Brown trout (Salmo trutta)
(Fertilized Egg)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
275 Area of Water Example 325 109
Depth Example
Details
- When spawning was in the deeper parts of the river, survival of eggs and fry
was negligible compared to spawning in small streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
276 Temperature Example 405 109
400
Details
Brown trout egg development to hatching takes 165 days at 1.5°C, 148 days
at 1.9°C, 120 days at 2.9°C, 95 days at 5°C, 66 days at 7°C, 59 days at
7.9°C, 46 days at 9.2°C, 38 days at 10.7°C, and 33 days at 11.2°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
277 Temperature Example 332 109
Details
Normal brown trout development occur up to 10°C, compared to 13°C for
rainbow trout. Fingerling brown trout grew best at 13°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
278 Wood Fiber Limit 346 109
Details
Wood pulp fiber reduced hatching of brown trout eggs from 98% at 60 ppm
to 24% at 250 ppm.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
843 Water Motion Limit 594 555
Water Level Limit
Details
Significant mortalities to salmonid embryos and yolk-sac fry have been reported
from freezing of redds caused insufficient flow in winter. Redd destruction is
also caused by gravel movement and displacement of newly emerged fry during
abnormally high freshets.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
866 Pigeon River, Temperature Example 557 555
Michigan 586
Details
In northern temperate areas, cold, well-oxygenated, groundwater seepage may
be important to successful spawning and incubation of brown trout, because
uniform water temperatures are ensured from year to year.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
878 Temperature Optimum 7°12°C 568 555
Details
The optimal temperature range for brown trout egg development, hatching
success, and fry emergence was 7°C-12°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
879 Temperature Optimum 6.6°12.8°C 332 555
Details
The optimal temperature range for brown trout egg development, hatching
success, and fry emergence was 6.6°-12.8°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
880 Temperature Optimum 5°13°C 568 555
Details
The optimal temperature range for brown trout egg development, hatching
success, and fry emergence was 5°-13°C for the embryo stage.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
881 Temperature Optimum 2°13°C 555 -
Temperature Tolerate 0°15°C
Details
Optimal incubation temperatures are assumed to be 2°-13°C, with a tolerance
range of 0°-15°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
882 Oxygen Lethal <4.5 ppm 400 555
CO2 Lethal >22 ppm
Details
Brown trout egg development ceased at dissolved CO2 concentrations >22 ppm
and DO levels <4.5 ppm.
Brown trout (Salmo trutta)
(Juvenile)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
266 Competitors Limit 282 109
352
Details
Competition between brown trout and atlantic salmon parr did not affect
trout growth.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
277 Temperature Example 332 109
Details
Normal brown trout development occurred up to 10°C, compared to 13°C for
rainbow trout. Fingerling brown trout grew best at 13°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
280 Movement Characteristic 378 109
Details
Brown trout smolts migrate to the lake or ocean (in relation to size rather
than age), but usually after 23 years.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
281 England Movement Characteristic 395 109
Light Characteristic Night
Details
Downstream brown trout movement usually at night.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
282 Movement Example 301 109
Details
Many brown trout young migrated to the lake from streams, and returned to
the streams as yearlings.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
283 Movement Characteristic * 109
Temperature Example
Details
In lakes, brown trout leave littoral zones for deeper water in April-June when
surface temperatures reach ~12°C. Older trout usually move earlier than
young trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
285 Pred/Prey Characteristic 306 109
Temperature Example
Water Motion Example
Phys. Assoc. Characteristic
Details
Brown trout fingerlings fed on Simulium, Ephemeroptera, and Plecoptera in the
summer (usually in the current). During winter they usually remained under the
bank overhang and fed on Gammarus and Asellus.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
290 Pred/Prey Example 298 109
Details
