Coho salmon (Oncorhynchus kisutch)
(Fertilized Egg)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
959 Phys. Assoc. Optimum 660 629
Details
Gravel and small-rubble substrate with low amounts of fine sediments are
optimum for survival, growth, and development of embryos and alevins and
for later emergence of fry.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
960 Western U.S. Phys. Assoc. Example 661 629
and Canada
Details
Redds with 1.3-10.2-cm diameter substrate sizes and a low percentage of
fines results in high survival of substrate sizes. A low percentage of fines
result in high survival of embryos.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
962 Oxygen Requirement ³8 mg/l 641 629
Oxygen Limit £6.5 mg/l 664
Oxygen Lethal £3 mg/l 644
Details
DO concentration ³8 mg/l are required for high survival and emergence of
fry. Embryo survival drops significantly at levels £6.5 mg/l. Concentrations
<3 mg/l are lethal.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
963 Western U.S. Oxygen Tolerate 5 mg/l to 661 629
and Canada Saturation
Details
- DO concentrations at or near saturation (with temporary reductions no lower
than 5 mg/l) are recommended as criteria necessary for successful reproduc-
tion of anadromous salmonids.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
966 Temperature Optimum 4.4°13.3°C 630 629
661
Details
Temperatures ranging from 4.4°-13.3°C are considered optimum for embryo
incubation. Embryo survival decreases if these thresholds are exceeded.
Coho salmon (Oncorhynchus kisutch)
(Juvenile)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
949 Light Limit 658 629
Temperature Limit 650
Water Motion Limit 640
639
Details 668
Photoperiod, temperature, and flow are especially critical environmental
factors that influence smoltification.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
955 - Oxygen Limit <6.5 mg/l 643 629
Movement Example
Details
Maximum sustained swimming speed of coho is sharply reduced at DO levels
<6.5 mg/l at all temperatures.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
956 Oxygen Avoid <4.5 mg/l 123 629
Details
Juveniles avoid waters with DO concentrations <4.5 mg/l.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
967 Phys. Assoc. Optimum - 629 -
Details
Coho parr are most abundant in large, deep pools where they congregate near
instream and overhead cover (on banks) of logs, roots, debris, undercut banks,
and overhanging vegetation.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
968 Oregon Phys. Assoc. Optimum 1113 629
Details
Studies in Oregon suggest that pools of 10-80 cu. m or 50-250 cu. m (with
sufficient riparian canopy for shading) are optimum for coho salmon
production.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
969 Phys. Assoc. Optimum 1113 629
Details
A pool-to-riffle ratio of 1:1 provides optimum food and cover conditions for
coho parr.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
972 Area of Water Characteristic 657 629
Details
Beaver ponds and quiet backwater areas (often some distance from the main
stream channel and dry during summer low-flow periods) are also utilized
as winter habitat.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
973 Oregon Water Motion Limit 655 629
Details
Lowest returns of adult coho salmon coincide with low summer flows coupled
with high winter floods.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
974 California Water Motion Limit 636 629
Details
Highest mortality of coho and other salmonids in the summer occurred during
periods of lowest flows.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
975 British Columbia Water Motion Optimum 620 629
656
Details
Stabilization of winter flows and increases in summer flows have led to
increased production of coho salmon.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
976 Phys. Assoc. Optimum 657 629
Details
Stream enhancement techniques aimed at reducing displacement downstream
during winter floods and at providing deep pools during summer low flows,
could substantially increase stream-rearing capacity for coho salmon.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
977 Oxygen Optimum >5 mg/l 649 629
Oxygen Limit <3 mg/l 632
Details
Growth rate and food-conversion efficiency of coho fry are optimum at DO
concentrations above 5 mg/l. Below 4.5 mg/l, growth rate and food conversion
rapidly decrease to the point where growth ceases or is negative (<3 mg/l).
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
978 Oxygen Limit £6 mg/l 642 629
Details
Swimming speed decreases below the saturation level, especially <6 mg/l.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
979 Oxygen Avoid <4.5 mg/l 123 629
Details
DO concentrations <4.5 mg/1 are avoided.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
981 Temperature Limit >20°C 646 629
Details
Significant decreases in swimming speed occur at temperatures >20°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
982 Temperature Limit 20.3°C 630 629
Details
Growth ceases at temperatures >20.3°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
983 Oregon Temperature Optimum 9°13°C 666 629
Temperature Limit 18°C
Details
The growth rate of coho fry was high in the 9°-13°C temperature range, but
slowed considerably at temperatures near 18°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
984 Washington State Phys. Assoc. Limit 617 629
Details
Reduced coho biomass has been found in stream sections where the canopy
was very dense.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
986 Western U.S. Phys. Assoc. Optimum 661 629
and Canada Temperature Optimum 10°-15°C
Oxygen Optimum Near Saturation
Details
In summer, optimum rearing habitat for coho parr consists of a mixture of
pools and riffles, abundant instream and bank cover, water temperatures that
average 10°-15°C in the summer, DO near the saturation level, and riffles
with low amounts of fine sediment.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
987 Phys. Assoc. Example 657 629
Details
Streamside vegetation is an important component of coho habitat because it
provides food, cover, temperature control, and bank stabilization.
