(DRAFT) - Taxonomy
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
TAXONOMY
NAME - salmon, chinook
OTHER COMMON NAMES - king salmon, tyee, spring, blackmouth, spring salmon, tule and quinnat
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata,
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Salmoniformes,
FAMILY AND SUBFAMILY - Salmonidae,
GENUS AND SUBGENUS - Oncorhynchus,
SPECIES AND SSP - tshawytscha,
SCIENTIFIC NAME - Oncorhynchus tshawytscha
AUTHORITY - Walbaum
TAXONOMY REFERENCES - 89 and 232
COMMENTS ON TAXONOMY -
Other common names include king salmon, tyee, spring, and blackmouth *11*.
Common names include king salmon, spring salmon, tyee, tule, quinnat, and
blackmouth *232*.
Caution must be used when extending information from one stock of chinook
salmon to another stock. Environmental conditions for one area must not be
treated as absolute; the stocks (races) have acclimated or evolved over time
and space to habitat conditions that can vary greatly *232*.
Taxonomy - 1 (DRAFT) - Status
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
STATUS
Coded Status
T: Federal Threatened
Sport Fish
Commercial
Commercial/consumption
Migrant
Existing, FMP exists
See Comments
REFERENCES FOR STATUS - 89, 232 and 274
COMMENTS ON STATUS -
Chinook salmon represent an extremely important component of both the
commercial and sport fisheries of the Pacific Northwest. Charter boat
fisheries exist along the Pacific coast from San Francisco to Alaska.
Chinook and coho salmon support extensive troll fisheries over the same
latitudes, but trollers additionally fish well out into the Fishery
Conservation Zone (3-200 mi offshore).
Catch statistics indicate a decline in the commercial catch of chinook
salmon over time. Despite this decline, inflation more than tripled the
value of the catch between 1970 and 1980. Although chinook salmon represent
only 9% to 13% of the total commercial salmon catch, they are the most
important in terms of market value and preference. Troll-caught fresh or
fresh-frozen chinook salmon in the 11-18 lb size range are the most highly
preferred salmon by market buyers. Among the Pacific states and Provinces,
British Columbia contributed the largest percentage (27%) of the chinook
commercial and sport catch for the years 1953-1957 *89*.
Chinook salmon are migratory *232*.
MANAGERIAL AUTHORITY:
The Alaska Board of Fisheries develops regulations governing the commercial,
sport, and subsistence harvest of salmon in Alaska. The Alaska Department
of Fish and Game manages salmon populations in the fresh waters of the state
and the marine waters to the 3-mi limit *232*.
The North Pacific Fishery Management Council is composed of 15 members, 11
voting and 4 nonvoting members. The 11 are divided as follows: 5 from
Alaska, 3 from Washington, 3 from state fishery agencies (Alaska,
Washington, Oregon). The four nonvoting members include the director of the
Pacific Marine Fisheries Commission; the director of the U.S. Fish and
Wildlife Service; the commander, 17th Coast Guard District; and a
representative from the U.S. Department of State. The council prepares
fishery management plans, which become federal law and apply to marine areas
between the 3-mi limit and the 200-mi limit. With regard to salmon, the
only plan prepared to date is the Salmon Power Troll Fishery Management Plan
*232*.
The International North Pacific Fisheries commission (INPFC), a convention
Status - 1 (DRAFT) - Status
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
comprised of Canada, Japan, and the United States, has been established to
provide for scientific studies and for coordinating the collection,
exchanges, and analysis of scientific data regarding anadromous species.
With regard to salmon, the INPFC has also prepared conservation measures
that limit the location, time, and number of fishing days that designated
high seas (beyond the 200-mi limit) areas may fished by Japanese nationals
and fishing vessels *232*.