Fish (particularly small rainbow trout) were the principal foods of brown trout
in a Colorado reservoir.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
291 Pred/Prey Characteristic 109 -
Details
In lakes, chironomids, Gammarus, and surface insects are the principal foods
for smaller trout. Fish are the principal foods of larger trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
363 Wisconsin Pred/Prey Example 360 109
Details
Rainbow trout were more susceptible to pike predation than were brown trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
827 California Area of Water Example 590 555
Pred/Prey Example
Details
Small brown trout feed heavily on zooplankton in lakes. They gradually switch
from bottom-dwelling insect larvae and amphipods to fish at lengths >25 cm.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
892 Phys. Assoc. Prefer 555 -
Details
Brown trout fry prefer pools and rocky substrates. They are often excluded from
these areas by older and larger juvenile trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
900 Temperature Optimum 19°C 602 555
Details
Maximum growth during the summer for juvenile brown trout is 19°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
901 Temperature Optimum 7°19°C 568 555
Temperature Optimum 12°C 562
Details
Good brown trout growth was 7°-19°C. Optimal growth was 12°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
902 Temperature Prefer 17.6°C 108 555
Details
- Brown trout juveniles showed a preference for 17.6°C in a laboratory
experiment.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
903 Europe Temperature Lethal 29°C 597 555
Details
The mean, upper, short-term lethal temperature for streamresident brown
trout juveniles was 29°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
904 Oxygen Lethal 1.62.8 ppm 565 555
at 9°21°C
Details
Deaths of brown trout juveniles first occurred at DO concentrations of 1.6-2.8
ppm at temperatures of 9°-21°C. Death occurred at 1.5-2.5 ppm for 50% of the
juveniles, and 100% were dead at 1.3-2.3 ppm DO. Juvenile brown trout were
asphyxiated in 1.5 min. at 19.1°C, 1.94 ppm DO, and 39 ppm CO2.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
905 Oxygen Lethal 1.42 ppm 249 555
at 9.4°C
Oxygen Lethal 2.53 ppm
at 20.5°C
Details
Mean lethal DO levels ranged from 1.42 ppm at 9.4°C to 2.53 ppm at 20.5°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
906 Depth Characteristic 555 -
Water Motion Characteristic
Details
Juvenile brown trout are found at shallower depths and lower velocities than
adults.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
907 Water Motion Prefer <15 cm/s 628 555
Details
Both fry and juvenile brown trout prefer velocities of <15 cm/s.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
908 Depth Prefer ³15 cm 628 555
Details
As growth progresses, >15 cm depths are preferred.
Brown trout (Salmo trutta)
(Larva)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
269 Temperature Lethal 413 109
Details
Tests with sac fry acclimated at 5°-6°C indicated that 22°C was the lethal
limit for 50% of the fry in seven days. When sac fry were acclimated to 10°-
20°C, the lethal limit was 23°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
275 Area of Water Example 325 109
Depth Example -
Details
When spawning was in the deeper parts of the river, survival of
eggs and fry was negligible compared to spawning in small streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
284 Pred/Prey Characteristic 306 109
319
Details
Brown trout fingerlings start feeding on minute bottom fauna (not plankton)
after the yolk sac is lost.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
843 Water Motion Limit 594 555
Water Level Limit
Details
Significant mortalities to salmonid embryos and yolk-sac fry have been reported
from freezing of redds caused by insufficient flow in winter. Redd destruction
is also caused by gravel movement and displacement of newly emerged fry during
abnormally high freshets.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
883 Danish Brook Movement Characteristic 589 555
Details
Brown trout fry dispersal takes place immediately after emergence.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
884 Competitors Characteristic 578 555
587
Details
Brown trout fry are aggressive from the first day of emergence, and territories
are established in running waters.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
885 Temperature Optimum 7°12°C 568 555
Details
The optimal temperature range for freefeeding brown trout fry was 7°-12°C.
