inches 

meters (m) 3.281 feet 

kilometers (km) 0.6214 miles 

square meters (m2) 

square kilometers (km2) 

hectares (ha) 

liters (1) 

cubic meters (m3) 

0.2642 

35.31 

cubic meters 0.0008110 

gallons 

cubic feet 

acre-feet 

milligrams (mg) 

grams (9) 

kilograms (k 

metric tons 9 

) 

t) 

metric tons 

kilocalories (kcal) 

0.00003527 ounces 

0.03527 ounces 

2.205 pounds 

2205.0 pounds 

1.102 short tons 

3.968 British thermal units 

Celsius degrees 1.8(Y) + 32 Fahrenheit degrees 

inches 25.40 millimeters 

inches 2.54 centimeters 

feet (ft) 0.3048 meters 

fathoms 1.829 meters 

miles (mi) 1.609 kilometers 

nautical miles (rmi) 1.852 kilometers 

square feet (ft2) 0.0929 square meters 

acres 

square miles (mi2) 

0.4047 hectares 

2.590 square kilometers 

gallons (gal) 3.785 

cubic feet (ft3) 

liters 

0.02831 cubic meters 

acre-feet 1233.0 cubic meters 

cunces (02) 28.35 

pounds (lb) 0.4536 

short tons (ton) 0.9072 

grams 

kilograms 

metric tons 

kilocalories 

CONVERSION TABLE 

Metric to U.S. Customary 

10.76 square feet 

0.3861 

2.471 

square miles 

acres 

U.S. Customary to Metric 

British thermal units (Btu) 0.2520 

Fahrenheit degrees 0.5556("F 

iv 

32) Celsius degrees 
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 .......................................................... 

iii 

iv 

vi 

1 

1 

3 

3 

3 

4 

5 

6 

7 

7 

8 

9 

:; 

11 

13 

13 

:; 

14 

14 

:; 

:3 

18 

19 

V 
ACKNOWLEDGMENTS 

We are grateful for reviews by Richard J. Hallock and Kenneth A. Hashagen, 

Jr., California Department of Fish and Game. 

vi 
Figure 1. Chinook salmon. 

CHINOOK SALMON 

NOMENCLATURE/TAXONOMY/RANGE 

Scientific name . . . . . @corhvnchus 

tshawytscha (Walbaum) (Figure l).- 

Preferred common name . . . . Chinook 

salmon 

Other common names . . . . King, king 

salmon, Wee, quinnat, spring 

salmon. 

Class . . . . . . . . . . Osteichthyes 

Order . . . . . . . . . .Salmoniformes 

Family . . . . . . . . . . .Salmonidae 

Geographic range: Spawning populations of chinook salmon in North 

America are distributed from the 

Sacramento-San Joaquin River system 

in central California north to Point 

Hope, Alaska. Asian populations are 

distributed from Japan north to the 

Anadyr River, USSR. Introductions 

of young chinook salmon have 

established spawning populations and 

fisheries in rivers tributary to 

South Island, New Zealand, and the 

U.S. Laurentian Great Lakes. The 

major rivers in California that 

support spawning runs of chinook 

salmon are shown in Figure 2. 

MORPHOLOGY/IOENTIFICATION AIDS 

The following descriptions were 

taken from McConnell and Snyder 

(19721, Hart (19731, and Moyle (1976). 

Fin rays: Dorsal 10-14, anal 13-19, 

pelvic 10-11, and pectoral 14-19. The 

caudal fin is moderately forked; 

adipose is stout and prominent; a 

free-tipped flesh appendage inserts 

just above the pelvic. Cycloid 

scales, 130-165 pored scales on 

lateral line, 131-158 in rows above. 

Number of branchiostegal rays each 

side of jaw, 13-19; gill rakers rough 

and widely spaced, 6-10 on lower half 

of first gill arch; pyloric caeca, 

120-185. 

1 
420 

Northwest 

.------- 

Miles 

25 5p 

OREGON 

’ CALIFORNIA 1 

_.. .- _.._.. 

Kilomek~s 

1 Terminol Dam 

Cnnrtal Distribution 

42” 

2 

m 

: 

3 

D 

\ 

36O PACIFIC OCEAN 

36* 

Figure 2. The major rivers in the Pacific Southwest that support 

spawning runs of chinook salmon. 

however, were unable to adapt to the 

loss of their headwater spawning 

grounds and their numbers decreased. 

The construction of Friant Dam 

on the San Joaquin River in 1939 

blocked the spring-run of chinook 

salmon from their spawning grounds and 

they have all but disappeared (Hallock 

et al. 1970; California Department of 

Fish and Game 1971). Now (1971-84) 

only a fall-run population remains and 

averages only 10% of the fall-run of 

chinook salmon in the Sacramento River 

(Figure 4). 

Spring-run chinook salmon also 

ascend the Eel and Klamath River 

systems to spawn but have contributed 

less than 5% of all chinook salmon 

produced in California. Chinook 

salmon spawning runs have decreased in 

all California rivers, especiallv in 

the Sacramento and San Joaquin Rivers 

(Figure 4). 

The release of gonadal or thyroid hormones in adult salmon may 

stimulate upstream migration by 

modifying fish behavior in response 

to external variables that influence 

migration (Hoar 1953). An increase 

in the volume of stream flow is the 

54 56 5s 50 52 54 58 58 70 72 74 76 75 80 52 

YEAR 

Figure 4. The estimated number of 

fall-run chinook salmon (may include 

some spring-run fish) that returned 

yearly to the Sacramento and San 

Joaquin Rivers to spawn in 1953-83 

(data from Taylor 1974; Reavis 1983; 

PFMC 1984). 

most frequently cited environmental 

stimulus to upstream migration, but 

this relation is most evident in small 

rivers (Banks 1969). Changes in 

atmospheric pressure, water turbidity, 

water temperature, and dissolved 

oxygen are also known to influence 

upstream migration. 

Low dissolved oxygen and high 

water temperatures inhibited upstream 

movement of fall-run chinook salmon in 

the San Joaquin River (Hallock et al. 

1970). Most adult chinook salmon 

migrate upstream during the day 

(Needham et al. 1940; Banks 1969). 

Fall-run chinook typically migrate 

upstream at a rate of 5 to 14.5 km/day 

(Gray and Haynes 1979; Heifetz 1982). 

The homing of salmon to their 

parent stream after entering 

freshwater is well documented and is 

attributable to olfactory cues that 

are specific for each location and are 

"learned" by the juvenile salmon 

shortly before they migrate to the sea 

(Hasler and Wisby 1951; Hasler and 

Scholz 1983). Genetic history may 

also influence homing success (Barns 

1976). 

Salmon do not usually feed after 

entering freshwater and severe atrophy 

of the digestive system sets in before 

spawning begins. 

Spawning 

The female chinook salmon usually chooses a nesting site in gravel 

deposits at the lower lip of a pool 

just above a riffle (Burner 1951; 

Briggs 1953). The female makes a redd 

(an area containing several individual 

nests) by turning on her side and 

repeatedly flexing her body and tail 

to force gravel and fine sediment into 

the water column; these sediments are 

deposited a short distance downstream. 

