(DRAFT) - Taxonomy
Species salmon, chum
Species Id M010003
Date 26 AUG 96
TAXONOMY
NAME - salmon, chum
OTHER COMMON NAMES - dog salmon, fall salmon, calico salmon, chub and keta salmon
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 - keta,
SCIENTIFIC NAME - Oncorhynchus keta
AUTHORITY - Walbaum, 1792
TAXONOMY REFERENCES - 06, 255 and 232
COMMENTS ON TAXONOMY -
Caution must be used when extending information from one stock of chum
salmon to another stock. Environmental conditions from 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, chum
Species Id M010003
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Possibly in peril need more information
State special concern
Commercial/consumption
Migrant
Existing, FMP exists
REFERENCES FOR STATUS - 06 and 232
COMMENTS ON STATUS -
The chum salmon supports a valuable commercial fishery along the Pacific
coast from Washington to Alaska. This fish is the main income producer for
many villagers in southwestern Alaska. It occupies ecological niches in
both marine and estuarine waters and is important as both a predator and
prey species at various life stages.*06*
Although not a prime target for sport fishermen in the Pacific Northwest,
chum salmon are caught incidently by anglers fishing for coho and chinook
salmon.*06*
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 in 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, and 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 of the 17th coast Guard District, and a
representative from the U.S. Department of State. The council prepares
fishery management plans that 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 is a convention
comprised of Canada, Japan, and the United States established to provide for
scientific studies and for coordinating the collection, exchange, 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 be fished by Japanese nationals and fishing
vessels *232*.
Status - 1 (DRAFT) - Distribution
Species salmon, chum
Species Id M010003
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
REFERENCES FOR HABITAT - 06
COMMENTS ON HABITAT ASSOCIATIONS -
Anadromous species. Eggs and alevins (yolk-sac larvae) are benthic and
infaunal; fry and adults are benthopelagic; ocean dwelling juveniles are
epipelagic.
Habitat type: Eggs and alevins occur in rivers and streams, from intertidal
areas to 2,500 km upriver in large river systems, but they are normally
found in riverine areas less than 200 km from the sea. Fry are found in
rivers, estuaries, and marine waters, but prefer shallow waters (nearshore
and intertidal areas <1.0 meters) during their initial outmigration before
moving out to sea. Once at sea, juveniles are primarily epipelagic (0-60
meters), but may be found to depths of 95 m. Adults occur in neritic,
estuarine, and riverine waters.*255*
Substrate: Eggs and alevins are found primarily in medium-sized gravel
(about 2-4 cm in diameter) and are buried down to 40 cm. Recommended
spawning gravels range from 1.3-10.2 cm. Columbia redds were composed of
81 percent medium and small gravel (<15 cm diameter), 13 percent large
gravel (>15 cm), and 6 percent mud-silt-sand. Fry initially occur in
shallow areas of varying substrate.*255*
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Cutthroat trout
Rainbow trout
Dolly Varden
Coho salmon
Sculpin
Kingfisher
Merganser
Stonefly
Arctic grayling
Mallard duck
Lamprey
Bear
Eagle
Osprey
REFERENCES FOR SPECIES ASSOCIATIONS - 255 and 232
COMMENTS ON SPECIES ASSOCIATIONS -
Predation: In freshwater and estuarine environments the primary predators
are probably other salmonids. Chum fry are reportedly eaten by juvenile
coho, sockeye, and chinook salmon; cutthroat and rainbow trout; Dolly
Varden; sculpins; Pacific cod; and birds and ducks (kingfishers, mergansers,
and others). Predation is variable, depending on such factors as predator
and prey size, the amount of yolk on the fry, abundance of fry, and
composition of other prey. At sea, they are preyed on by lamprey, sharks,
and probably other large predatory fishes. Adult chum salmon are eaten by
marine mammals (killer whales, harbor seals, etc.), land mammals (bears),
and large predatory birds (osprey and eagles).*255*
Young chum salmon on the spawning grounds and during downstream migration
are preyed upon by cutthroat and rainbow trout, Dolly Varden, coho salmon
smolts, sculpins, kingfisher, merganser, other predaceous birds, and
mammals. Even stonefly larvae and possibly other predaceous insects may prey
on eggs and alevins. There is often heavy predation on eggs of spawning fall
chum salmon by arctic grayling and mallard ducks in such Yukon River
Habitat Associations - 1 drainage systems as the Delta, Sheenjek, and Toklat rivers. At sea, chum
salmon are preyed upon by marine mammals, lampreys, and, in the early sea
life, possibly by large fishes. Upon returning to fresh water to spawn,
adults fall prey to bears, eagles, osprey, and other mammals *232*.
Habitat Associations - 2 (DRAFT) - Food Habits
Species salmon, chum
Species Id M010003
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 06 and 232
LIFESTAGE FOOD FOOD PART
Juvenile Crustaceans Not Specified
Juvenile Copepods Not Specified
Juvenile See Comments; Food
Adult Crustaceans Not Specified
Adult Copepods Not Specified
Adult Osteichthyes Not Specified
Juvenile Detritus - Inorganic Not Specified
Juvenile Detritus Not Specified
Juvenile Diptera Larva stage
General Diptera Larva stage
Juvenile Diptera Pupa stage
General Diptera Pupa stage
Juvenile Plecoptra Juvenile stage
General Plecoptra Juvenile stage
Juvenile Ephemeroptera Juvenile stage
Juvenile Arachnids Not Specified
General Branchiopods Not Specified
General Copepods Not Specified
General Roundworms Not Specified
General Insects Not Specified
Juvenile Insects Larva stage
Juvenile Insects Pupa stage
Juvenile Insects Adult stage
Juvenile Zooplankton Not Specified
Juvenile Zooplankton Not Specified
Juvenile Diptera Not Specified
Juvenile Plecoptra Not Specified
Juvenile Ephemeroptera Not Specified
Juvenile Homoptera Not Specified
Juvenile Hymenoptera Not Specified
Juvenile Branchiopods Not Specified
Juvenile Copepods Not Specified
Juvenile Roundworms Not Specified
Juvenile Ostracods Not Specified
Juvenile Cirripeds Not Specified
Juvenile Malacostraca Not Specified
Juvenile Diptera Not Specified
Juvenile Arrow worms Not Specified
Juvenile Osteichthyes Larva stage
General Copepods Not Specified
General Crustaceans Not Specified
General Osteichthyes Not Specified
General Squid, Octopus Not Specified
General Molluscs Not Specified
Juvenile See Comments; Food See Comments
Food Habits - 1 (DRAFT) - Food Habits
Species salmon, chum
Species Id M010003
Date 26 AUG 96
LIFESTAGE FOOD FOOD PART
General See Comments; Food See Comments
REFERENCES FOR GENERAL FOOD - 06 and 232
REFERENCES FOR ADULT FOOD - 06
REFERENCES FOR JUVENILE FOOD - 06 and 232
COMMENTS ON FOOD -
During their estuarine existences chum salmon are size-selective predators
that preferentially feed on epibenthic organisms: harpacticoid copepods,
gammaridean amphipods, cumaceans, and mysids. After reaching a length
greater than 55 mm, juvenile chum salmon migrate to the offshore neritic
zone and feed on larger planktonic organisms such as calonoid copepods,
hyperiid amphipods, larvaceans and fish larvae .*06*
Food limitation in shallow waters may induce movement to deeper waters where
their diet shifts to include more pelagic prey, such as calanoid copepods,
hyperiid amphipods, crustacean larvae, and larvaceans. In the ocean, they
feed on euphausiids, hyperiid amphipods, squids, pteropods, crab larvae, and
fishes.*255*
Copepods, tunicates, and euphausiids dominate the diet at sea. Other items
eaten at sea include other fishes, pteropods, squid, and mollusks *232*.