The optimum temperature for feeding onset was 10°-12°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
886 Virginia Temperature Optimum 7°15°C 562 555
Details
- The overall optimum temperature was 7°-15°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
887 Temperature Optimum 12.8°C 332 555
Details
After feeding began, brown trout growth was optimum at 12.8°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
888 Temperature Lethal <4.5°C 332 555
Details
Heavy brown trout fry mortality occurred at temperatures <4.5°C after
emergence from the gravel.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
889 Temperature Optimum 6.7°12.8°C 332 555
Details
An optimal temperature of 6.7°-12.8°C was proposed.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
890 Europe Temperature Lethal 25.46°C 597 555
Details
The mean upper lethal temperature for brown trout fry was 25.46°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
891 Temperature Example - 249 555
Oxygen Lethal 2.3 ppm
CO2 Lethal 14 ppm
Details
Brown trout fry asphyxiated quickly at 10.8°C with 2.3 ppm DO and 14 ppm
CO2.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
892 Phys. Assoc. Prefer 555 -
Details
Brown trout fry prefer pools and rocky substrates. They are often excluded
from these areas by older and larger juvenile trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
893 Phys. Assoc. Characteristic 577 555
Details
Brown trout fry have been consistently found at the edge of riffles.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
894 River Indalsalver Area of Water Example 579 555
Depth Example 2030 cm
Phys. Assoc. Example
Water Motion Example
Details
Brown trout fry have been found at river margins in sections of water 20-30 cm
deep. Fry were rarely found in still, muddy backwaters or in areas with a small
gravel substrate.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
895 Phys. Assoc. Requirement 588 555
Details
Clearing weeds, branches, twigs, and larger stones from a stream bed resulted
in high brown trout fry mortality.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
896 Phys. Assoc. Prefer 555 -
Details
Brown trout fry prefer a rocky substrate.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
897 Phys. Assoc. Characteristic 572 555
Details
During the winter, brown trout fry bury themselves in the stony substrate of
streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
907 Water Motion Prefer <15 cm/s 628 555
Details
Both fry and juvenile brown trout prefer velocities of <15 cm/s.
Brown trout (Salmo trutta)
(Non-spawning Adult)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
262 Light Example 415 109
Details
Brown trout growth was more rapid with <12 hours of light/day.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
263 Light Example - 296 109
Details
There is little correlation between photoperiod and growth.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
264 California Dissolved Example - 310 109
Solids
Details
Brown trout growth was correlated with total dissolved solids, but not with
food supply.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
265 Pennsylvania Conductivity Example 336 109
Details
A high correlation was found between brown trout growth and water
conductivity.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
267 Water Level Example 380 109
Details
Increasing the water level of Haweswater by 11.6 m was followed by a
considerable increase in brown trout growth rate.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
268 Temperature Lethal 300 109
Details
The upper critical temperature for acclimated brown trout at 5°C was 22.5°C,
at 10°C was 24.2°C, at 20°C was 24.8°C. The ultimate temperature limit
was 25.3°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
270 Temperature Lethal 353 109
297
Details
The upper instantaneous lethal temperature differed with brown trout age and
season. The temperatures were 27°29°C in summer and 25°27°C in autumn.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
271 Oxygen Limit 353 109
Details
Minimum oxygen was 4.5 mg/l in winter and 2.53.0 mg/l in summer.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
272 Oxygen Limit 297 109
Details
Minimum oxygen was 2 mg/l in summer.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
283 Movement Characteristic * 109
Temperature Example
Details
In lakes, brown trout leave littoral zones for deeper water in April-June
when surface temperatures reach ~12°C. Older trout usually move earlier
than young trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
286 Light Characteristic 416 109
Details
Brown trout are active and feed more at night than in daylight. They also
feed throughout the winter.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
287 Movement Characteristic 290 109
Area of Water Example 540
Light Characteristic
Details
Brown trout in lakes showed more activity during the day than at night (with most
activity at dawn). They were also more active in May/June (or in June and
August) than at other times of the year.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
288 Pred/Prey Characteristic 109 -
Area of Water Example
Details
In streams, brown trout fed on bottom fauna, insects, and amphipods (with
some terrestrial insects).