The completed nest forms an oval depression with a mound of gravel 

located immediately downstream. 

4 
During spawning, a dominant male 

salmon accompanies the female and 

aggressively chases away other males 

attempting to enter the redd area. 

The eggs and sperm are released into 

the nest by the female and male 

simultaneously. Usually one or more 

males will position themselves 

alongside the female opposite the 

dominant male and release sperm. By 

the end of the spawning, as many as 10 

to 12 male salmon may have attempted 

to spawn with a single female (Briggs 

1953; Vronskiy 1972). 

After the eggs are released, the 

female usually moves just upstream and 

repeats the nest building and the 

spawning act. The fertilized eggs are 

buried 20 to 60 cm below the pravel 

surface with the excavation material 

from the new nest (Briggs 1953; 

Vronskiy 1972). The female will 

repeat the process several times 

before spawning is completed. Each 

completed redd may contain several 

nests; the overall size of the redd is 

directly related to the size of fish 

and inversely related to the size Of 

the substrate particles, water 

velocity, and density of spawners 

(Burner 1951; Vronskiy 1972). Female 

chinook salmon sometimes dig false 

redds (but do not deposit eggs there) 

before and after they build true redds 

(Briggs 1953). 

Each female may spawn over a 

period of 5 to 14 days. Unlike 

females of other salmon species, 

female chinook salmon may defend the 

redd from intruding females for 5 to 

9 days after spawning (Briggs 1953; 

Vronskiy 1972). 

After spawning, the salmon 

deteriorate rapidly, exhibitino large 

open wounds and heavy fungal 

infection. Life expectancy after 

spawning is 2 to 4 weeks (Briggs 

1953). 

5 

Eggs and Alevins - -_-_____ 

Fecundity varies greatly among 

chinook salmon of different 

populations. For example, fecundity 

of fall-run chinook salmon averages 

3,634 eggs per female in the Klamath 

River but 7,295 eggs in Sacramento 

River fish. Difference in female size 

alone cannot account for the variation 

in fecundity (Healey and Heard 1984). 

Chinook salmon eggs are large: 

6.3 to 7.9 mm in diameter (Rounsefell 

1957) and 0.35 to 0.40 grams in weight 

(Leitritz and Lewis 1980). 

The len9th of time reauired for 

hatching is inversely related to water 

temperature. Chinook salmon eggs have 

been successfully incubated and 

hatched at water temperatures of 4' to 

16' C; however, lower temperatures can 

be tolerated in the later stages of 

embryonic development (Combs and 

Burrows 1957; Combs 1965; Piper et al. 

1982). 

Chinook salmon eggs are 

particularly vulnerable to shock 

injury. Injury can result from gravel 

movement caused by bottom scouring, 

mechanical impaction, or superimposed 

spawning activity. Other causes of 

egg mortality are low dissolved 

oxygen, high concentrations of toxic 

chemicals, excessively high water 

temperatures, infestations with fungi 

or oligochaetes, predation by insects 

or fish, and heavy sedimentation. 

Under poor conditions the mortality of 

eggs may be as high as 95% (Wales and 

coots 1954; Gangmark and Bakkala 

1960). Under ideal conditions the 

mortality of the eggs may be as low as 

10% (Briggs 1953). 

After hatching, alevins (yolksac larvae) remain in the gravel 

interstices for a month or longer, 

during which time they exhibit the 

following three major distributional 

phases: a deeper submergence, a 

resting period, and an upward 

emergence (Dill 1969). Salmonid 
alevins are negatively phototactic and 

positively geotactic and thigmotactic; 

these characteristics serve to 

encourage further submergence into the 

gravel and prevent premature emergence 

(Godin 1981). After deeper submergence, alevins remain relatively 

inactive unless forced to disperse in 

response to excessive levels of carbon 

dioxide or metabolic waste (Dill 

1969), or to avoid desiccation during 

low flow (Fast et al. 1981). 

As the yolk sac is absorbed, 

alevins develop positive rheotactic 

and phototactic responses and begin an 

upward migration in the gravel (Dill 

1969). Intra-gravel movement of 

alevins is governed by gravel size, 

interstitial spacing, rate of water 

flow, dissolved gases, and water 

temperature (Dill 1969; Godin 1981). 

Fry and Smolts .- -_l_- 

Chinook salmon fry usually 

emerge from the gravel at night, 

probably as an antipredation measure 

(Barns 1969), and spend 1 to 18 months 

in freshwater. After emerging, most 

chinook salmon fry immediately 

disperse downstream, possibly because 

of their new nondemersal habits and 

loss of visual contact with the stream 

substrate (Reimers 1973). Diurnal 

dispersion has been observed during 

increases in water turbidity and 

temperature (Rutter 1904; Thomas 

1975). After emergence, the fry 

develop neutral buoyancy, begin 

exogenous feeding, and develop social 

behavior (Barns 1969). 

Chinook salmon fry in streams 

change habitats as they grow older. 

Lister and Genoe (1970) generalized 

changes in order as follows: "initial 

hiding, possibly in the gravel; 

association with bank cover; 

appearance along open shorelines; and 

finally, movement into higher velocity 

locations along the stream margin or 

farther out from shore." After the 

initial hiding period, chinook salmon 

fry seek fine substrates and low water 

velocities, progressively moving into 

deeper, faster, and rockier habitats 

(Lister and Genoe 1970; Everest and 

Chapman 1972). Overwintering springrun chinook juveniles hide under large 

rocks and debris, a habitat shift 

apparently triggered by low water 

temperature (Chapman and Bjornn 1969). 

As the fry begin to smoltl, they 

become silvery and slimmer and change 

their behavior; their territorial 

instincts break down, and they usually 

emigrate in schools downstream to the 

ocean. 

The osmoregulatory changes that 

allow tolerance of saltwater are 

somewhat more complex in chinook 

salmon than in coho salmon or steelhead trout (Salmo airdneri) (National 

Marine Fishery -9_'_7979* Service Zaugg 

1981). Unlike the fry OF other 

salmonids, those of chinook salmon 

tolerate high levels of serum 

chlorides and are able to rapidly 

acclimate to high salinities. As the 

fry age in freshwater, their tolerance 

to salinity gradually increases, and 

some enter estuaries without first 

developing the morphological characteristics of a smolt (Hoar 1976). 

The degree of salinity tolerance 

depends somewhat on prior acclimation, 

but fish size and growth rate have 

been identified in several studies as 

factors affecting salinity tolerance. 

The saltwater tolerance of larger fish 

of a given age is known to exceed that 

of smaller ones. Ewing et al. (1980), 

who monitored gill (Na+-K+) - ATPase 

activity as an indicator of seawater 

readiness, found activity to be lower 

among slower-growing fish; fastergrowing fish had either a more fully 

functional osmoregulatory system or 

lSmolt is a silvery juvenile, tolerant 

of seawater, migrating toward the 

ocean; fry may live in estuaries with 

moderate salinities, but generally do 

not enter the ocean. A parr is a 

pre-smolt stage with vertical bars 

(Parr marks) on the sides. 