Types of Feeding Area Used: Because chum salmon spend such a short time in
natal water following emergence from the gravel, no data are available on
freshwater feeding locations. At sea, the fish are found from close to the
surface down to at least 61 m. There is some indication of vertical
movement according to the time of day, with the fish tending to go toward
the surface at night and deeper during the day. This is probably a response
to movements of food organisms *232*.
Factors Limiting Availability of Food: Chum salmon juveniles that feed
while in fresh water eat benthic organisms. Excessive sedimentation may
inhibit production of aquatic plants and invertebrate fauna and thereby
decrease available food *232*.
Feeding Behavior: Juvenile daily food intake while in fresh water increases
as water temperatures increase. A study found that many more food items
were contained in the stomachs of juvenile chum salmon collected in daytime
than in those collected at night - an average of 124 items versus 4. It
also found that the fry fed selectively. Relatively more cladocerans,
decapod zoeae, and larvaceans were eaten than appeared in the samples of
available planktonic food items. Visual observations of individual chum
salmon fry in shore-oriented schools indicate that their feeding varied with
the speed of the water current. At velocities of 0 to 10.7 cm/s, a fry
would typically swim a darting course as much as three times its body length
to capture food item. At higher velocities, 10.8 to 19.8 cm/s, schools of
fry sometimes held position relative to the shore or bottom while facing the
current, and an individual would typically deviate up, down, or to the sides
no more than one-third of its body length to capture oncoming food. At
Food Habits - 2 (DRAFT) - Food Habits
Species salmon, chum
Species Id M010003
Date 26 AUG 96
still higher velocities, 19.9 to 24.4 cm/s, fry in schools often held a
constant position relative to shore or bottom but did not feed. Fry that
appeared to be in visual contact with the shore or bottom avoided currents
above 24.4 cm/s unless frightened. Adult feeding seems to be opportunistic
and is based on the availability of, rather than a preference for, certain
kinds of food. Upon returning to fresh water to spawn, adults cease feeding
and obtain energy from body fat and protein *232*.
COMMENTS ON JUVENILE FOOD -
Alevins live primarily off their yolk-sac. Fry may not feed in fresh water
if their migration to estuarine waters is quick, however, if freshwater
residency is lengthy, fry will feed on aquatic and terrestrial insects and
small crustaceans. Chironomid larvae appear to be particularly important.
Feeding in nearshore marine areas and estuaries by fry and fingerlings
appears to be an important component of chum salmon life history. Initially
chums feed in shallow waters and concentrate on epibenthic prey, such as
harpacticoid copepods and gammarid amphipods, but they may also eat
terrestrial insects and other small crustacea. Young chums are
size-selective feeders.*255*
Sixty-three percent of the preemergent juveniles excavated from redds in the
Traitors River of Southeast Alaska contained items such as sand or detritus
in the digestive tract. Of the total sample, only 13% contained food
organisms that included chironomid larvae and pupae, plecopteran nymphs,
ephemeropteran nymphs, and an arachnid. Most chum salmon juveniles begin
their downstream migration to the sea soon after emergence. Young chum
salmon with only a short distance to travel probably do not feed until they
reach the ocean. A study sampled 40 downstream-migrating chum salmon in
the short, coastal Traitors River and found that 22.5% contained substantial
numbers of chironomid pupae and plecopteran nymphs. Those that must spend
several days to weeks on their journey feed actively on chironomid larvae,
cladocerans (water fleas), copepods, nematodes, and a variety of mature and
immature insects. Stomach contents of chum salmon fry caught in the main
stem of the Noatak River, its tributaries, and its backwaters, during the
period May through early August reveal that the fry had fed mainly on the
larvae, pupae, and adult forms of insects. Only 4% of the stomach contents
were of other types of organisms, and, of these, most were zooplanktors.
The primary insect prey species were of the order Diptera and the order
Plecoptera. Other types of insects were represented and included specimens
from the orders Ephemeroptera (mayflies), Homoptera, and Hymenoptera.
Zooplanktors included speciments from the order Cladocera. Cyclopoid and
Harpacticoid forms of the subclass Copepoda were also represented. Some
chum salmon fry had also consumed roundworms. During their early sea life
they feed on a wide variety of organisms, such as diatoms, many small
crustaceans (e.g., ostracods, cirripeds, mysids, cumaceans, isopods,
amphipods, decapods), dipterous insects, chaetognaths, and fish larvae.
Chum salmon fry in Traitors Cove consumed food items that were mostly from
0.3 to 3.0 mm long. They also tended to feed on larger and harder items
than did pink salmon, as evidenced by the greater incidence of harpacticoid
copepods, collembolans (intertidal spring tails), cumaceans, and chironomids
in chum salmon. Benthic and intertidal forms of mysids, cumaceans, isopods,
amphipods, and insects were rare in plankton samples, and their presence in
some of the stomachs shows that chum salmon did on occasion feed in these
Food Habits - 3 (DRAFT) - Food Habits
Species salmon, chum
Species Id M010003
Date 26 AUG 96
ecological niches. The food of chum salmon fry caught in the brackish water
areas in Kotzebue Sound during June and early July consisted largely of
insects. Zooplankton, which made up most of the remainder, were mostly
copepods. Chum salmon fry caught near Cape Blossom in Kotzebue Sound in
more saline water than other samples were found to be feeding primarily on
cladocerans (Chydorinea) and copepods *232*
COMMENTS ON LARVAE FOOD -
Upon hatching, young alevin remain in the gravel for 30 to 50 days until
their yolk sacs are absorbed *232*.