Status - 2 (DRAFT) - Distribution
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
REFERENCES FOR HABITAT - 89
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Estuarine UB1 L 0
Estuarine UB2 L 0
Estuarine UB3 L 0
Estuarine UB4 L 0
Estuarine UB. L 9
Marine V 1
Marine V 1
Riverine SB1 H 0
Riverine RB2 H 0
Riverine SB3 N 1
Riverine, upper perennial SB1 H 0
REFERENCES FOR NWI - 89
Habitat Associations - 1 (DRAFT) - Food Habits
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 89 and 232
LIFESTAGE FOOD FOOD PART
Larva Microorganisms See Comments
Juvenile Copepods Not Specified
Juvenile Insects Not Specified
Adult Osteichthyes Not Specified
Adult Clupeiformes Not Specified
Juvenile Osteichthyes Larva stage
Adult Copepods Not Specified
Adult Insects Not Specified
Juvenile Plankton Not Specified
Juvenile Insects: aquatic Larva stage
Juvenile Insects:terrestrial Not Specified
Juvenile Salmoniformes Egg/Fetus stage
Juvenile Arachnids Not Specified
Juvenile Invertebrate Cordates Not Specified
Juvenile Diptera Larva stage
Juvenile Diptera Pupa stage
Juvenile Diptera Adult stage
Juvenile Crustaceans Larva stage
Juvenile Malacostraca Larva stage
Juvenile Malacostraca Not Specified
Juvenile Copepods Not Specified
Juvenile Crustaceans Not Specified
Juvenile Branchiopods Not Specified
Juvenile Cirripeds Not Specified
Juvenile Osteichthyes Not Specified
Juvenile Perciformes Not Specified
Juvenile Clupeiformes Not Specified
Adult Osteichthyes Not Specified
Adult Crustaceans Not Specified
Adult Malacostraca Not Specified
Adult Molluscs Not Specified
Adult Squid, Octopus Not Specified
Adult Malacostraca Not Specified
Adult Malacostraca Larva stage
Adult Osteichthyes Not Specified
Adult Clupeiformes Not Specified
Adult Perciformes Not Specified
General Crustaceans Not Specified
General Malacostraca Not Specified
Juvenile See Comments; Food See Comments
Adult See Comments; Food See Comments
General See Comments; Food See Comments
REFERENCES FOR GENERAL FOOD - 89 and 232
Food Habits - 1 (DRAFT) - Food Habits
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
REFERENCES FOR IMPORTANT FOOD - 89
REFERENCES FOR ADULT FOOD - 89 and 232
REFERENCES FOR JUVENILE FOOD - 89 and 232
REFERENCES FOR LARVAE FOOD - 89
COMMENTS ON FOOD -
Chinook salmon primarily eat fish, except during the spring when
invertebrates (especially euphausids) are extremely abundant. In late
winter and early spring off San Francisco, chinook feed on herring,
rockfish, other fish, crab megalops, and squid. Euphausids and squid, and
later, herring, crab megalops, and rockfish comprise the spring diet. In
late spring through summer, rockfish dominate the diet, distantly followed
by other fishes and some invertebrates. Anchovies are the dominant diet
item for the remainder of the year. Chinook salmon frequent the waters of
southeast Alaska throughout the year and feed heavily on herring, smelt, and
eulachon. During the winter they move deeper and feed on halibut, rockfish,
cod, and octopi *89*.
Types of Feeding Areas Used: Juveniles feed in low-velocity areas of
streams and rivers, such as riverbank pools formed by bank irregularities
and in the pools below riffles, where drifting invertebrate material
provides a ready food supply. During the first year at sea, the young fish
stay near shore. During the second and subsequent years, chinook salmon are
far-ranging, undertake extensive migration, and are found over a wide range
of depths, from surface waters to depths exceeding 100 m. It is not unusual
to encounter them at depths ranging from 20 to 110 m *232*.
Factors Limiting Availability of Food: Sedimentation is one of the major
factors that affects freshwater food availability. Excessive sedimentation
may inhibit production of aquatic plants and invertebrate fauna. Primary
food production is lowered above levels of 25 JTU (Jackson Turbidity Unit)
and visual references lost above levels of 30 JTU *232*.
Feeding Behavior: Chinook salmon are opportunistic feeders. Food
consumption is related directly to the types and abundance of items
available, although juvenile chinook salmon in fresh water do not seem to
utilize fish as food. Upon returning to fresh water, adult salmon no longer
feed but live off the fat stored up in the ocean *232*.
COMMENTS ON ADULT FOOD -
Chinook salmon primarily eat fish, except during the spring when
invertebrates (especially euphausids) are extremely abundant. In late
winter and early spring off San Francisco, chinook feed on herring,
rockfish, other fish, crab megalops, and squid. Euphausids and squid, and
later, herring, crab megalops, and rockfish comprise the spring diet. In
late spring through summer, rockfish dominate the diet, distantly followed
by other fishes and some invertebrates. Anchovies are the dominant diet
item for the remainder of the year. Chinook salmon frequent the waters of
southeast Alaska throughout the year and feed heavily on herring, smelt, and
eulachon. During the winter they move deeper and feed on halibut, rockfish,
Food Habits - 2 (DRAFT) - Food Habits
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
cod, and octopi *89*.
Adults eat fish, squid, euphasiids, shrimps, and crab larvae. Fishes make
up the bulk (97%) of the food of marine adults, with herring and sand lance
being the most frequently eaten. Crustaceans (composed dominantly of
euphasiids but including young crabs, crab megalops, and other miscellaneous
forms) are eaten in considerable numbers in the spring months (May and
June). The diet of adult chinook salmon at sea is related to the types and
abundance of food items available *232*.
COMMENTS ON JUVENILE FOOD -
Juvenile chinook are characterized as opportunistic drift and benthic
feeders, primarily eating insects in the stream-rearing phase of life. As
the young chinook salmon grow and move farther in to the marine environment,
their diet includes crab zoea, Pacific sand lance, eulachon, copepods,
euphausids, cephalopods, isopods, and amphipods.
Upon entering the estuary, chinook utilize a wide range of invertebrate prey
while retaining their insectivorous feeding habits. Gammarid amphipods,
insects, mysids, isopods, copepods, and fish larvae comprise the bulk of the
estuarine chinook juvenile diet *89*.
Following emergence from the redd and while still in fresh water, juveniles
feed on plankton, aquatic insect larvae, terrestrial insects, salmon eggs,
and spiders. They are characterized as opportunistic drift and benthic
feeders. Juvenile chinook salmon food habitat studies during August and
September in sloughs and clearwater tributaries of the middle reach of the
Susitna RIver suggest that the range and diversity of invertebrates in their
diet indicate an ability to adopt to variable conditions. Specimens
collected during the study had consumed both terrestrial and aquatic
invertebrates. Midges (Diptera: Chironomidae) were the numerically
dominant taxa and were consumed as larvae, pupae, and adults. Chironomid
adults and terrestrial invertebrates caught on the water surface, as opposed
to immature insects drifting in the water column, were often an important
food item for juvenile chinook salmon. Upon migration to the sea, young
chinook salmon eat crab larvae, amphipods, copepods, euphasiids,
cladocerans, barnacles, and a variety of small fish, such as sand lance,
eulachon, herring, rockfish, and smooth tongue *232*.