6 
one that was capable of faster 

acclimation to higher salinities 

(Wagner et al. 1969). Most investigators agree that the Parr-smolt 

transformation involves an endogenous 

rhythm affected by fish size and 

growth rate and environmental cues 

that include temperature, photoperiod, 

and lunar cycle (Ewing et al. 1979; 

Grau 1981). 

Downstream Migration 

Juvenile chinook salmon form two 

major groups (Gilbert 1913): those 

that migrate to the ocean early in 

their first year of life (ocean-type) 

and those that overwinter in freshwater before entering the ocean 

(stream-type). Fall-run chinook salmon are typically ocean-type and 

emigrate downstream to estuaries as 

fry shortly after they emerge or as 

smolts (Reimers 1973; Kjelson et al. 

1982). Juvenile chinook salmon of the 

spring-run characteristically are 

stream-type and emigrate as yearlings 

in early spring (Schaffter 1980). 

Winter-run chinook salmon fry emerge 

in the summer and emigrate during 

fall, when they are 4 to 7 months old 

(Slater 1963). The periods of peak 

abundance of migrating juvenile chinook salmon in the Sacramento River 

are shown in Figure 3. 

Chinook salmon juveniles usually 

emigrate in the upper 2 m of water in 

daylight, but swim deeper and disperse 

after dark (CDFG 1975; Schaffter 

1980). The larger migrants tend to 

concentrate in midstream where current 

velocities are greatest (Schaffter 

1980). As spring progresses, the 

vertical distribution of emigrants is 

increased as they disperse and inhabit 

deeper water (Wickmire and Stevens 

1971). Increases in streamflow and 

turbidity also have been observed to 

increase the vertical and horizontal 

distribution of migrants (Hallock and 

Van Woert 1959). Fry migrate slower 

than smolts, a characteristic attributable to their preference of slower 

velocity streambank areas or their 

orientation; they face upstream, 

whereas smolts swim downstream 

(Schaffter 1980). Estimates of the 

migration rates of fry and smolts 

average 1.6 km/day in the mainstream 

(Rutter 1904; Wickmire and Stevens 

1971; Kjelson et al. 1982). The time 

of year, water temperature, streamflow, and fish size are all factors 

influencing the time and speed of 

downstream migration. 

Estuarine Residence 

Several early life history patterns of fall-run chinook salmon in a 

coastal Oregon river were reported by 

Reimers (1973). Most fish emigrated 

into the estuary in the spring as fry 

2 to 3 months old (50-69 mm long). 

Some fry entered the ocean in midsummer, but others remained in the 

estuary an additional 2 to 4 months 

and entered the ocean in the fall (90 

to 119 mm long). From scale analysis 

of returning adults, Reimers (1973) 

concluded that the survival of fish 

that remained in the estuary until 

fall was greater than that of migrants 

that left the estuary in mid-summer. 

Other juvenile chinook salmon 

migration patterns, according to 

Reimers (19731, include fish that go 

directly into the ocean from freshwater. Newly emerged fry may directly 

enter the ocean; juveniles (70-85 mm 

long) sometimes pass directly into the 

sea during fall freshets; and yearlings (loo-130 mm long) may enter in 

the spring. 

Two principal movements of 

juvenile fall-run chinook salmon into 

the Sacramento-San Joaquin Estuary 

(the Delta and Suisun, San Pablo, and 

San Francisco Bays) have been 

identified (Kjelson et al. 1982). Fry 

(40-50 mm long) began entering the 

estuary in January and peaked in abundance in February and March; most 

stayed in the upper estuary's freshwater channels (the Delta). A later 

emigration of chinook smolts (80-90 mm 

long) occurred from April to June; the 
fish moved quickly through the Delta 

and Suisun and San Pablo Bays. 

Chinook salmon smolts typically use 

estuaries only as migrational 

corridors to the ocean (Reimers 1973; 

Kjelson et al. 1982; Simenstad 1983), 

whereas fry remain in the estuary 

until they become larger and environmental conditions stimulate them to 

move into the ocean. 

Estimates of chinook fry residence time in northwestern U.S. and 

Canadian estuaries ranged from 10 days 

to 2 months (Shepard 1981). Probable 

factors that affected their length of 

stay in estuaries were fish size, 

population density, prey abundance, 

habitat suitability, freshwater inflow 

(particularly abrupt increases), and 

water temperature (Reimers 1973; 

Shepard 1981; Kjelson et al. 1982; 

Simenstad 1983). 

Chinook salmon fry (30-50 mm 

long) in estuaries characteristically 

feed in schools in littoral or shallow 

sublittoral habitats such as saltmarshes, mudflats, and other intertidal areas. The feeding habits of 

chinook salmon fry are regulated 

largely by the tidal cycle. For example, during flood tide, fry move from 

small tidal channels into near-shore 

marshes (Healey 1980, 1982). Nocturnal onshore movements for feeding have 

also been described for chinook salmon 

fry (Myers 1980; Cannon 1982). Larger 

fry and smolts congregate in surface 

waters of main and subsidiary channels 

and move into shallow sublittoral 

zones to feed. Occasionally they 

enter blind tidal channels, but their 

stay appears to be transitory (Shepard 

1981; Simenstad 1983). The composition of the substrate in estuaries 

inhabited by salmon is commonly mud, 

silt, and sand, and less frequently, 

coarser materials (Forsberg et al. 

1977; Healey 1980). 

The distribution of chinook 

salmon fry in the Sacramento-San 

Joaquin Estuary seemed to be regulated 

by freshwater inflow during the 

downstream migration (Kjelson and 

Raquel 1981). In years of high 

freshwater inflow, the fry inhabited 

both upper freshwater channels (the 

Delta) and the brackish waters of 

Suisun Bay and San Pablo Bay. In 

years of low flow, most of the fry 

were restricted to the upper Delta. 

Spring discharge also affects survival 

of fry in estuaries. High freshwater 

inflow may reduce the mortality of 

chinook salmon fry and smolts caused . 

by high water temperatures, water 

diversion, and predation. 

Sand sills frequently form at 

the mouths of small coastal streams in 

northern California; these cause lower 

tidal movement and salinities than 

those found in larger open estuaries. 

In such a stream, further emigration 

is prevented by the sill and the 

growth and mortality of juveniles are 

affected by the size of the estuary 

and the population density of chinook 

and their predators (Reimers 1973). 

A strong relation between chinook 

salmon abundance and availability of M 

suitable habitat suggests that 

estuarine land "reclamation" may 

substantially reduce the biological 

carrying capacity of the estuary (Levy 

and Northcote 1982). Also, land 

management practices (levees, stream 

channeling and breaking sand sills) 

that reduce estuarine trapping of 

incoming allochthonous materials may 

reduce the detritus-based food web 

believed to be necessary to maintain 

an abundance of juvenile salmon 

(Sibert et al. 1978; Healey 1982). 