Food Habits - 4 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
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
BA Water Temperature: Below 15 degrees C
FJ Water Temperature: Below 15 degrees C
A Water Temperature: Below 15 degrees C
A Dissolved Oxygen: Specified in Comments
E
J
E Water Temperature: Below 15 degrees C
E Water Temperature: Specified in Comments
L Water Temperature: Below 15 degrees C
L Water Temperature: Specified in Comments
J Water Temperature: Between 21-27 degrees C
J Water Temperature: Below 15 degrees C
LIM Water Temperature: Between 21-27 degrees C
LIM Water Temperature: Below 15 degrees C
J Turbidity: Specified in Comments
A Turbidity: Specified in Comments
E Flow: Specified in Comments
A Water Temperature: Between 15-21 degrees C
A Water Temperature: Below 15 degrees C
A Water Temperature: Specified in Comments
G Water pH: Between 6.5-8.5
G Water pH: Between 8.5-10.0
G Water pH: Specified in Comments
E Dissolved Oxygen: Specified in Comments
E Dissolved Oxygen: Low [less than 5 mg/l] oxygen concentrations
E Dissolved Oxygen: Moderate [5-7 mg/l] oxygen concentrations
E Water Temperature: Specified in Comments
BA Water Depth Preference: Less than 1 ft.
BA Water Depth Preference: 1-5 ft.
BA Water Depth Preference: 5-10 ft.
BA Water Depth Preference: Specified in Comments
E Substrate: Rocks
E Substrate: Specified in Comments
BA Substrate: Rocks
BA Substrate: Specified in Comments
BA Aquatic Features: Riffles
BA Aquatic Features: Specified in Comments
J Dissolved Oxygen: Low [less than 5 mg/l] oxygen concentrations
J Dissolved Oxygen: Specified in Comments
J Water Temperature: Below 15 degrees C
Environment Associations - 1 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
J Water Temperature: Specified in Comments
J Dissolved Oxygen: High [greater than 7 mg/l] oxygen concentrations
J Dissolved Oxygen: Specified in Comments
A Dissolved Oxygen: Specified in Comments
G Dissolved Oxygen: Moderate [5-7 mg/l] oxygen concentrations
G Dissolved Oxygen: High [greater than 7 mg/l] oxygen concentrations
G Dissolved Oxygen: Specified in Comments
E Turbidity: Specified in Comments
E Substrate: Specified in Comments
E Water Depth Preference: Specified in Comments
FA Water Depth Preference: Less than 1 ft.
FA Water Depth Preference: 1-5 ft.
FA Water Depth Preference: 5-10 ft.
FA Water Depth Preference: 10-25 ft.
FA Water Depth Preference: 25-50 ft.
FA Water Depth Preference: 50-100 ft.
FA Water Depth Preference: 100-200 ft.
FJ Water Temperature: Between 15-21 degrees C
FJ Water Temperature: Below 15 degrees C
FJ Water Temperature: Specified in Comments
E Water Temperature: Below 15 degrees C
E Water Temperature: Specified in Comments
L Water Temperature: Below 15 degrees C
L Water Temperature: Specified in Comments
J Water Temperature: Between 21-27 degrees C
J Water Temperature: Specified in Comments
LIM Water Temperature: Between 21-27 degrees C
LIM Water Temperature: Specified in Comments
J Water Temperature: Below 15 degrees C
LIM Water Temperature: Below 15 degrees C
A Water Temperature: Between 15-21 degrees C
A Water Temperature: Below 15 degrees C
A Water Temperature: Specified in Comments
G Water pH: Between 6.5-8.5
G Water pH: Between 8.5-10.0
G Water pH: Specified in Comments
E Dissolved Oxygen: Specified in Comments
E Dissolved Oxygen: Low [less than 5 mg/l] oxygen concentrations
E Dissolved Oxygen: Moderate [5-7 mg/l] oxygen concentrations
E Water Temperature: Specified in Comments
BA Water Depth Preference: Less than 1 ft.
BA Water Depth Preference: 1-5 ft.
BA Water Depth Preference: 5-10 ft.
BA Water Depth Preference: Specified in Comments
E Substrate: Rocks
E Substrate: Specified in Comments
BA Substrate: Rocks
BA Substrate: Specified in Comments
BA Aquatic Features: Riffles
BA Aquatic Features: Specified in Comments
J Turbidity: Specified in Comments
A Turbidity: Specified in Comments
Environment Associations - 2 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
E Flow: Specified in Comments
J Dissolved Oxygen: Low [less than 5 mg/l] oxygen concentrations
J Dissolved Oxygen: Specified in Comments
J Water Temperature: Below 15 degrees C
J Water Temperature: Specified in Comments
J Dissolved Oxygen: High [greater than 7 mg/l] oxygen concentrations
J Dissolved Oxygen: Specified in Comments
A Dissolved Oxygen: Specified in Comments
G Dissolved Oxygen: Moderate [5-7 mg/l] oxygen concentrations
G Dissolved Oxygen: Specified in Comments
G Dissolved Oxygen: High [greater than 7 mg/l] oxygen concentrations
E Turbidity: Specified in Comments
E Substrate: Specified in Comments
E Water Depth Preference: Specified in Comments
FA Water Depth Preference: Less than 1 ft.
FA Water Depth Preference: 1-5 ft.
FA Water Depth Preference: 5-10 ft.
FA Water Depth Preference: 10-25 ft.
FA Water Depth Preference: 25-50 ft.
FA Water Depth Preference: 50-100 ft.
FA Water Depth Preference: 100-200 ft.
FA Water Depth Preference: Specified in Comments
FJ Water Temperature: Between 15-21 degrees C
FJ Water Temperature: Below 15 degrees C
FJ Water Temperature: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 255 and 232
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 255 and 232
REFERENCES FOR JUVENILE ENVIRONMENTAL ASSOC_ - 255 and 232
REFERENCES FOR FEEDING JUVENILE ENVIRONMENTAL ASSOC_ - 255 and 232
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 255 and 232
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
There is no optimum pH value for fish in general; in water where good fish
fauna occur, however, the pH usually ranges between 6.7 and 8.3. The State
of Alaska water quality criteria for freshwater growth and propagation of
fish call for pH values of not less than 6.5 or greater then 9.0, with
variances of no more than 0.5 pH unit from natural conditions *232*.