Types of Feeding Areas Used: Juveniles feed in low-velocity areas of
streams and rivers, such as riverbank pools formed by bank irregularities
and in the pools below riffles, where drifting invertebrate material
provides a ready food supply. During the first year at sea, the young fish
stay near shore *232*.
COMMENTS ON LARVAE FOOD -
Alevins absorb a yolk sac before emerging as free-swimming fry *89*.
Upon hatching, young alevin remain in the gravel for two to three weeks
until the yolk sac has been absorbed *232*.
Food Habits - 3 (DRAFT) - Environment Associations
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Temperature: Below 15 degrees C
E Water Temperature: Below 15 degrees C
A Water Temperature: Specified in Comments
G Dissolved Oxygen: Moderate [5-7 mg/l] oxygen concentrations
G Turbidity: Clear water
G Relation to Substrate: Unattached - normally free living
J Substrate: Rocks
A Substrate: Mud or silt
A Substrate: Rocks
G Bottom Type [Aquatic]: Mud or silt
A Bottom Type [Aquatic]: Sand
A Bottom Type [Aquatic]: Gravel
J Bottom Type [Aquatic]: Boulders
G Water Velocity [Instream Flow Group Increments]: Specified in Comments
G Water Depth Preference: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR RESTING ADULT ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR FEEDING JUVENILE ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR RESTING JUVENILE ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR FEEDING LARVAE ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR RESTING LARVAE ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR PUPAE ENVIRONMENTAL ASSOC_ - 89
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 89
Environment Associations - 1 (DRAFT) - Environment Associations
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Temperature: Adult spring chinook can survive in deep pools in the summer
with the surface temperature 23.0 deg C, but cannot spawn above 22.0 deg C.
Upper lethal temperature for chinook salmon is 25.1 deg C.
Salinity: Chinook salmon have been associated with salinities from 6.75 to
25.73 ppt in the Straits of Georgia off the Fraser River plume.
Dissolved oxygen: Chinook salmon can survive when resting with dissolved
oxygen levels as low as 2.0 mg/l and could swim against 0.8 ft/s current
for a day when dissolved oxygen concentrations were 3.0 mg/l.
Depth: The preferred depth for spawning is >0.24 m to 10 m for spring and
fall chinook and >0.30 m for summer chinook. Upstream migrations are
generally triggered by rains, which raise the river levels and change the
water temperature.
Water movement: A 70 mm chinook can maintain a home station facing
velocities of 0.23 m/s but lie under a layer of 0.45 m/s water and be
surrounded by velocities of 0.6 m/s.
Turbidity: Salmonid fishes will cease movement or migration in streams
with high silt loads (>4000 mg/l). Study has shown that exposure to low
levels of volcanic ash in a Y-test chamber caused chinook salmon to exhibit
significant avoidance reactions. Because turbid water absorbs more
radiation than clear water, a thermal barrier to movement and migration may
also develop.
Substrate: No substrate preference has been documented for adults in the
marine environment *89*.
COMMENTS ON RESTING ADULT ENVIRONMENTAL ASSOC_ -
Temperature: Adult spring chinook can survive in deep pools in the summer
with the surface temperature 23.0 deg C, but cannot spawn above 22.0 deg C.
Upper lethal temperature for chinook salmon is 25.1 deg C.
Salinity: Chinook salmon have been associated with salinities from 6.75 to
25.73 ppt in the Straits of Georgia off the Fraser River plume.
Dissolved oxygen: Chinook salmon can survive when resting with dissolved
oxygen levels as low as 2.0 mg/l and could swim against 0.8 ft/s current
for a day when dissolved oxygen concentrations were 3.0 mg/l.
Depth: The preferred depth for spawning is >0.24 m to 10 m for spring and
fall chinook and >0.30 m for summer chinook. Upstream migrations are
generally triggered by rains, which raise the river levels and change the
water temperature.
Water movement: A 70 mm chinook can maintain a home station facing
velocities of 0.23 m/s but lie under a layer of 0.45 m/s water and be
surrounded by velocities of 0.6 m/s.
Turbidity: Salmonid fishes will cease movement or migration in streams
with high silt loads (>4000 mg/l). Study has shown that exposure to low
levels of volcanic ash in a Y-test chamber caused chinook salmon to exhibit
significant avoidance reactions. Because turbid water absorbs more
radiation than clear water, a thermal barrier to movement and migration may
also develop.
Substrate: No substrate preference has been documented for adults in the
marine environment *89*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Temperature: The recommended temperatures for spawning range between 5.6
and 13.9 deg C. Adult spring chinook can survive in deep pools in the
Environment Associations - 2 (DRAFT) - Environment Associations
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
summer with the surface temperature 23.0 deg C, but cannot spawn above 22.0
deg C.