Oceanic Residence 

Upon entering the ocean, most of 

the chinook salmon smolts from the 

Sacramento-San Joaquin Estuary migrate 

northward, but a spring fishery for 

chinook salmon south of San Francisco 

Bay at Monterey is evidence that there 

is some southward migration (Snyder 

1931). The extent of northward 

movement fluctuates considerably, 

depending on ocean environme@al 

conditions, food availability, and 

8 
race. For example, in a mark and 

recovery study, over 50% of the 1949 

year-class of fall-run chinook salmon 

from the Sacramento River were caught 

north of the Oregon border, but in a 

following study 90% were caught south 

of there (Jensen 1971). Analyses of 

Pacific coast catch data (sport and 

commercial) suggest that fall-run 

chinook salmon spend most, if not all, 

of their oceanic life near shore, 

relatively close to their home river. 

Spring-run chinook salmon often leave 

nearshore waters in their first year 

of life and seek out more northerly 

high seas areas (Hartt 1980; Healey 

1983). 

Male and female chinook salmon 

usually spawn when they are 3 to 4 

years old. Two-year-old male spawners 

(commonly called "jacks") usually make 

UP 10% to 25% of the spawning run in 

California waters. Yearling male 

chinook salmon may mature before they 

emigrate to the ocean (Rutter 1904; 

Rich 1920). 

Factors that account for the 

return of adult salmonids to their 

natal streams are among the most 

perplexing and least understood facets 

of salmon biology. The consensus of 

salmon biologists is that high seas 

navigation is innately controlled, and 

that the role of extrinsic environmental factors increases in importance 

as the salmon approach their home 

estuary (Brannon 1981). Orientation 

in marine waters is believed to 

involve magnetic and celestial information, interpreted by the innate 

latitudinal and calendar senses of the 

fishes (Brannon 1981; Quinn 1981). 

The length of day, rate of change of 

day length, sun position, and light 

polarization are suggested cues. 

Nearshore migration may be enhanced by 

onshore winds that concentrate river 

water close to shore where olfactory 

cues further guide the salmon (Banks 

1969). 

GROWTH 

Chinook salmon fry newly emerged 

from the redd are 35 to 44 mm long and 

weigh as much as 0.5 g (Rich 1920). 

Fry grew 0.26 to 0.40 mm/day (mean 

0.33 mn/day) in the upper Sacramento 

River, but during the same period, 

0.40 to 0.69 mm/day (mean = 

0.53 mm/day) in the estuary (Kjelson 

et al. 1982). Growth rates generally 

increase in estuaries (Rich 1920; 

Reimers 1973). In more northern 

estuaries, growth ranged from 0.37 to 

1.32 mm/day (Shepard 1981). The rate 

of growth of chinook salmon further 

accelerates when they enter the ocean. 

Fall-run chinook salmon smolts average 

8 cm total length (TL) when they leave 

the Sacramento-San Joaquin Estuary and 

are as long as 30 cm by the end of 

their first year (Jensen 1971). The 

average lengths of chinook salmon of 

different aqes are shown in Table 1. 

The average weights of salmon 

are greatest just before they migrate 

into the river to spawn. They lose 

15% to 20% of their body weight during 

upstream migration in large river 

systems and an additional 10% to 15% 

during spawning (Rutter 1904). 

Table 1. Mean total length (cm) and 

(in parentheses) percent composition 

at each age of fall-run chinook salmon 

in the California commercial troll 

fishery, 1970-72 (from Denega 1973). 

Age in yearsa 

Year 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) 128) (1) 

1972 - 43.2 68.6 81.3 96.5 

(21) (46) (32) (1) 

aLengths at age 1 were derived from 

back calculation of scale. 

9 
THE FISHERY 

The California commercial salmon 

fishery began along the Sacramento 

River in the mid-1800's. By 1881, 20 

canneries were processing over 10 

million pounds of chinook salmon from 

the Sacramento and San Joaquin Rivers. 

Two years later the fishery collapsed, 

presumably as a result of overfishing and the loss of spawning 

habitat from gold mining operations 

(Frey 1971; Jensen 1971). Gill nets 

were the most efficient means of 

catchinq salmon in the rivers, but as 

catches declined in the late 1800's, 

some fishermen began trolling in offshore waters. The California ocean 

troll fishery began near Monterey in 

the 1880's and near Eureka and 

Crescent City in 1916 (Frey 1971). 

Chinook salmon caught in the ocean 

constituted an increasing proportion 

of the commercial salmon catch because 

the major northern California rivers 

were closed to commercial salmon 

fishing from 1919 to 1933. The 

commercial salmon fisheries in the 

Sacramento and San Joaquin Rivers 

closed in 1957. Annual chinook salmon 

catches in California were highest in 

1918-19 and 1945-46 (over 13 million 

pounds each year); record low landings 

of less than 4 million pounds were 

reported for 1938-39, 1941, 1958 and 

1983. A summary of the annual 

California ocean sport and commercial 

troll catches for selected years from 

1940 to 1983 is shown in Table 2. 

All of the commercial salmon now 

landed in California waters are 

caught by ocean trolling. Annually, 

an average of 4,800 salmon trolling 

boats expended 75,000 fishing days 

from 1978 to 1983 (PFMC 1984). Sportfishirq in the ocean has flourished 

since World War II and now contributes 

about 21% of the California catch. The 

ocean sport fishery in California 

supported an average of 193,000 angler 

trips annually between 1971 and 1983 

(PFMC 1984). 

Table 2. The number of chinook salmon 

in the sport fishery and the weight 

and value (all in thousands) of 

chinook salmon in the commercial 

fisheries of California, 1940-83 

(data from National Marine Fisheries 

Service 1940-75 and Pacific Fishery 

Management Council 1984). 

Sport fishery Commercial 

Year Numbers Pounds Dollars 

1940 

1945 

1950 

1955 

1960 

1965 

1970 

1975 

1980 

1983 

7a 

_- 

56a 

12ga 

38a 

60 

148 

104 

86 

62 

5,156a 411 

7,912 1,446 

5,861 1,572 

9,317 3,266 

5,996 3,242 

7,397 4,132 

5,266 4,421 

5,781 6,123 

5,907 13,149 

2,308 4,609 

aMay include some coho salmon. 

The Sacramento River and several 

other northern coastal rivers in 

California support a substantial sport 

fishery for chinook salmon. From 1977 

to 1981, the average sport catch of 

fall-run chinook salmon in the 

Sacramento River was 1.8% of the 

total estimated run (Hoopaugh and 

Knutson 1979; Knutson 1980; Reavis 

1981a, 1981b, 1983). The sport catch 

of the remaining three stocks averaged 

1.8% of the late fall run, 1.7% of the 

winter run, and 2.5% of the spring 

run. The salmon sport fishery in the 

Klamath River is estimated to compose 

up to 13% of the total chinook salmon 

run and 7% of the total ocean sport 

and commercial catches of Klamath 

River fish (U.S. Fish and Wildlife 

Service 1980, 1981, 1982, 1983, 1984). 