Environment Associations - 3 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
State of Alaska water quality criteria for the growth and propagation of
fish state that DO shall be greater than 7 mg/l in waters used by
anadromous and resident fish. In no case shall DO be less than 5 mg/l to a
depth of 20 cm in the interstitial waters of gravel utilized by anadromous
or resident fish for spawning. In no case shall DO above 17 mg/l be
permitted. The concentration of total dissolved gas shall not exceed 110%
at any point of sample collection *232*.
COMMENTS ON LIMITING ENVIRONMENTAL ASSOC_ -
Upper lethal temperature is 25.6 C, lower lethal is 0.0 C.*255*
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Adults migrate upstream in temperatures of just above freezing to 21.1 C,
but optimum temperatures are 8.3-15.6 C. Adults migrate upstream in
velocities up to 2.44 m/sec and successfully spawn in velocities of 46-101
cm/sec. Dissolved oxygen (DO) levels below saturation can adversely affect
swimming performance of adults: DO values above 80 percent saturation, with
temporary levels no lower than 5.0 mg/l, are recommended for spawning.*255*
In Alaska, adult chum salmon have migrated upstream in temperatures ranging
from 4.4 to 19.4 oC, with peaks of migration occurring between 8.9 to 14.4
oC. A study suggests water temperature criteria for successful upstream
migration from 8.3 to 15.6 oC, with an optimum of 10 oC *232*.
Adult swimming performance can be reduced by levels of DO below air
saturation *232*.
High suspended sediment loads could be inhibiting to adults attempting an
upstream migration. Exposure can lead to tail rot and reduciton of gas
exchange across gills by physical damage, coating, or accumulation of
mucous *232*.
Chum salmon have less ability than other salmon to surmount obstacles and
in general show less tendency to migrate upstream beyond rapids and
waterfalls. The upstream passage criteria were primarily determined by
depth of water, were lightly affected by the length of the reach, and were
not significantly influenced by channel configuration or substrate size
*232*.
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
At sea, the fish are found from close to the surface down to at least 61
m. There is some indication of vertical movement according to the time of
day, with the fish tending to go toward the surface at night and deeper
during the day *232*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Recommended spawning temperatures range from 7.2-12.8 C, with incubation
temperatures 4.4-13.3 C.*255*
Spawning has occurred in Alaskan waters at temperatures from 6.9 to 12.8
oC, with preferred temperature ranges of 7.2 to 12.8 oC *232*.
Turbid water will absorb more solar radiation than clear water and may thus
Environment Associations - 4 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
indirectly raise thermal barriers to adult upstream spawning migration
During spawning, chum salmon in the Chena River of Alaska make redds in
water depths ranging from 5 to 120 cm. Those in the side channels and
sloughs of the middle reach of the Susitna River seembed to prefer depths
of 9.6 to 70.1 cm for spawning, although it was determined that depth
alone, if greater than 70.1 cm, would not likely affect chum salmon
spawning within the ranges of conditions encountered in the study sites.
Water velocity at spawning sites has ranged from 0 to 118.9 cm/sec.
Spawning chum salmon in sloughs and side channels of the middle reach of
the Susitna River exhibited a general preference for velocitites between 0
and 39.6 cm/sec. The ADF&G states that optimum stream velocity is 10 to 100
cm/sec (presumably for spawning and incubation) *232*.
Spawning chum salmon in sloughs and side channels of the middle reach of
the Susitna River seem to prefer substrates of larger gravel and rubble
ranging in size from 2.5 cm to 22.8 cm in diameter for spawning.
Generally, substrates with a percentage of fine particles (less than 0.833
mm in diameter) greater than 13% are of poor quality because of reduced
permeability. Chum salmon, however, often spawn in areas of upwelling
ground water and may therefore be able to tolerate higher percentages of
fines than would seem desirable if some of the fines are kept in suspension
by the upwelling water. Studies of slough and side channel habitat within
the middle reach of the Susitna River not that spawning chum salmon appear
to key on upwelling areas. The ADF&G observed that spawning usually occurs
in riffle areas and that chum salmon generally avoid areas where there is
poor circulation of water through the stream bed *232*.
COMMENTS ON JUVENILE ENVIRONMENTAL ASSOC_ -
Optimum outmigration temperatures for fry are 6.7-13.3 C. Ocean
dwelling juveniles occur in waters of 1.0-15.0 C, but prefer 2.0-11.0
C.*255*
Fry show a preference for salt water and cannot live for extended periods
in fresh water. A limited residence in mesohaline (10-15 ppt) estuarine
environment may be needed for complete adaptation to seawater.*255*
Downstream migration to the sea has occurred at temperatures between 3.0
and 5.5 oC for Delta River fall chum salmon. Peak movements occur at
warmer temperatures (i.e., 5.0 to 14 oC). The upper lethal temperature
limit of British Columbia chum salmon juveniles was found to be 23.8 oC.
The lower lethal temperature was found to be 0.1 oC *232*.
Studies concerning juvenile chum salmon dissolved oxygen requirements
indicate lower thresholds of 1.5 mg/l at water temperatures of 10 oC.
Dissolved oxygen levels of 8 to 9 mg/l at 8 to 10 oC seem most favorable
*232*.
Prolonged exposure to turbid water causes gill irritation in juveniles that
can result in fungal and pathogenic bacterial infection *232*.
Upon emergence from the gravel of short streams, chum salmon juveniles
migrate mainly at night and seek cover in the substrate during the daytime
if the journey is not completed in one night. Chum salmon fry, after
schooling has occurred during downstream migration, use the protection of
Environment Associations - 5 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
schools during daylight and no longer seek protection in the substrate
*232*.
COMMENTS ON FEEDING JUVENILE ENVIRONMENTAL ASSOC_ -
Juvenile daily food intake while in fresh water increases as water
temperatures increase. At 4 to 10 oC the weight of food eaten daily was 5
to 10% of the body weight; at 12 to 20 oC it was 10 to 19% of the body
weight. At velocities of 0 to 10.7 cm/s, a fry would typically swim a
darting course as much as three times its body length to capture a food
item. At higher velocities, 10.8 to 19.8 cm/s, schools of fry sometimes
held position relative to the shore or bottom while facing the current, and
an individual would typically deviate up, down, or to the sides no more
than one-third of its body length to capture oncoming food. At still
higher velocities, 19.9 to 24.4 cm/s, fry in schools often held a constant
position relative to shore or bottom but did not feed. Fry that appeared
to be in visual contact with the shore or bottom avoided currents above
24.4 cm/s unless frightened *232*.