Dissolved oxygen: Although migrating adult chinook salmon encounter
dissolved oxygen levels of 3.0 to 4.0 ppm in the Duwamish River Estuary, it
could not be demonstrated that this impeded the spawning migration of
chinook salmon.
Substrate: Adult chinook salmon spawn in gravel ranging from 6 cm to 14 cm
in diameter. Gravel substrates from 1.3 cm to 10.2 cm in diameter have
been listed in the literature as acceptable for spawning.
Depth: Chinook salmon will spawn in rivers with depths of 0.10 m to 10 m.
The preferred depth for spawning is >0.24 m for spring and fall chinook
salmon and >0.30 m for summer chinook.
Water movement: Chinook salmon require enough current on spawning beds to
ventilate the eggs during incubation *89*.
COMMENTS ON RESTING JUVENILE ENVIRONMENTAL ASSOC_ -
Temperature: Optimum temperature for fingerlings is 17.0 deg C.
Salinity: Juvenile chinook salmon encounter a wide range in salinity when
moving from freshwater through an estuary and into the marine environment.
Estuaries normally maintain a freshwater lens above the area of saltwater
intrusion that smolts tend to occupy during the initial stages of their
estuary and marine residence.
Dissolved oxygen: A marked avoidance of oxygen concentrations at or below
4.5 mg/l by juvenile chinook in the summer at 20.0 deg C has occurred.
Decreased avoidance occurred in the fall as temperatures declined or as
dissolved oxygen concentrations rose above 4.5 mg/l, with no avoidance
noted at 6.0 mg/l.
Substrate: Spring chinook juveniles that overwinter in freshwater require
large boulder habitat for winter refuge areas. However, they prefer
different habitats than do steelhead. In the estuaries, juvenile chinook
salmon show a wide range of substrate associations including mud, sand,
gravel, and eelgrass.
Depth: Juvenile chinook salmon prefer deeper water (>0.5 m) than steelhead
in the same streams. Juvenile chinook occupy the water near the surface
during their initial marine stages and then utilize water down to 60 m.
Water movement: Juvenile chinook can detect and orient in water velocities
of 0.005 m/s.
Turbidity: Excessive amounts of sand and silt may limit production of
benthic invertebrates necessary for optimum rearing of juvenile fish.
Chinook salmon smolts may be quite tolerant of high concentrations of
volcanic ash and mudflow sediments. 96-hr LC50 values for these fish have
been determined to be 11,000 mg/l. Sublethal sediment concentrations did
not produce consistant effects on swimming performance or fatigue velocity.
Chinook smolts were much less tolerant of seawater after exposure to high
concentrations of volcanic ash and mudflow sediments, but low level
exposure did not affect them. Gill tissues revealed only minor effects
even at the highest exposure concentrations, but death at high
concentrations of these materials was caused by hypoxia. Behavioral
reactions to high suspended solid concentrations were identical to
responses to low dissolved oxygen: the fish stayed near the surface *89*.
COMMENTS ON RESTING LARVAE ENVIRONMENTAL ASSOC_ -
Temperature: Optimum temperature for chinook fry is 11.0 deg C.
Environment Associations - 3 (DRAFT) - Environment Associations
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
Turbidity: Fry emergence from the gravel may be hindered by excessive
amounts of sand and silt *89*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Temperature: Optimum temperature for chinook eggs is 11.0 deg C.
Dissolved oxygen: Chinook eggs require dissolved oxygen concentrations of
5.0 mg/l.
Water movement: Chinook salmon require enough current on the spawning beds
to ventilate the eggs during incubation *89*.
Environment Associations - 4 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY: Dorsal fin (10-14 rays), adipose stout and fleshy, anal
(13-19), pelvic (10), abdominal with a free-tipped fleshy appendage above
its insertion. Cycloid scales. Gill rakers (18-30) rough and widely spaced
on first gill arch. Body elongate, moderate, lateral compression.
IDENTIFICATION AIDS: Tail moderately forked with stiff outer rays.
Moderately large irregular black spots on back, upper sides, dorsal,
adipose, and both lobes of the caudal fin. Black lower gum line.
Juveniles: Parr marks appear as long vertical dark bars extending equally
above and below the lateral line. Parr marks are wider than or equal to the
width of spaces between marks.
SPAWNING: Chinook salmon exhibit at least three distinct life history
patterns. Spring chinook salmon populations occur in large river systems
where enough flow is available over the summer to hold these fish.
Spring-run fish may enter freshwater as early as February or March, but they
usually spawn between August and November. These fish travel upstream
slowly and remain for protracted periods in pools near the spawning grounds
and typically spawn in the upper reaches of rivers. Summer chinook salmon
enter the rivers from late spring through midsummer and hold in the river
until they spawn in the fall. Fall-run chinook salmon enter both large
rivers and small coastal streams in autumn. They generally move rapidly
during high water periods to the spawning areas and commence spawning
activities. Complete spawning normally occurs within 7 days after the
initial breeding activity. Males are attracted by females digging and
testing the gravel. When the female is satisfied with her excavation site,
spawning proceeds. The female deposits a portion of her ova in the gravel
depression while one primary male and possibly several subdominant males
move alongside simultaneously to fertilize the eggs. Following each of
these spawning acts, the female moves directly upstream to dig a new
depression, which also covers the eggs fertilized in the preceeding act.