The economic value of the 

Pacific coast salmon fishery is of 

great importance, ranking second in 

quantity and value in the entire 1983 

10 
U.S. marine catch (NMFS 1984). The 

estimated value of California's 

commercial chinook salmon fishery is 

shown in Table 2. The dollar value of 

commercial salmon depends on fish size 

and dockside ex-vessel price (Wahle et 

al. 1974). In 1983, ex-vessel prices 

per pound ranged from $1.40 for small 

salmon less than &lb to $2.25 for 

fish lerger than 12 lb (PFMC 

1984). The exact value of the ocean 

sport salmon fishery is difficult to 

ascertain, but an estimate of the net 

economic sport value of a chinook 

salmon is $63.00 per fish. Chinook 

salmon caught in rivers are estimated 

to be worth $28.00 per fish (Mathews 

and Brown 1970). 

According to Wright (19811, the 

salmon fishery needs to be regulated 

for optimum yield. He suggested that 

optimum yield may be reached by using 

area and season closures, minimum size 

limits, and gear restrictions. A more 

k 

direct method would be through the 

establishment of limited entry or 

catch quotas. Catch quotas halve been 

instituted in Oregon and Washington, 

and recently the California legislature has joined Oregon and Washington 

in an attempt to limit the entry of 

new fishing boats into the existing 

fleet (PFMC 1984). 

The magnitude of the chinook 

salmon fishery has probably 

contributed to the decline * 

abundance of the species. Rick:: 

(1980, 1981) attributed the apparent 

decrease in size and age at maturity 

of chinook salmon stocks to the huge 

salmon catch in the commercial troll 

fishery along the Pacific coast. 

Since the 1920's, the average weight 

of troll-caught chinook has decreased 

significantly (some 2.5 kg in British 

Columbia waters from 1951 to 19751, 

and mean age at maturity for returning 

adults has decreased from 4 years to 3 

years. Ricker (1980) stated that 

trends in ocean temperatures are not 

known to be responsible for the age 

and size decreases, but offers several 

other possible explanations: 

11 

1. 

2. 

3. 

The increased intensity of the 

troll fishery has resulted in 

more salmon being caught early in 

the season and at a smaller size. 

The ocean catch has been so large 

that fewer salmon survive to 

older ages and young fish make up 

a bulk of the catch (i.e., the 

"fishing-up effect"). 

The excessive removal of latematuring salmon favors reproduction of smaller, early-maturing 

fish. 

The increased proportion of younger 

fish in the spawning population had 

been recognized earlier by Warner et 

al. (1961) for the Sacramento River 

and by Junge and Phinney (1963) for 

the Columbia River. 

Current California stocks of 

chinook salmon are heavily 

supplemented by hatchery fish that are 

released as fry or fingerlings (large 

fry to yearlings). Now being evaluated are the survival of hatcheryreared salmon and their contribution 

to the offshore fishery, returns to 

the hatchery in relation to fish size 

at the time of release and the 

distance from the point of release to 

the ocean (Sholes and Hallock 1979;. 

Kjelson et al. 1982). Production ot 

chinook salmon (State and Federal 

hatcheries) in California from 1971 to 

1981 is shown in Table 3. 

ECOLOGICAL ROLE 

Competition 

Competition for spawning gravels 

between chinook salmon and other 

anadromous species is limited because 

of the chinook salmon's preference for 

spawning grounds in mainstem or large 

tributary streams and their early 

period of upstream migration and 

spawning. Downstream disperson of 

newly emerged salmonid fry is a 

density adjustment mechanism and may 
Table 3. The numbers (thousands) and 

weight (thousands of pounds) of 

juvenile fall-run chinook salmon 

raised in State and Federal hatcheries 

and released in California rivers from 

1971 to 1981 (data from California 

Department of Fish and Game 1972-84 

and U.S. Fish and Wildlife Service 

1970-81). 

State Federal 

Year Number Weight Number Weiglht 

1971 37,845 413 8,186 118 

1972 28,793 446 12,360 115 

1973 23,384 452 10,971 114 

1974 15,115 371 12,518 113 

19756 24,9477039 45643 8,544 72051:: 

1977 24,723 535 10,129 116 

1978 14,598 335 8,719 

1979 16,187 555 7,411a 

84 

117" 

1980 20,133 677 16,951 229 

1981 34,850 650 16,060 138 

-- 

'Includes some winter-run chinook 

salmon. 

result in cohabitation of chinook 

salmon fry with juvenile steelhead 

trout or coho salmon (Reimers 1973). 

Juvenile chinook salmon, like other 

stream-dwelling salmonids, are. 

territorial, and competition for food 

and space may result when they live in 

the same waters with other salmonids. 

Fry of chinook salmon and coho salmon 

select similar habitat, and coho 

salmon are the more aggressive of the 

two species (Lister and Genoe 1970; 

Stein et al. 1972). The aggression 

and territoriality of salmon fry 

appear to be influenced by current 

velocity, and are subdued in large 

pools and estuaries where schooling 

is common (Reimers 1968). I ntraspecific dominance is largely governed 

by fish size (Chapman 1962; Reimers 

1968). 

The early downstream migration 

of ocean-type chinook salmon fry 

reduces contact with other species, 

but large introductions of hatcheryreared coho salmon may encourage 

premature emigration of chinook salmon 

fry from freshwater into estuarine or 

oceanic waters and could reduce growth 

and survival of the chinook salmon 

migrants (Stein et al. 1972). Myers 

(1980) reported a large degree of 

feeding overlap in estuaries between 

wild chinook juveniles and hatcheryreleased coho salmon and hypothesized 

a high potential for competition. 

Stream-type chinook salmon live in 

freshwater for up to a year and 

frequently occur with juvenile 

steelhead trout. The selection of 

different habitats by the two species 

reduces competition for space or food 

(Everest and Chapman 1972). 

Upon entering the estuary, 

chinook salmon fry and smolts are 

confronted with a sizable assemblage 

of potential competitors. High 

population densities of chinook salmon 

within estuaries increase intraspecific competition and may result in 

reduced summer growth and early ocean 

entry (Reimers 1973). Shepherd (1981) 

reported that fishes in estuaries 

known to eat the same food as that 

preferred by chinook salmon are coho 

salmon, chum salmon (0. m), pink 

salmon 

trout, cutthroat trout Salmo clarki), 

(0. gorbuscha(), steelhead 

Dolly Varden (Salvilinus malma), 

threespine sticklebacksterosteus 

potential competitors in the Sacramento-San Joaquin Delta are juvenile 

Sacramento squawfish 

grandis) and Delta 

transpacificus) 

The greatest competitors of 

chinook salmon in the ocean are 

probably other Pacific salmon, 

particularly during peak abundance in 

nearshore waters. Evidence of marine 

12 
density-dependent survival was noted 

by Peterman (1978) for northern 

Pacific salmon stocks, but the ocean 

proper probably does not seriously 

limit salmon production (Walters et 

al. 1978). Analysis of food resources 

of the northern Pacific Ocean suggests 

that the supply of food for salmon is 

nonlimiting (Rothschild 1972). 

Predation ~- 

Predation on salmon eggs usually 

is not a major cause of mortality 

because the eggs are in the substrate. 

Predation on chinook salmon fry may be 

high when they begin their downstream 

migration. When salmon are concentrated above or below dams or water 

diversion structures, some are easy 

prey to piscivorous birds such as 

belted kingfishers (Ceryle alcyon), 

herons (Ardeidae), and mergansers 

(Mergus spp.1, and larger salmonids, 

sculpins, Sacramento squawfish, and 

striped bass (Morone saxatilis). 