Coho salmon (Oncorhynchus kisutch)
(Larva)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
947 - Area of Water Characteristic 652 629
666
Details
Newly emerged fry aggregate along stream margins, in shallow pools, and
in backwaters and eddies.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
948 California Competitors Characteristic 663 629
Phys. Assoc. Characteristic
Details
Fry gradually move into deeper pools where they become aggressive and
territorial. Fry unable to hold territory emigrate downstream or
elsewhere in the stream system.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
959 Phys. Assoc. Optimum 660 629
Details
Gravel and small-rubble substrate with low amounts of fine sediments are
optimum for survival, growth, and development of embryos and alevins and
for later emergence of fry.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
961 Phys. Assoc. Example 629 -
Details
Emergence of coho fry was high at <5% fines, but dropped sharply at
³15% fines.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
962 Oxygen Requirement ³8 mg/l 641 629
Oxygen Limit £6.5 mg/l 664
Oxygen Lethal £3 mg/l 644
Details
- DO concentration ³8 mg/l are required for high survival and emergence of
fry. Embryo survival drops significantly at levels £6.5 mg/l. Concentrations
<3 mg/l are lethal.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
970 Phys. Assoc. Optimum 662 629
Details
The greatest number of coho salmon fry remained in stream channels
consisting of 50% pools and 50% riffles. Numbers of fry remaining in
channels of either 100% pools or 100% riffles could be 39% and 20%
lower, respectively.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
971 Temperature Example 648 629
Movement Example 637
Water Motion Example
Phys. Assoc. Example
Details
As water temperatures decrease below 9°C, coho salmon fry become less
active and seek deep (³45 cm), slow (<15 cm/sec) water in or very near
(<1 m) dense cover of roots, logs, and flooded brush.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
980 Temperature Lethal 22.9°25.0°C 631 629
Details
Upper incipient lethal temperatures for coho fry range from 22.9°-25.0°C
(acclimation temperatures of 5°-23°C).
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
985 Oregon Phys. Assoc. Avoid 659 629
Details
Coho fry appear to avoid areas of dense shade. This suggests that a stream
canopy enclosing >90% of the sky may exceed the optimum level.
Coho salmon (Oncorhynchus kisutch)
Lake Erie (Non-spawning Adult)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
136 Pred/Prey Characteristic 19 -
Details
Coho salmon feed extensively on emerald shiners and smelt.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
796 Movement Example 19 -
Details
Coho salmon migrate to deep, cold waters along the Canadian shore during
summer.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
797 Pred/Prey Example 19 -
Details
Little information exists on the effects of coho salmon on resident fish
populations. However, it is known that coho salmon feed extensively on
emerald shiners and smelt.
Coho salmon (Oncorhynchus kisutch)
(Non-spawning Adult)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
952 Temperature Limit ³12.7°C 645 629
651
647
Details
Disease infection rates in coho salmon increase markedly at temperatures
³12.7°C.
Coho salmon (Oncorhynchus kisutch)
(Spawning Adult)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
950 Depth Limit ³0.18 m 667 629
Water Motion Optimum 244 cm/s
Details
Successful upstream migration of adult coho salmon are a minimum depth of
0.18 m and a maximum velocity of 244 cm/sec.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
951 Temperature Lethal ³25.5°C 630 629
Details
Temperatures ³25.5° are lethal to migrating adults.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
953 Temperature Optimum £13°C 629 -
Details
Temperatures £13°C have been recommended to minimize prespawning
mortality of coho salmon during upstream migration.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
954 Oxygen Optimum >6.3 mg/l 644 629
Details
DO levels >6.3 mg/l are recommended for successful upstream migration
of anadromous salmonids.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
957 Columbia River Phys. Assoc. Characteristic 635 629
633
Details 663
- Coho salmon construct redds in swift, shallow areas at the head of riffles.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No. 958 Oregon Water Motion Prefer 2170 cm/s 596 629
Depth Prefer ³15 cm
Details
Preferred redd construction sites in riffle areas have velocities of 21-
70 cm/sec and minimum depths ³15 cm.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
964 Oregon Temperature Example 2.5°12.0°C 635 629
Details
Coho salmon were observed spawning in Oregon at 2.5°-12.0°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
965 Temperature Optimum 4.4°9.4°C 630 629
Details
Temperatures of 4.4°-9.4°C are considered suitable for spawning.