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Emergence from the gravel has occurred at temperatures between 3.0 and 5.5
oC for Delta River fall chum salmon *232*.
A gravel substrate was found to prevent yolk sac malformations of alevins
reared at 12 oC and water velocities of 100 cm/hr. Alevins reared on a
smooth substrate with identical temperature and water velocities were
susceptible to yolk sac malformation. Since alevins prefer to maintain an
upright position, which is difficult on flat surface, the swimming activity
to right themselves results in continual rubbing on the flat surface, which
is thought to injure the yolk and cause malformation *232*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Eggs can survive lower temperatures provided initial development has
progressed to a stage that is cold-water tolerant. Optimum outmigration
temperatures for fry are 6.7-13.3 C.*255*
Eggs and alevins are primarily freshwater, but can tolerate euhaline
conditions for short periods.*255*
Egg hatching and alevin development have occurred in Alaska at temperatures
ranging from 0.2 to 6.7 oC during the winter months. Optimal incubation
temperatures, however, appear to range between 4.4 and 13.3 oC. During
chum salmon incubation studies in tributary, slough, main stem, and side
channel habitats of the middle reach of the Susitna River, Alaska, it found
that the pattern of accumulation of thermal units for developing salmon
embryos varies between spawning habitat types. Tributary habitats
typically have intragravel water temperatures that are strongly influenced
by surface water temperatures. This results in relatively high intragravel
water temperatures during the fall and spring months, with nearfreezing
water temperatures during the intervening winter months. Slough habitats
generally have relatively high and more stable intragravel water
temperatures during most of the incubation period because of the influence
of suitable upwelling sources. Main stem habitats are similar to tributary
habitats, having winter intragravel water temperature that are strongly
influenced by surface water temperatures. They differ, however, from
Environment Associations - 6 (DRAFT) - Environment Associations
Species salmon, chum
Species Id M010003
Date 26 AUG 96
tributary habitats by having colder water temperatures during fall and
spring periods. In general, winter intragravel water temperatures in side
channel habitats are quite variable and may reflect any of the patterns
exhibited by the other habitat types, depending upon the relative
influences of and relationships between upwelling and surface water sources
*232*.
The supply of dissolved oxygen to eggs and alevins is of critical
importance because a low (less than 1 ppm) supply leads to increased
mortality or delay in hatching and/or decreased fitness. Early stages
exhibit a plasticity in which development may decelerate virtually to zero
under extreme hypoxial conditions. In later stages, this plasticity is
lost, and oxygen levels that would produce no more than a cessation of
development at earlier stages become rapidly lethal. The rate of supply to
the embryos and alevins is influenced primarily by the D.O. concentration
of the source water and the rate of flow through the gravel substrate.
Dissolved oxygen levels as low as about 2 mg/l can meet the oxygen
requirements of eggs and alevins if the rate of flow of intragravel water
is sufficient. Intragravel D.O. concentrations in the Chena River during
incubation of chum salmon eggs ranged from 0.6 to 6.5 mg/l and resulted in
low survival rates at the lower concentrations and high survival rates at
the higher concentrations *232*.
Sedimentation causes high mortality to eggs and alevin by reducing water
interchange in the redd. If 15 to 20% of the intragravel spaces become
filled with sediment, salmonid eggs have sufferred significant (upwards to
85%) mortality *232*.
The flow of water in the stream channel is important to incubating embryos
in promoting an adequte intragravel flow and in protecting the substrate
from freezing temperatures. Heavy mortality of embryos can occur during
periods when there is a relatively high or a relatively small discharge.
Flooding can cause high mortality by eroding eggs from the redds or by
depositing fine sediments on the surface of the redds which can reduce
permeability or entrap emerging fry. Low discharge periods can lead to
dessication of eggs, low oxygen levels, high temperatures, or during cold
weather, freezing *232*.
Egg incubation and alevin development occur in substrates ranging widely in
size and composition. Chum salmon excavate redds in gravel beds with a
particle size of 2 to 4 cm diameter, but they will also construct redds in
substrates with particles of a greater size and will even use bedrock
covered with small boulders *232*.
Environment Associations - 7 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
LIFE HISTORY
Morphology/Identification:
Dorsal fin 10-13 rays; adipose fin small, slender, fleshy, caudal forked;
anal fin 13-17 rays; pectorals 16 rays; pelvic 10 rays and abdominal
position, each with a free-tipped fleshy appendage above its insertion.
The gillrakers are on the first arch 18-30 and the body is elongate and
moderately compressed.
Recognizable by the absence of large black spots on the body and fins,
and by the slender caudle peduncle; adult chum salmon are unique by
having white tips on their pelvic and anal fins, which distinguish them from
sockeye salmon. Maturing fish have a series of dark bars and red coloring
on sides, and some gray blotches. Juvenile parr marks appear as slender
bars, scarcely extending below lateral lines; have green irridescence on
back.
Spawning
Chum salmon are anadromous like other North American species of salmon, but
the time spent in freshwater is brief and primarily for reproduction . Chum
salmon migrate to the estuaries during their first spring or summer of life
and, like pink salmon, spend minimal time rearing in freshwater. In this
respect, they are considerably unlike sockeye, coho, and chinook salmon,
which spend longer times in freshwater. Adult chum salmon live in the
offshore marine or estuarine environments.
Like all species of Oncorhynchus, the chum salmon return to the stream in
which they were hatched, and then die after spawning. Chum salmon are the
last of the Pacific salmon to return to their natal streams , usually
leaving the marine waters in summer and late fall to begin their upstream
migration. However, in Puget Sound, adult chum salmon enter freshwater as
late as March. Chum salmon may enter freshwater to spawn as 3, 4, or 5
year-old fish. Groups of fish that enter the rivers early in Southern
British Columbia have a higher proportions of older fish (4 and 5-year-olds)
than those that enter the streams later. Most chum salmon spawn above the
saltwater zone but within 200 km of the sea, although some chum salmon have
been reported to migrate up to 322 km upstream to spawn.
Most rivers have only a summer and fall run of spawning chum salmon.