Hatchery-released fingerling chinook 

salmon and steelhead trout in 

Sacramento River tributaries prey 

heavily on the smaller wild chinook 

salmon fry (Sholes and Hallock 1979; 

Menchen 1981). 

Predation by larger salmonids on 

chinook salmon fry and smolts may be 

substantial in estuaries. Coho salmon 

smolts are known to be highly 

piscivorous during outmigration 

(Parker 1968), and predation by coho 

salmon and other predators may 

significantly reduce survival of 

hatchery-released salmon fry or smolts 

(Peterman and Gatto 1978). Other 

estuarine predators include mergansers, cormorants (Phalacrocorax spp.), 

grebes (Podicipedidae), loons (Gavia 

SPP. ), and ospreys (Pandion 

haliaetus). 

The extent of high seas 

predation is unknown, but loss of 

salmon to northern fur seals 

(Callorhinus spp.) may range from 2 

million to 60 million salmon annually 

(Peterman 1978). The salmon shark 

(La-a~ ditropis) is another high-seas 

predator. Nearshore predators are 

cormorants, osorevs. sea lions 

(Eumetopias jubatu; -and Zalophus 

californianusX, harbor seals (Phoca 

vitulina), blue sharks (PriGc< 

glauca), and lampreys (Lampetra spp.). -- 

Food 

Chinook salmon tend to be more 

opportunistic feeders than other 

salmonids (Healey 1982). Fry in 

streams feed extensively on drift 

insects (Rutter 1904), but zooplankton 

are more heavily eaten in main river 

systems and estuaries. Adult and 

juvenile dipteran insects and 

crustacean zooplankters -- especially 

Cladocera and Copepoda -- are principal food items of chinook fry in the 

Sacramento River and the SacramentoSan Joaquin Estuary (Figure 5). 

Smolts feed on gammarid amphipods and 

larval fish in brackish waters; larger 

and older smolts select larger 

crustaceans (Corophium and Neomysis) 

and fish as food (Cannon 1982). The 

shift from shallow epibenthic prey to 

larger, often pelagic species reflects 

the movement of juveniles from shallow 

littoral habitats into deeper river 

and tidal channels as they increase in 

size. Food consumed by marine 

dwelling juveniles consists primarily 

of fish, crustaceans, and insects 

(Snyder 1924). Marine prey of adult 

chinook salmon are pelagic crustaceans 

such as krill (euphausiids), larval 

crabs, and fish (Figure 5). 

ENVIRONMENTAL REQUIREMENTS 

TemperaChinook salmon are coldwater 

fish but they are more tolerant of 

higher water temperatures than other 

Pacific salmon (Brett 1952). Optimum, 

tolerable, and lethal water temperatures for different life stages of 

chinook salmon are given in Table 4. 

Excessively abrupt water temperature 

changes may kill fish even within 

13 
American R. n=245(35-104rrlCn) 

%Number (Barnhart and Giebink 1983) 

Socromento-Son Jw uin Delto 

n=540 (< 70mm) o 1 Number 

(K-01 1982) 

CA Coast n= 1004 043-104lmm) 

%Volume (Merkel 1957) 

Figure 5. Stomach contents of 

chinook salmon of different 

lengths (in parentheses) and 

habitats. 

tolerated ranges. In the Deltg, water 

temperatures that exceed 23 C are 

lethal to most chinook smolts (Kjelson 

et al. 1982). 

Salinity 

Among the Pacific salmons, juvenile chinook salmon are most tolerant 

of changing salinities. Shortly after 

hatching, the alevins tolerate moderate salinities (15 ppt), and at 100 

days of aqe and at a mean length of 

65 mm, they tolerate full-strength 

seawater (Wagner et al. 1969). Salinity tolerance can be broadened by 

acclimation and is increased by the 

size of the fish and rate of growth. 

Despite a high tolerance for high 

salinities, studies in the SacramentoSan Joaquin Estuary and in southern 

Canadian estuaries suggested an apparent preference of low salinity water 

by chinook salmon fry (Healey 1982; 

Kjelson et al. 1982). The salinity 

requirements of juvenile chinook salmon are listed in Table 4. Adult 

salmon tolerate rapid salinity 

changes. 

Dissolved Oxyqen 

The dissolved oxygen (DO) 

requirements of chinook salmon embryos 

are unclear, but Alderdice et al. 

(1958) observed an increase in oxygen 

demand by chum salmon embryos as they 

neared hatching. The effects of DO 

concentrations below the saturation 

level on salmonids include delayed or 

premature hatching (depending on the 

timing of low DO in the 

development process); abnormal ernb:;! 

development; reduced size and strength 

at hatching; reduced growth, feeding, 

and swimming ability; and increased 

susceptability to disease, predation, 

and toxic contaminants (Orsi 1967; 

Davis 1975). The DO requirements of 

chinook salmon may change at various 

life stages (Table 4). 

14 
Table 4. Temperature, salinity, and dissolved oxygen requirements for several 

life stages of chinook salmon, 

- 

Environmental Limits 

factor Life stage Optimal Tolerance Lethal Comments 

Tgmperature Adult 10.6-19.4a 

( Cl upstream 3.3-13.3a 

migration 

Spawning 

Egg 

incubation 

5.6-13.9b 

5.8-14.2' < 0.6' 

Juvenile 12-13e 

rearing 

Salinity Juvenile 

(PPt) rearing 

Dissolved 

oxygen 

(mg/l) 

Adult 

upstream 

migration 

Egg Saturation 

incubation 

>5.0b 

Juvenile 

rearing 

>4.5h 

>3.0h 

< 0.8e 

>25.1e 

>15f 

>30f 

< 1.6g 

Fall-run chinook 

Spring-run chinook 

Eggs survive near 

freezing after 

initial development to 128 ctll 

stage at 5OC. 

Acclimated at 10°C 

Acclimated at 24'C 

At 10 days posthatch 

At yolk-sac absorption (with 

acclimation) or 

at 100 days post 

hatch (without 

acclimation) 

As percent saturation decreases, 

growth decreases 

and abnormalities 

and mortality 

increase. 

Avoidance at 16- 

25°C. 

Avoidance at 8- 

18°C. 

aBell (1973). 

bReiser and Bjornn (1979). 

eBrett (1952). 

iCombs and Burrows (1957). 

fWagner et al. (i969). 

gSilver et al. (1963). 

Piper et al. (1982). hWhitmore et al. (1960). 

15 
Substrate 

Substrate requirements are 

fairly rigid for successful spawning 

and egg incubation. Chinook salmon 

spawn over a substrate of 

unconsolidated materials of the 

appropriate size and adequate 

intragravel water flow, with proper 

stream depth, current velocity, and 

bottom contour. The requirements for 

spawning and rearing of chinook salmon 

are described in Table 5. Chinook 

salmon fry tend to prefer soft 

substrates, possibly because of the 

preferred low water velocities there, 

but fry also inhabit areas of gravel, 

cobble, or bedrock in either streams 

or estuaries (Everest and Chapman 

1972; Healey 1980). Juvenile springrun salmon that overwinter in streams 

are known to seek coarse substrates 

(cobble or boulder) for protection 

against heavy winter and spring flows 

(Chapman and Bjornn 1969). 