The average depth of productive redds was reported to be 203 mm to 356 mm
beneath the surface of the stream bed. Columbia River chinook constructed
redds from 1.2 m to 10.7 m in diameter. Nest building commences earliest in
the uppermost reaches of the river and progresses sequentially downstream as
river temperatures drop to the levels encountered by the upstream spawners.
When females have expended their ova, the males desert them and apparently
search for additional matings until they are spawned out or die. Chinook
salmon live 2 to 4 weeks after spawning. During this time, females will
defend their redds and an area as wide as 6.1 m beyond the margin of the
redd against other females, but they will normally ignore male chinook
salmon.
FECUNDITY, EGGS, AND ALEVINS: Female chinook salmon produce 3,000 to 6,000
eggs. Fecundity is size related, and higher in southern populations.
Chinook salmon eggs are the largest of the Salmonidae. The eggs require an
average of 882 to 991 temperature units for hatching (1 temperature unit = 1
degree Fahrenheit above freezing for a period of 24 hours), with fewer
temperature units required for eggs incubated at lower temperatures. During
the incubation period, substantial mortality may be incurred by redd
disturbances from overspawning, fluctuating flows, dewatering, freezing,
Life History - 1 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
isolation, suffocation, and microbial infestation. Depending upon the
temperature regime of the natal stream, eggs hatch in the late fall or early
winter. The alevins remain in the gravel for 4 to 6 weeks until the yolk
sac is absorbed. The alevins are initially negatively phototactic and
migrate downward into the gravel. High CO2 levels may elicit a dispersal
response within the gravel. When the yolk sac is nearly absorbed, the
alevins begin to express positive rheotaxis. After yolk absorption, young
chinook salmon generally emerge after dark as free-swimming fry.
FRY AND SMOLTS: Fry spend 1 to 18 months in freshwater. Some fry migrate
seaward immediately after emergence while others live in the stream for
about a year before migrating downstream. Ninety percent of the juvenile
chinook from the Sacramento River migrate downstream from the middle of
January to the middle of March, and most enter saltwater by June of their
first year (6 to 10 months following spawning) at an average length of 41
mm. Downstream fall migrants, including both fall- and spring-run
juveniles, reach saltwater at an average length of 100 mm. In British
Columbia, 78% of the chinook salmon migrate to sea as fry while the
remaining 22% enter saltwater as yearlings. Some chinook populations,
particularly from coastal streams, leisurely feed and migrate downstream
rather than living in distinct reaches of the river for extended periods of
time. Spring chinook salmon from the upper reaches of large rivers, such as
the Columbia, exhibit the more familiar year-long freshwater rearing stage.
In warmer months, young chinook are associated with velocities and depths in
proportion to body size, shifting to faster, deeper waters as they grow.
Chinook are primarily drift and benthic feeders. During the day the fish
remain in a small home area. At night they settle to the bottom, usually
after moving inshore. In early autumn, juvenile chinook salmon emigrate
downstream from the tributaries to overwinter in larger streams, often
living in the substrate. Winter cover, especially large rocks, is important
in holding overwintering fish. Juvenile chinook salmon prefer deeper water
with smaller substrate particles than do steelhead.
Chinook salmon migrations into estuaries are correlated with periods of high
discharge and turbidity, and migration is normally heaviest at night. These
migrations occur primarily during spring and early summer, but continue at
lower levels through fall. Fish entering the estuary range from 35 mm to
160 mm according to several authors. The larger juveniles tend to migrate
earlier and growth increases in brackish estuarine waters. Spacial
distribution of juvenile chinook within an estuary may be size dependent,
while schooling in an estuary may be influenced by fright elicited in the
fish due to tidal cycles and wave action.
Estuarine residence times may be influenced by the occurrence of fall
freshets, population abundance, and various estuarine characteristics;
duration and timing of estuarine residence vary geographically with seasonal
differences. Chinook salmon in the Skagit River Estuary occupied the inner
estuarine salt marshes for 2 to 3 days before emigrating farther out in the
estuary. The larger smolts, greater than 46 mm, spent approximately a day
less in the salt marsh than did the smaller fish. Smolts congregated in
tidal streams at low tide, with the majority of fish observed in deep, slow
water over soft substrates. The highest chinook salmon densities occurred
in tidal streams without any freshwater influence.
It has been suggested that the abundance of the epibenthic prey fauna in
soft, packed substrate habitat attract juvenile chinook. In the Nanaimo
Life History - 2 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
River Estuary, chinook salmon were found in water a few centimeters to over
a meter deep over gravel, sand, and mud substrates. Where an extensive
estuarine environment exists, juvenile chinook will reside there for up to 2
months. Within estuaries and bays, juvenile chinook salmon utilize
shoreline areas extensively. Smaller fish may utilize the inshore areas
while larger ones occupy deeper waters. Juvenile chinook salmon in Similk
Bay primarily occupy the surface waters (93.8%) while a few (1.8%) extend
down to 18.3 m. In river systems with high flushing rates relative to the
amount of existing estuarine habitat, juveniles may move quickly through the
mouth of the river and into the receiving marine waters. From work on the
Snohomish River, it was hypothesized that fish carried in midstream have
little chance to contact the shoreline and are carried offshore by strong
river and tidal currents during ebb tide. Juvenile chinook salmon have been
observed in several nearshore habitats, inshore from the 20-m depth level,
between mid-May and September in Puget Sound.