However, in the Puget Sound streams, there are three distinct chum salmon
runs: early - from mid-August through October; normal - from November
through December; and late - from January through March (J. Ames, 1984,
Washington State Department of Fisheries, Olympia; pers. comm.). Adult
chum salmon do not feed during the upstream migration and generally travel
about 20 km per day. It was reported that the time spent by
adults in freshwater (time of stream entry to death ) to be 11 to
18 days. However, the freshwater life of adult chum salmon that spawn in
large river systems is sometimes twice that long. In Southern
British Columbia, the average size of those that spawned in small
streams was smaller than the average of those that spawned in large
rivers.
The female chum salmon chooses a nest site on the basis of gravel
substrate. The female chum salmon excavates the redd in gravel
by turning to one side and rapidly flexing her body, creating water
Life History - 1 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
current and removing gravel with the caudal fin. After the depression
is complete, the female and dominant male enter the redd and simultaneously
extrude eggs and milt. Not all eggs are deposited at one time, as multiple
egg pockets are made. Tautz and Grott (1975) described the female chum
salmon as the dominant member of the spawning pair in the sense that the
activity of the male occurs in response to the quivering of the spawning
area by the female.
The area of chum salmon redds ranges from 0.3 to 4.5 m2 and averages about
2.3 meters squared. It has been suggested that a spawning pair requires a
total area of 9.2 meters squared. However, since chum salmon tend to
spawn in groups, this large additional amount of inter-redd spacing
(approximately 7.0 meters squared) is probably unnecessary and a realistic
optimum is closer to 2.0 m2 per female. Superimposition of redds
by later spawners may remove previously deposited eggs from the gravel.
Fecuncity, Eggs, and Alvins
Egg size: Eggs are reported to be 6.0-9.5 mm in diameter after
fertilization.
Female chum salmon produce from 900 to 8,000 eggs, with fecundity of
samples from North America and Asia averaging 2,000 to 3,000 eggs.
Factors that influence egg survival include superimposition of redds
by later spawners, sedimentation, low oxygen, preditors, light, freezing,
and erosion of stream beds by flooding and drought. Drought can
have two effects: (1) eggs or alvins may be killed through lack of
stream flow, which can result in insufficient dissolved oxygen, siltation,
or dessication; and (2) spawner may be forced to use inappropriate spawning
sites because of low flows.
Egg density did not influence fry survival but altered the time of
emergence, which in turn influenced fry condition, which is measured by the
length-to-weight relationship (Kapuscinki and Lannan 1983). The survival
rate from egg to fry is typically less than 10%. Chum salmon eggs
incubate in the gravel from 50 to 130 days. After hatching, the
larve with yolk sacs attached (alvins) remain in the gravel. The yolk
sacs are fully absorbed in 30 to 50 days later. Alvins emerge as fry in the
spring.
Fry and Smolts
Most chum salmon fry begin their downstream migration to the ocean soon
after emergence. In general, increased fry emergence results from increased
deposition of eggs, the more progeny produced up to a limit of about 333 fry
per m2 . Some fry remain in freshwater for several weeks --- especially
those that are hundreds of miles from the ocean. The out migration occurs
mostly at night in the spring (Hale 1981). Chum salmon 80-mm long occur in
the streams during the summer months, but they typically enter the ocean by
the end of the summer.
It is important that some rearing take place in the estuary because chum
fry reared exclusively in freshwater may be at a distinct disadvantage when
they enter saltwater.
The period of early marine residence, the estuarine- to -oceanic
transition (at <55 mm total length) is considered the most important stage
in the life history of the chum salmon, and the one which ultimately
Life History - 2 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
determines the number of adult returns. After the chum salmon reach a size
greater than 55 mm, they move into the offshore neritic zone. It appears
that the estuarine environment provides a refuge from predation and an
abundance of preferred epibenthic prey until juvenile fish reach a
length that is more advantageous for oceanic survival.
The fry enter the estuaries in schools, usually by June, and remain until
mid to late summer. The young chum salmon feed mainly in the estuaries,
though some go back into freshwater areas with the changing tides to feed.
By mid August to September, all juveniles at lengths of 150-225 mm
have left the river estuaries for the offshore ocean environments.
Prolonged rearing in freshwater and extended rearing close to the
point of saltwater entry may cause higher mortality of the juvenile chum
salmon than would otherwise be expected.
After leaving the estuarine environment, immature chum salmon become
widely distributed at sea throughout the North Pacific Ocean to a
southern limit of about 40 to 44 degrees N latitude.
Mature salmon range from age 2 to age 7, although age 6 and age 7 fish
are not commonly seen. Adults range from 0.8 to 13.4 kg in weight,
with the mean size for sexually mature fish being 60 to 75 cm and
4.0 to 7.0 kg. Maturing adults begin their migration to natal
streams in the last few months of their lives. Most upstream migrants
have spent 2 to 4 years at sea. It was described that salmon
spawning migrations toward their natal rivers was initiated and
dependant primarily on odor.
Growth Characteristics
The length and weight of chum salmon at hatching are about 22 mm and about
0.16 g respectively, while after absorption of the yolk sac they are 27 to
32 mm long and weigh about 0.20 g. In experimental situations the growth
rate of juvenile chum salmon was dependant on the concentration of food.
Growth of chum salmon stocks from various areas along the Pacific Coast from
scale analysis depends on percent weight increase declined each year as the
fish grew older. It was noted at for each age group of returning adult chum
salmon, fish from large rivers were larger than those from small streams.
The Fishery
The 1978 and 1980 commercial harvests averaged 1,151,000 fish, which is
equivalent to the high harvests in Washington State in the 1930's.
Native runs also have benefited from the hatchery enhancement program
and total chum salmon returns to Puget Sound now include a major
portion of native stocks along with hatchery returns. Odd-number years are
historically low harvest years for chum salmon. Harvest rates determined
for the terminal area fishery are based on preseason run size forecasts
(minus escapement goals), and updates of the run size throughout the season.
Although not a prime target for sport fisherman in the Pacific
Northwest, chum salmon are caught incidently by anglers
fishing for coho and chinook salmon. Chum salmon sport fisheries in
Washington State are localized primarily in southern Puget Sound.
Interest in this species as a recreational fish has been growing each year
*06*.
Life History - 3 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
Reproductive Habitat: Chum salmon spawn in waters ranging from short
coastal streams, where the adults may spawn within the tidal zone, to large
river systems, such as the Yukon River, where they are known to migrate
upstream over 2,500 km. Most spawn above the reaches of salt water and
within 200 km of the sea. Spawning grounds must provide suitable substrate
as well as suitable stream conditions. Many stocks of chum salmon
(particularly fall chum) select areas with springwater or groundwater
emergence. These areas tend to maintain water flows and temperatures warm
enough to keep from freezing during the winter months, as in the lower Delta
River southeast of Fairbanks, Alaska, where spawning occurs in several small
spring-fed channels whose fall and winter flows are composed entirely of
clear upwelling groundwater. Dewatering and freezing of salmon redds were
the most important factors contributing to the high levels of embryo
mortality found in the habitats used for incubation. These factors were
most pronounced in slough habitats that were protected from cold surface
water overtopping and where upwelling groundwater was more prevalent.