The greatest threat to the 

substrate quality is the accumulation 

of fine sediments on spawning gravels 

and food-producing areas (Cordone and 

Kelley 1961). Excessive sedimentation 

clogs gravel interstices and reduces 

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

Environmental Limits 

factor Life stage Optimal Tolerance Comments 

Substrate size Spawninga 

(cm) 

1.3-10.2 

Juvenile 

rearingb 

silt 

Depth (m)C Adult upstream 

migration 

Spawning > 0.24 

Juvenile 

rearing 

0.3-1.22 

Water 

velocity 

(m/s) 

Adult upstream 

migration 

SpawningC 

Juvenile 

rearingC 

siltrubble 

2 0.24 

0.3-0.91 

0.06-0.24 

5 2.4' 

< 6.1d - 

80% 1.3-5.1 cm, 

20%>5.1 cm 

Sustained current 

maximum 

Obstacle current 

maximum 

90%-95% confidence 

interval 

aBell (1973). 

bEverest and Chapman (1972). 

'Thompson (1972). 

dWeaver (1963). 

16 
L 

intragravel water flow, which is is greater (Everest and Chapman 1972). 

essential for the transport of oxygen Current velocity preferences for 

to, and metabolic wastes from, incu- spawners and juveniles are given in 

bating egg surfaces. Heavy sedimen- Table 5. The cruising, sustained, and 

tation may also trap alevins in the darting speeds of adult chinook salmon 

gravel, causing suffocation or star- are about 1.1, 3.3, and 6.8 m/s, 

vation. Sedimentation of rocky sub- respectively (Bell 1973). Maximum 

strates also reduces the available speeds depend on fish size, water 

habitat for food organisms and reduces temperature, dissolved oxygen concenfish escape cover. trations, and stage of maturity. 

R&h The estimation of streamflow 

Minimum depths are necessary to 

assure successful upstream migration 

of adult salmon. During low flow, 

riffles may be too shallow for adult 

passage. Thompson (1972) developed 

methods by which critical areas are 

identified and adequate passage flows 

are estimated. Depth is important in 

spawning site selection because it 

affects the hydraulic "head" and 

intragravel flow. Chinook salmon are 

reported to spawn at depths up to 10 m 

in large rivers (Chapman 19431, but 

generally favor depths less than 3 m. 

Depth criteria for migrating and 

spawning chinook are listed in 

Table 5. Depth preference of streamdwelling juvenile chinook salmon is 

about 1 m and may be influenced by 

water velocity, instream cover, fish 

size, and the abundance of predators 

and competitors. Chinook salmon fry 

and smolts in estuaries favor surface 

waters in shallow flats or deepwater 

channels. 

Water Movement 

Adequate current velocities are 

required to assist the female in nest 

excavation and for intra-gravel flow. 

Gangmark and Bakkala (1960) found 

significant increases in mortality of 

chinook salmon eggs when intragravel 

flow rates dropped below 60 cm/h. 

Juvenile chinook salmon in streams and 

estuaries select low velocity 

habitats, but in streams the fry will 

seek faster waters as they grow larger 

and most select locations adjacent to 

higher velocities where prey abundance 

requirements for juvenile salmonids is 

extremely complex due to the interaction of numerous physical, chemical, 

and biological factors. The Instream 

Flow Incremental Methodology (IFIM) 

was developed by the USFWS Cooperative 

Instream Flow Service Group to predict 

the effects of a decline in flow and 

space on freshwater fish populations 

(Bovee 1982). This procedure, a 

hydraulic simulation model that incorporates fish age and species-specific 

habitat preference data, is in use 

throughout the western United States. 

Flow requirements for chinook salmon 

in large rivers are complex, but 

several studies have associated high 

survival of downstream migrants with 

high discharges in the spring 

(Wetherall 1970; CDFG 1975; Kjelson 

and Raquel 1981; Kjelson et al. 1982). 

Survival of chinook salmon smolts in 

the Sacramento River was highly 

correlated (r = .94) with freshwater 

inflow in the spring and estuarine 

water temperatures (Kjelson et al. 

1982). Various data support the view 

that years of high freshwater inflow 

in the San Joaquin River result in 

greater return of spawning adults 

2.5 years later (CDFG 1975; Kjelson 

and Raquel 1981). 

rurbidity 

Juvenile salmonids are capable 

of tolerating turbidity as high as 

1,000 ppm, but reductions of primary 

food production and feeding 

efficiency are likely at much lower 

turbidities (Bell 1973). The migration of adult salmon may be inhibited 

at turbidities of 4,000 ppm (Bell 

17 
1973), and chinook salmon are reported 

to avoid turbid waters if given a 

choice (Cordone and Kelley 1961). 

Direct harm to fish by excessive 

suspended sediments is probably rare 

nature and can be combatted in 

ia"rt by mucous secretions that flush 

gill membranes. Abrasion and clogging 

of gill lamellae may result under 

extreme turbidities and are related to 

the size and hardness of the suspended 

material (Cordone and Kelley 1961). 

Prolonged exposure to highly turbid 

waters may cause thickening of gill 

lamellae, which reduces oxygen-carbon 

dioxide exchange efficiency resulting 

in an increase in vulnerability to 

disease (Bell 1973). Silt deposits 

are more damaging to salmon than silt 

suspended in the water column. 

Heavy Metals 

Acid-mine wastes from the Spring 

Creek drainage have caused numerous 

kills of chinook salmon, steelhead 

trout, and other species in the 

Sacramento River between Keswick Dam 

and Cottonwood Creek (a distance of 33 

river mi) (USFWS 1959; Prokopovich 

1965; Nordstrom 1977). Of the four 

most abundant metals in the mine 

waste, copper and zinc are extremely 

toxic to chinook salmon. Since 1963, 

the wastes have been collected in 

Spring Creek Reservoir and metered into 

Keswick Reservoir at levels thouqht to 

be safe for anadromous fish (Finlayson 

and Ashuckian 1979). In 1978, new 

interim release schedules proposed by 

Wilson (1978) allow for maximum dissolved copper and zinc concentrations 

of 5 pg/l and 64 pg/l, respectively 

(Finlayson and Verrue 1980). Recently 

the water quality program to partially 

control metal concentrations in the 

Sacramento River (from acid-mine 

wastes from Spring Creek) has 

curtailed the number of fish kills 

(Wilson et al. 1981). The sublethal 

effects on chinook salmon and other 

fish species caused by chronic exposure to the metals are not known. 

. 

18 
Alderdice, D.F., W.P. Wickett, and 

J.R. Brett. 1958. Some effects of 

temporary exposure to low dissolved 

oxygen levels on Pacific salmon 

eggs. J. Fish. Res. Board Can. 

15:229-250. 

Instream Flow Inf. Pap. No. 12. 

FWS/OBS-82/26. 248 pp. 