During estuarine rearing, chinook salmon exhibit significant growth. A
minimum growth estimate of 2.6 mm per week for juveniles in the Duwamish
River Estuary has been calculated. Minimum growth estimates of 1.5% of fork
length per day have been indicated for juvenile chinook in the Skagit River
Estuary. This spurt of growth before entering the marine environment may be
vital to the subsequent early marine survival of juvenile chinook salmon.
MARINE STAGES: Upon leaving the rivers of Oregon, Washington, and British
Columbia, juvenile chinook salmon move up the coast in a northwesterly
direction. This migration is a relatively slow feeding and dispersal
movement with distance from the natal stream increasing with age.
Sacramento River chinook are caught off the Washington and Oregon coast
while Columbia River chinook are collected as far north as Alaska and as far
south as San Francisco, California. Columbia River fish dominate the catch
along the west coast of the Queen Charlotte Islands, and the Fraser
River fish replace the Columbia River stocks north of the Queen Charlotte
Islands. They remain in the marine environment between 1 and 6 years with
the average being 3 or 4 years. Certain races of chinook salmon, such as
the Puget Sound blackmouth, tend to remain in local marine areas. Two- to
5-year-old chinook salmon comprised the bulk of the troll catch in the
nearshore areas, while the offshore catches were dominated by 5- and
6-year-old fish. Chinook salmon captured in the outer waters of British
Columbia were on long spawning migrations, traveling southeast along the
Continental Shelf. The return migration was fairly rapid in comparison to
the feeding or dispersal migration.
One- and 2-year-old chinook salmon in the Straits of Georgia were caught
from the surface down to 30 m with the majority occupying the deeper water.
In southeast Alaska, chinook salmon reside in marine waters throughout the
year, feeding at relatively shallow depths in the spring and summer and
occupying deeper waters (60-80 m) in the winter.
Salmon spawning migrations are elicited by environmental cues, such as
temperature or salinity, olfaction, celestial navigation, and magnetic
orientation. The timing of this migration is innate, while the location or
destination of the migration is learned through imprinting.
GROWTH CHARACTERISTICS: Chinook fry emerge from the gravel during the
winter, and some will migrate to sea after the first month when about 30 mm
long. Some spring chinook populations enter saltwater as yearlings at
Life History - 3 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
lengths exceeding 100 mm *89*.
Breeding Habitat: The general nature of the spawning ground, which may be
located from just above tidal limits to great distances upstream (over 3,200
km in the Yukon River), varies considerably. Main channels and tributaries
of larger rivers serve as the major chinook spawning areas. Normally, the
spawning grounds are characterized by stream underflow (downwelling currents
or intragravel flow) created by the depth and velocity of the water, rather
than being associated with the emergence of groundwater. Ninety-five
percent of the redds in the Kamchatka River, USSR, were situated precisely
at the transition between a pool and a riffle. Many chinook salmon redds
were located near the upstream tips of vegetated islands in the Kenai River
where loose, clean gravels aggraded and where predominant substrates ranged
from 1.6 to 6.4 cm diameter materials. Areas just below log jams, where flow
through the gravel is increased as a consequence of reduced surface flow,
are also favorite spawning sites. Exceptions to what may be considered
normal breeding habitat and behavior have been documented. During late
October and early Noverber 1965, approximately 50 chinook salmon from
University of Washington hatchery stocks spawned in groundwater seepage
areas of gravel and sand beaches in Lake Washington. This behavior is
believed to have resulted from crowding and high water temperatures, both
unfavorable conditions, at the hatchery homing pond *232*.
Breeding Seasonality: In Alaska, mature chinook salmon ascend the rivers
from May through July. Generally, fish that appear at the river mouth
earliest migrate farthest. Peak spawning occurs from July through September
*232*.
Breeding Behavior: As with other salmon, adult chinook salmon return from
the sea and normally move into their natal freshwater streams to spawn. The
female selects the spawning site and digs the redd (nest) by turning on her
side and thrashing her tail up and down. The current washes loosened
substrate material downstream, and a depression 35 to 60 cm deep is formed
in the river bottom. Eggs and sperm (milt) are released simultaneously and
deposited in the redd. After egg deposition, the female moves to the
upstream margin of the redd and repeats the digging process. Dislodged
substrate is washed over the eggs. In this manner, the eggs are covered and
prevented from washing away. The process is repeated many times, and the
redd appears to move upstream. As a result of the continued digging, the
redd may grow to become 1.3 to 5.6 m in length and 1.5 to 3.3 m wide. A
female may dig several redds and spawn with more than one male. Males may
also spawn with several females *232*.
Age at Sexual Maturity: The age at which chinook salmon reach sexual
maturity ranges from two to eight years (generally zero to two years in
fresh water and one to seven years at sea), although the vast majority of
the fish mature in their third to sixth year. Age at maturity, like
freshwater age and ocean age, tends to be greater in the north than in the
south because more northern populations spend a longer time at sea. From
California northward to Cook Inlet, Alaska, for example, three, four, and
five-year-old fish prevail (there are significant numbers of six-year-olds
in some areas, but few if any seven- or eight-year-olds). Five- and
six-year-olds dominate runs from Bristol Bay northward, but seven- and
Life History - 4 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
eight-year-olds are not uncommon *232*.