Upwelling is the most significant physical variable affecting the develoment
and survival of chum salmon embryos incubating in the slough and side
channel habitats because 1) it eliminates or reduces the likelihood of
dewatering or freezing of the substrate environment; 2) it provides a
relatively stable intragravel incubation environment, buffering it from
variations in local surface water and climatic conditions; and 3) it
increases the rate of exchange of intragravel water over the embryos, which
enhances the replenishment of dissolved oxygen and the removal of metabolic
wastes *232*.
Reproductive Seasonality: The chum salmon is typically a fall spawner. In
Alaska, they ascend the rivers from June to September, the peak spawning for
most of the northern populations occuring from July to early September and
for southern populations in October or November. Within the Yukon River
drainage, summer chum salmon spawn from July through early to mid August,
whereas fall chum salmon spawn from September through early November. On
the Alaska Peninsula, spawning occurs from August to early September *232*.
Reproductive Behavior: As with other salmon, adult chum salmon return from
the sea and 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 loose redd substrate
material downstream, and a depression 8 to 43 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, and the redd appears to move
upstream. As a result of the continued digging, the redd may grow to become
1.6 to 3.2 m long and 1.1 to 2.1 m wide. A female may spawn with several
males, and a male may mate with more than one female *232*.
Age at Sexual Maturity: The age at which chum salmon mature sexually ranges
from two to seven years, although most mature in their third to fifth year.
In general, fish from the southern part of the range return to streams
during their third and fourth years, whereas those from the Yukon (and
probably other far north rivers) return mostly in their fourth and fifth
Life History - 4 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
years. In Alaska Peninsula waters, fourth-year chum salmon are normally
predominant, followed by significant numbers of third- and fifth-year fish.
Fish in their fourth year are usually most common in Southeast Alaska.
Fifth-year fish predominate from Prince William Sound northward, with
fourth- and sixth-year fish being next in abundance. Seventh- and eight-year
fish are rare *232*.
Fecundity: Fecundity varies by stock and the size of the female and ranges
from 1,000 to 8,000 eggs. In Alaska, 2,000 to 3,000 are most common.
Samples taken from the lower Noatak River north of Kotzebue on September 1,
1981, ranged from 1,860 to 4,190 eggs and averaged 3,120 eggs, which is
larger than fecundities reported for other Alaskan chum salmon *232*.
Frequency of Breeding: As with all Pacific salmon, the spawning cycle for
chum salmon is terminal. Both male and female die after spawning *232*.
Incubation Period/Emergence: The 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 or regulate the key
factors 1, 2, and 3. The time from fertilization to hatching can range from
1.5 to 4.5 months, depending primarily on water temperature. In Alaska,
hatching of eggs occurs from December to February in the southerly parts of
the range. The time of hatching in northern Alaska is not definitely known,
although studies of spawning grounds in the Noatak River in northwestern
Alaska suggest that egg hatching occurs from late December through January.
Results of three years of study in the Delta River of Interior Alaska reveal
that hatching began in early February and was completed by mid March.
Embryos in slough and side channel habitats are influenced by warmer
upwelling water, whereas embryos in the main stem are not. The alevins
remain in the gravel until the yolk sac is absorbed, 60 to 90 days after
hatching, then make their way through the gravel and begin migration to the
sea. Although rare, chum salmon that have spent at least a year in
freshwater lakes and grown to lengths of 160 to 170 mm have been captured at
Lake Aleknagik in the Wood River system of Bristol Bay *232*.
Sizes of Use Areas: From studies of Columbia River tributaries, a
conservative figure for the number of pairs of salmon that can
satisfactorily utilize a given area of spawning gravel may be obtained by
dividing the area by four times the average size of the redds. Redd area
can by 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.
The average size of the redd area has been reported to range from 1.0 m2 to
4.5 m2. The ADF&G states that the optimum size is considered to be 3 m2.
The optimum density at which maximum egg deposition occurred ranged from 1.7
to 2.4 m2 per female chum salmon. Because of the effects of dewatering and
freezing, the amount of available habitat at the time when adult chum 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
Life History - 5 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
dewatering and freezing in various habitat types *232*.
Timing of Movements and Use of Areas: Soon after emerging from the gravel,
juvenile chum salmon begin moving to the sea. In studies of Hooknose Creek,
British Columbia, downstream migration in this relatively shallow (13 inches
deep), coastal stream is usually at night near the surface of the water and
in the center of the stream, where the currents are strongest.
Out-migrating juvenile chum salmon were captured in similar numbers at all
stations sampled across the Yukon River. The sampling location was near the
Anuk River, approximately 101 km upstream of Flat Island at the mouth of the
Yukon River. Chum salmon fry out-migrations tend to be correlated with
increased or peak water flows following spring breakup. In their first year
at sea, chum salmon migrate to offshore waters of the North Pacific Ocean
and Bering Sea. Adults return to fresh water during the period from June
through September. Rates of movement during upstream migration vary
greatly. Yukon River chum salmon migrated at 80 km per day for the first
1,300 km and 56 km per day for the next 1,100 km. In the Amur River, USSR,
the average rate of migration was 115 km per day. In some rivers of Japan
where spawning grounds are much closer to the sea, the average rate of
travel was 1.9 to 4.2 km per day. A study suggested that 37 km per day was
the best average migration rate for Yukon River fall chum salmon *232*.