Barns, R.A. 1969. Adaptations of 

sockeye salmon associated with 

incubation in stream gravels. Pages 

71-87 ’ T.G 

Symposiu? on 

Northcote ed 

sa'lmon and trbut in 

streams. H.R. MacMillan Lectures in 

Fisheries, University of British 

Columbia, Vancouver. 

Brannon, E.L. 1981. Orientation 

mechanisms of homing salmonids. 

Pages 217-219 b E.L. Brannon and 

E.O. Salo, eds. Salmon and trout 

migratory behavior symposium. University of Washington, Seattle. 

Brett, J.R. 1952. Temperature tolerance in younq Pacific salmon. aenus 

Oncorhynchus.- J. Fish. Res: Board 

Can. 9:265-323. 

Barns, R.A. 1976. Survival and 

propensity for homing as effected by 

presence or absence of locally 

adapted paternal genes in two 

transplanted populations of pink 

salmon CQ. qorbuschal. J. Fish. 

Res. Board Can. 33:27i6-2725. 

Briggs, J.C. 1953. The behavior and 

reproduction of salmonid fishes in 

a small coastal stream. Calif. Fish 

Game Fish Bull. No. 94. 62 PP. 

Burner, C.J. 1951. Characteristics of 

spawning redds of Columbia River 

salmon. U.S. Fish Wildl. Serv. Fish. 

Bull. 52(611:97-110. 

Banks, J.W. 1969. A review of the 

literature on the upstream migration 

of adult salmonids. J. Fish Biol. 

1:85-136. 

Barnhart, R.A., and J.G. Giebink. 

1983. Food habits of juvenile 

chinook salmon in the lower American 

River from March 11, 1983 to June 7, 

1983. Calif. Coop. Fish. Res. Unit, 

unpubl. rep. 20 pp. 

California Department of Fish and 

Game. 1971. An assessment of 

Federal water projects adversely 

affecting California salmon and 

steelhead resources. II. Friant 

Dam. California Department of Fish 

and Game, Sacramento. 11 PP. 

Bell, M.C. 1973. Fisheries handbook 

of engineering requirements and biological criteria. U.S. Army Corps 

of Engineers, North Pacific Division 

Contract No. DACW57-68-C-0086. 

California Department of Fish and 

Game. 1972-84. California trout, 

salmon,. and warmwater fish production and costs. Calif. Dep. Fish 

Game, 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 stream California Department of Fish and 

habitat analysis using the instream Game. 1975. Interagency ecological 

flow incremental methodology. study program for the Sacramento-San 

LITERATURE CITED 

19 
Joaquin Estuary. 4th Annu. Rep. 

1974. 121 pp. 

Cannon, T.C. 1982. The importance of 

the Sacramento-San Joaquin Estuary 

as a nursery area of young chinook 

salmon, striped bass, and other 

fishes. Rep. to Natl. Mar. Fish. 

Serv. Southwest Region. 102 pp. 

Chapman, D.W. 1962. Aggressive 

behavior in juvenile coho salmon as 

a cause of emigration. J. Fish. 

Res. Board Can. 19:1047-1080. 

Chapman, D.W., and T.C, Bjornn. 1969. 

Distribution of salmonids in 

streams, with special reference to 

food and feeding. Pages 153-176 in 

T.G. Northcote, ed. Symposium 3 

salmon and trout in streams. H.R. 

MacMillan Lectures in Fisheries, 

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20 
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26 
i 

0::: .‘01 

_ ^ 

r&-OAT S.DCL’ME!iTATION 1. @tmRT no. 2. 

PAGE I Biological Report 82(11.49)*! 

Life Histories and Environmental 

ery Research Unit 

II. bw8ctlcI w crmni(G) NO. 

Arcata, CA 95521 

National Coastal Ecosystems Team U.S. Army Corps of Engineers 1% TYmdR*pon L Cwmd cewrnl 

Fish and Wildlife Service Waterways Experiment Station 

U.S. Department of the Interior P.O. Box 631 

Washington, DC 20240 Vicksburg, MS 39180 

t 

14. 

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

16. Abansr Nrnit 2m rords, 

Species profiles are literature summaries of the taxonomy, morphology, distribution, 

abundance, life history, and environmental requirements of coastal aquatic species. They 

are prepared to assist in environmental impact assessment. The chinook salmon 

(Oncorhynchus tshawytscha) is a valuable sport and commercial fish species and accounted 

for 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 chinook 

salmon in California, are divided into fall, late fall, winter, and spring runs. Other. 

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. Some 

fry migrate immediately to saltwater, others remain 2 to 12 months in freshwater bqfore 

migrating. They remain in the ocean from 1 to 7 years; most females mature and return to 

freshwater to spawn after 2 to 4 years at sea. Some males return to spawn after on?y 

1 year in the ocean, but most return after 2 to 4 years. All chinook salmon die after 

they reenter freshwater, whether they spawn or not. 

Fishes Estuaries 

Growth Animal migrations 

L. I4mnclfi~n/ovan4hl*d Term. 

Habitat requirements 

Life history 

Chinook salmon 

Oncorhynchus tshawytscha 

Salinity requirements 

Temperature requirements 

Unlimited release 

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

Species proiiies : 

Ailen, ilark A. 

Test wch Library 

dJJ. S. Department of the Interin-, 

Vational Biological Survey 

wthern Science Center 

00 Cajundome Boulevard 

_f >.. &j....> c, :’ “.r, 7fl5nfi ‘: ; M 

Headquarters. Division of BiOlOgiCal 

Services, Washington, DC 

Eastern Energy and Land U.ae Team 

Leetown. WV 

National Coastal Ecosystems Team 

Slidell. LA 

Western Energy and Land Use Team 

Ft. Collins, CO 

Locations 01 Regional Offices 

REGION 1 

Regional Director 

U.S. Fish and Wildlife Service 

Lloyd Five Hundred Building, Suite 1692 

500 N.E. hlultnomah Street 

Portland, Oregon 97232 

REGION 2 REGION 3 

Regional Director Regional Director 

U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service 

P.O. Box 1306 Federal Building, Fort Snelling 

Albuquerque, New Mexico 87 103 Twin Cities, Minnesota 55 I 11 

REGION 5 

Regional Director 

U.S. Fish and Wildlife Service 

One Gateway Center 

Newton Corner, Massachusetts 02 I58 

REGION 6 

Regional Director 

U.S. Fish and Wildlife Service 

P.O. Box 25486 

Denver Federal Center 

Denver, Colorado 80225 

REGION 4 

Regional Director 

U.S. Fish and Wildlife Service 

Richard B. Russell Building 

75 Spring Street, S.W. 

Atlanta, Georgia 30303 

REGION 7 

Regional Director 

U.S. Fish and Wildlife Service 

101 I E. Tudor Road 

Anchorage, Alaska 99503 
DEPARTMENT OF THE INTERIOR 

U.S. HSH AND WllDLlFE SERVlCE 

As the Nation’s principal conservation agency, the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources. This includes 

fostering the wisest use of our land and water resources, protecting our flsh and wildlife, 

preserving thsenvironmental and cultural values of our national parks and historical places, 

and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in 

the best interests of all our people. The Department also has a major responsibility for 

American Indian reservation communities and for people who live in island territories under 

U.S. administration.