Fecundity: Chinook salmon fecundity varies by stock and the size of the
female; however, northern stocks generally produce more eggs. In Alaska,
the number of eggs ranges from 4,242 to 17,255 per female *232*.
Frequency of Breeding: As with all Pacific salmon, the spawning cycle is
terminal. Both male and female die after spawning *232*.
Incubation Period/Emergence: The amount of time required for eggs to hatch
is dependent upon many interrelated factors, including 1) dissolved oxygen,
2) water temperature, 3) apparent velocity in gravel, 4) biological oxygen
demand, 5) substrate size (limited by percentage of small fine material), 6)
channel gradient and 7) configuration, 8) water depth, 9) surface water
discharge and velocity, 10) permeability, 11) porosity, and 12) light.
Generally speaking, factors 4 through 12 influence/regulate the key factors
1, 2, and 3. Eggs require about 900 temperature units (TU) to hatch and
become alevins and an additional 200 to 800 TUs to absorb their yolk sac.
The TUs for one day = mean 24-hour water temperature in degrees Farenheit -
32 oF + 1 oF if the mean temperature is 32 oF. Incubation of the eggs takes
place with both ascending and descending water temperatures. Depending on
the time of spawning and the water temperature, the eggs usually hatch in
late winter or early spring. The newly hatched fish, or alevins, remain in
the gravel until the attached yolk sac has been absorbed, normally two to
three weeks after hatching. The juveniles then work their way up through
the gravel to become free-swimming, feeding fry *232*.
Size of Use Areas: A conservative figure for the number of pairs of salmon
that satisfactorily utilize a given area of spawning gravel may be obtained
by dividing the area by four times the average size of the redds. The redd
area can be computed by measuring the total length of the redd (upper edge
of pit to lower edge of tailspill) and the average of several equidistant
widths. Chinook salmon redds in a Kenai River tributary stream are about
4.37 m2 in size. Mean values for mainstream Kenai River chinook salmon redds
are 6.38 m2. Because of the effects of dewatering and freezing, the amount
of available habitat at the time when adult salmon are spawning is a poor
indicator of the amount of actual habitat that is available as potential
incubation habitat. Estimates of available incubation habitat must take
into account the differential effects of dewatering and freezing in various
habitat types *232*.
Timing of Movements and Use of Areas: Young-of-the-year juveniles move
downstream in the fall to overwinter in areas of the stream with larger
substrate (possibly because it provides better cover). Out-migrating smolt
bound for the sea depart fresh water in the springtime. Smolt
out-migrations tend to be nocturnal. Adults return to fresh water during
the period of May through July. Studies on the Kenai River indicated that
of all radio-tagged adults returning to the spawning grounds, most moved
between 1400 and 2200 hours. Adult chinook salmon moved upstream mainly in
the daytime *232*.
Migration Routes: Large rivers serve as corridors for smolt out-migration.
Barriers to adult upstream movement include excess turbidity, high
Life History - 5 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
temperatures (20.0 oC or more), sustained high-water velocities, and
blockage of streams (log jams, waterfalls). While in the marine
environment, first-year ocean fish are confined primarily to coastal areas
and are much less abundant in the open ocean. During the second and
subsequent years of ocean life, they are found widely distributed in the
North Pacific Ocean and Bering Sea. Chinook salmon from Alaskan streams
enter the Gulf of Alaska gyre and move extensively across the northern
Pacific and in the Bering Sea, and during the summer their numbers increase
in the area of the Aleutian Islands and in the western Gulf of Alaska. Many
of the inshore fish of Southeast Alaska, however, appear to be of local
origin. Except for areas immediately adjacent to the coast it is possible
that chinook salmon do not occur in the high seas south of 40 oN. The
central Bering Sea is a feeding ground and migration path for immature
chinook salmon in Western Alaska (defined as the area from and including
Bristol Bay northward to Point Hope). Tag recoveries are known to occur in
the Bering Sea as far west at 172 deg 12' E (at 59 deg 03'N), whereas
scale-pattern and maturity studies, combined with seasonal distribution and
Japanese mothership and research vessels information, push the range further
west, to probably at least 160 deg to 165 deg E. These same stocks have
been found as matures in the North Pacific Ocean just south of Adak at 176
deg 18' W (at 51 deg 36' N). Scale-pattern analysis shows tentatively that
they may extend from 160-170 deg E to at least 175 deg W; but their
distribution to the south over this range, at least beyond 50 deg N, is even
more uncertain. Other North American chinook salmon (including stocks from
central Alaska [Cook Inlet] southward) are known to occur as immatures in
the North Pacific Ocean as far west as 176 deg 34' W (at 51 deg 29' W).
Recent coded-wire tag recoveries of chinook salmon marked in Oregon,
Southeast Alaska (Stikine River and Little Port Walter), and Southcentral
Alaska (Crooked Creek, a tributary of the Kasilof River on the Kenai
Peninsula) indicate that these stocks occur in the southeastern Bering Sea
north of the Alaska Peninsula. Tag recoveries occurred during the months of
November, February, April, and May in an area from 54 deg 21' to 55 deg 26'
N and 165 deg 21' to 167 deg 58' W. The tag recovery of the Crooked Creek
fish at 55 deg 26' N, 167 deg 58' W was a definite range extension of
Southcentral Alaska chinook salmon stocks into the Bering Sea *232*.