Migration Routes: Rivers serve as corridors for smolt out-migration. Adult
upstream migration may be hindered or prevented by excess turbidity, high
temperatures (20.0 oC or more), sustained high water velocities (greater
than 2.44 m/sec), and blockage of streams (e.g., log jams, beaver dams, and
waterfalls). Once in the sea, the young chum salmon remain close to shore
(within 37 to 55 km of the shoreline) during July, August, and September
before dispersing into the open ocean. During this time, stocks found along
the northern coast of the Gulf of Alaska and south of the Alaska Peninsula
probably migrate westward. Stocks found north of the Alaska Peninsula
probably move to the southwest. From tagging studies, maturing Alaskan chum
salmon movements were summarized as follows: Maturing chums of western
Alaskan origin occupy the entire Gulf of Alaska in spring and were found
westward along the Aleutians to 179 deg E. There was no tagging evidence of
the presence of Alaskan chums in the Bering Sea before June. The recovery
in the Yukon River of a maturing fish tagged in July at 60 deg N, 174 deg E,
not far from the USSR coast, constitutes the westernmost record of a north
American chum salmon, as revealed by tagging. Other chums, tagged in the
Gulf of Alaska, were found to travel as far north as the Arctic Ocean. The
direction of movement in the Gulf of Alaska is westward in April-June. In
the latter month most of the fish pass through the eastern part of the
Aleutian Chain and migrate rapidly northward in the Bering Sea. No
significant penetration of the Bering Sea by immature fish (from the Gulf of
Alaska) was disclosed. Maturing chum salmon originating in central and
southeastern Alaska occupy a large part of the Gulf of Alaska in spring but
were rarely found west of 155 deg W. From May to July the fish tend to
shift northward into waters from which western Alaska chums have largely
withdrawn. Some immature fish move westward along the Aleutians to at least
177 deg W. No significant penetration of the Bering Sea by immature or
maturing fish was indicated *232*.
Natural Factors Influencing Populations: The period the eggs and alevin
Life History - 6 (DRAFT) - Life History
Species salmon, chum
Species Id M010003
Date 26 AUG 96
spend in the gravel is a time of heavy mortality. The survival rate from
eggs to fry in natural streams averages less than 10%. Young chum salmon on
the spawning grounds and during downstream migration are preyed upon by
cutthroat and rainbow trout, Dolly Varden, coho salmon smolts, sculpins,
kingfisher, merganser, other predaceous birds, and mammals. Even stonefly
larvae and possibly other predaceous insects may prey on eggs and alevins.
Water temperature, floods, droughts, other fluctuations in water level,
spawning competition, and poor returns of adults, control number of young to
a far greater extent. There is often heavy predation on eggs of spawning
fall chum salmon by arctic grayling and mallard ducks in such Yukon River
drainage systems as the Delta, Sheenjek, and Toklat rivers. A study
documents the die-off of prespawn adult chum salmon in Porcupine Creek on
Etolin Island in southeast Alaska. The fishes' migration route to spawning
areas was blocked at the intertidal stream reach by low stream flow and neap
tides. Withing four days, about 3,000 pink and chum salmon had collected in
a large pool in the intertidal reach of the stream. The crowded fish
lowered the dissolved oxygen level to less than 2 mg/l, and some salmon
began to die in the center of the pool. At sea, chum salmon are preyed upon
by marine mammals, lampreys, and, in the early sea life, possibly by large
fishes. Upon returning to fresh water to spawn, adults fall prey to bears,
eagles, osprey, and other mammals *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;
reduction in food supply; reduction in protective cover (e.g., overhanging
stream banks or vegetation); shock waves in aquatic environment; and human
harvest *232*.
LIFE HISTORY CODES -
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Breeding/Spawning Season: October
Breeding/Spawning Season: November
Mating System (Single breeding season): Promiscuity (
Spawning Site: Gravel
Spawning Site: Rocks
Nest Materials: Gravel
Gestation/Incubation Period: 1-2 months
Gestation/Incubation Period: 3-4 months
Average Number of Offspring/Reproductive Effort: 101-
Average Number of Offspring/Reproductive Effort: 1,00
Spawning Site: Flowing Water
REFERENCES FOR LIFE HISTORY- 06 and 232
Life History - 7 (DRAFT) - Management Practices
Species salmon, chum
Species Id M010003
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Regulating harvest of species being described
Existing Stocking captive-reared wild-strain animals
Existing Put-and-take stocking
Existing Regulating harvest - setting bag/creel limits
Existing Regulating commercial harvest levels
Existing Other management practices [specified in comments]
Beneficial Developing/maintaining suitable salinity
Adverse Salinity alteration
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
Beneficial Regulating harvest of species being described
Beneficial Other management practices [specified in comments]
Adverse Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 232
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 232
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 06
COMMENTS ON MANAGEMENT PRACTICES -
The freshwater, estuarine, early marine life stages appear to be critical
for this species.*255*
The chum salmon is an important component of the commercial fishery from
Washington northward along the Pacific Coast. The major chum salmon fishery
is centered in Southeast Alaska and British Columbia. The total commercial
salmon catch north of Bristol Bay, Alaska, consists primarily of chum
salmon and provides income for many villagers in western Alaska (Hale 1981).
Chum salmon stocks in Washington State increased greatly in the
mid-1980's because of a massive enhancement program; Hood Canal and the
rivers that flow into it were managed principally for the production of chum
salmon (Bax et al. 1979; Whitmus and Olsen 1979). Chum salmon production in
Washington State has increased, in part due to increased management effort
on this species.
The 1978 and 1980 commercial harvests averaged 1,151,000 fish, which is
equivalent to the high harvests in Wasington State in the 1930's.
Native runs also have benefited from the hatchery enhancement
program, and total chum salmon returns to Puget Sound now include a major
portion of native stocks along with hatchery returns. Odd-number years are
historically low harvest years for chum salmon. Harvest rates determined
for the terminal area fishery are based on preseason run size forecasts
(minus escapement goals), and updates of the run size throughout the season.
Although not a prime target for sport fisherman in the Pacific Northwest
chum salmon are caught incidently by anglers fishing for coho and chinook
Management Practices - 1 (DRAFT) - Management Practices
Species salmon, chum
Species Id M010003
Date 26 AUG 96
salmon. Chum salmon sport fisheries in Washington State are localized
primarily in southern Puget Sound. Interest in this species as a
recreational fish has been growing each year. *06*
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; reduciton in food supply; reduction in protective cover (e.g.,
overhanging stream banks or vegetation); shock waves in aquatic environment;
and human harvest *232*.
Management Practices - 2 (DRAFT) - References
Species salmon, chum
Species Id M010003
Date 26 AUG 96
References
6 * Pauley, G., K. Bowers, G. Thomas. 1988. Species Profiles: Life
Histories and Environmental Requirements of Coastal Fishes and
Invertebrates (Pacific Northwest)--Chum Salmon. U.S. Fish and
Wildlife Service Biol. Rep. 82(11.81) pp 17.
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.
255 * Monaco, M.E., R.L. Emmett. 1988. National Estuarine
Inventory: Estuarine Living Marine Resources Project Washington
State Component. Living Marine Resources Program (ed.). National
Oceanic and Atmospheric Administration Rockville, MD:82.
References - 1