Natural Factors Influencing Populations: Juvenile chinook salmon are preyed
on by other fish (e.g., rainbow, cutthroat, Dolly Varden, coho salmon
smolts, and sculpins) and birds (e.g., mergansers, king fishers, terns,
osprey, other diving birds). Estuarine and marine predators include
fish-eating birds, pelagic fishes, killer whales, seals, sea lions, and
possibly the Pacific lamprey. The greatest natural mortality occurs in
fresh water during the early life stages and is greatly influenced by the
environment; therefore, deleterious changes in freshwater quality, quantity,
or substrate are most detrimental. Flooding can either wash away or bury
eggs. Natural sedimentation can smother eggs *232*.
Human-related Factors Influencing Populations: A summary of possible
impacts from human-related activities includes: alteration of preferred
water temperatures, pH, dissolved oxygen, and chemical composition;
alteration of preferred water velocity and depth; alteration of preferred
stream morphology; increase in suspended organic or mineral material;
increase in sedimentation and reduction in permeability of substrate;
Life History - 6 (DRAFT) - Life History
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
reduction in food supply; reduction in protective cover (e.g., overhanging
stream banks, vegetation, or large rocks); obstruction of migration routes;
shock waves in aquatic environment; and human harvest *232*.
LIFE HISTORY CODES -
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Mating System (Single breeding season): Promiscuity (
Nest Materials: Mud
Nest Materials: Sand
Average Number of Offspring/Reproductive Effort: 1,00
Average Number of Offspring/Reproductive Effort: Grea
Periodicity: Active at night
Periodicity: Active in day
COMMENTS ON LIFE HISTORY -
The juveniles apparently subordinate minimal space requirements to exploit
periods of short-term food abundance. Juvenile chinook salmon prefer deeper
water with smaller substrate particles than do steelhead. Interaction for
space between species is minimized by differing spawning and emergence
times *89*.
REFERENCES FOR LIFE HISTORY- 89 and 232
Life History - 7 (DRAFT) - Management Practices
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Regulating harvest of species being described
Existing Stocking captive-reared wild-strain animals
Existing Regulating commercial harvest gear types
Existing Regulating harvest - setting bag/creel limits
Beneficial Developing/maintaining suitable pH
Beneficial Controlling water levels
Beneficial Controlling sedimentation
Beneficial Establishing/maintaining nesting and escape cover
Beneficial Developing/maintaining stream bank vegetation
Beneficial Developing/maintaining stream structures
Adverse Migration barriers
Beneficial Regulating harvest of species being described
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 232
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 232
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 89
COMMENTS ON MANAGEMENT PRACTICES -
Nearshore and terminal area fisheries are conducted with purse seines and
gill nets, and inriver set net fisheries are allowed by treaty-Indian
fishermen in most river drainages.
Salmon fisheries management is an extremely complex problem due to
user-group allocations and mixed-stock and mixed-age fisheries. Optimum
yield is the desired management goal for this fishery. Ocean fisheries are
managed by a catch quota, while terminal area fisheries are managed by
subtracting escapement goals from pre-season run forecasts, which are
updated throughout the season. This yields the total allowable harvest,
which must be allocated among the user groups involved. Individual chinook
salmon stocks can be identified by studying the fine structure of the
scales. Stocks are artificially identified by extensive coded wire tagging
programs. Chinook salmon of Canadian and United States origin often are
intercepted on the high seas by Japanese motherships. These fish are
primarily taken as immature fish in the western Pacific Ocean and Bering
Sea. Estimated incidental catch of chinook salmon by foreign trawl vessels
was about 113,000 fish in 1981 *89*.
The greatest natural mortality occurs in fresh water during the early life
stages and is greatly influenced by the environment; therefore, deleterious
changes in freshwater quality, quantity, or substrate are most detrimental.
Flooding can either wash away or bury eggs. Natural sedimentation can
smother eggs *232*.
A summary of possible impacts from human-related activities includes:
alteration of preferred water temperatures, pH, dissolved oxygen, and
chemical composition; alteration of preferred water velocity and depth;
alteration of preferred stream morphology; increase in suspended organic or
Management Practices - 1 (DRAFT) - Management Practices
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
mineral material; increase in sedimentation and reduction in permeability of
substrate; reduction in food supply; reduction in protective cover (e.g.,
overhanging stream banks, vegetation, or large rocks); obstruction of
migration routes; shock waves in aquatic environment; and human harvest
*232*.
Management Practices - 2 (DRAFT) - References
Species salmon, chinook
Species Id M010030
Date 26 AUG 96
References
232 * State of Alaska Department of Fish, and Game. 1986. Alaska
Habitat Management Guide: Life Histories and Habitat
Requirements of Fish and Wildlife. (ed.). Alaska Department of
Fish and Game Juneau, Alaska:763.
89* Beauchamp, D. A., M.F. Shepard, G. B. Pauley. 1983. Species
Profiles: Life Histories and Environmental Requirements of
Coastal Fishes and Invertebrates (Pacific Northwest) -- Chinook
Salmon. U.S. Fish and Wildlife Service Biol. Rep. 82(11.6) pp 15.
References - 1