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
289 Sweden Area of Water Example 323 109
Water Motion Example
Details
Impoundment of streams resulted in Entomostraca and terrestrial insects
becoming more important in the brown trout diet.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
290 Pred/Prey Example 298 109
Details
Fish (particularly small rainbow trout) were the principal foods of brown trout
in a Colorado reservoir.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
291 Pred/Prey Characteristic 109 -
Details
In lakes, chironomids, Gammarus, and surface insects are the principal foods
for smaller trout. Fish are the principal foods of larger trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
363 Wisconsin Pred/Prey Example 360 109
Details
Rainbow trout were more susceptible to pike predation than were brown trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
822 Area of Water Example 593 555
Pred/Prey Characteristic
Details
In rivers and streams, brown trout (up to 25-30 cm long) are sizeselective
feeders usually selecting larger prey.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
823 Pred/Prey Characteristic 555 -
Details
Brown trout generally feed on terrestrial and aquatic insects (Ephemeroptera,
Trichoptera, and Plecoptera). As brown trout exceed 25 cm, a fish and
crustacean diet become more important.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
824 Light Characteristic 585 555
Pred/Prey Characteristic
Details
Mature brown trout are active night feeders.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
825 Pred/Prey Characteristic 333 555
Ice Example
Details
Brown trout are occasionally active throughout the winter and periodically
feed even in frazil ice.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
826 Area of Water Example 540 555
Light Optimum Dawn 290
Details
- In lakes, brown trout may be more active during the day than at night. Most
brown trout activity is at dawn.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
828 Great Lakes Pred/Prey Limit 556 555
Details
Members of the genus Alosa are a major brown trout forage fish in the Great
Lakes.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
835 Phys. Assoc. Optimum 555 -
Area of Water Example River
Details
Optimal brown trout riverine habitat is characterized by clear, cool-to-cold
water; a relatively siltfree rocky substrate in rifflerun areas; a 50%-70%
pool to 30%-50% rifflerun habitat combination with areas of slow, deep water;
well-vegetated, stable stream banks; abundant instream cover; and relatively
stable annual water flow and temperature regimes. Brown trout tend to
occupy the lower reaches of low- to moderate-gradient areas (<1%) in suitable,
high-gradient river systems.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
836 Phys. Assoc. Optimum 555 -
Area of Water Example Lake
Details
Optimal lacustrine brown trout habitat is characterized by clear, cool-to-cold,
deep lakes that are typically oligotrophic. They may vary in size and chemical
quality, particularly in reservoir habitats. Brown trout normally are stream
spawners and require tributary streams with gravel substrate in rifflerun areas
for optimal reproduction to occur.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
837 Water Motion Limit 555 -
Details
High-gradient, headwater trout streams are relatively unproductive.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
838 Wyoming Nitrogen Optimum 0.150.25 mg/l 559 555
Details
Late-summer, nitratenitrogen measurements in Wyoming were correlated
with habitat productivity and trout standing crops. Optimal levels were
0.15-0.25 mg/l.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
839 Area of Water Characteristic 555 -
Details
When different trout species occur in the same high-gradient river systems,
they tend to occupy the suitable trout habitat in a longitudinally strati-
fied manner from headwater areas downstream. Brook or cutthroat trout
tend to occupy colder, swifter, less-fertile headwater regions; rainbow
trout occupy the midregion of a river system with intermediate habitat
conditions; and brown trout occupy the deeper, lower-velocity, warmer,
more-fertile downstream region.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
840 Phys. Assoc. Example 555 -
Details
Canopy cover (shade) is important in small, brown trout streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
841 Phys. Assoc. Example 555 -
Details
Shading becomes less important as stream size increases. The greater volume
and depth of larger streams help compensate for the relative lack of shade.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
842 United States Phys. Assoc. Optimum 555 -
Details
Midday shade (50% to 75%) was assumed optimal for most small, brown trout
streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
844 Area of Water Example Streams 591 555
Temperature Limit 27.2°C
Details
The upper-limiting, near-lethal water temperature for brown trout is 27.2°C.
Naturally-reproducing, viable stream populations would not be maintained at
this temperature.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
845 Temperature Optimum 12°19°C 568 555
587
Details 562
Optimal temperature requirements for good brown trout growth and survival 602
are 12°-19°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
846 Convict Creek, Temperature Tolerate 0°27°C 333 555
California 587
Details
Brown trout have a temperature tolerance range of 0°-27°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
847 Temperature Example 591 555
Phys. Assoc. Example
Details
Absolute temperature and thermal constancy determine habitat suitability.
Streams with heavy shade or many cool springs have relatively constant
temperatures and high rates of brown trout growth.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
848 Temperature Limit 606 555
Pred/Prey Limit
Details
Water temperature and available food are interrelated and limiting in the
winter.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
849 Oxygen Optimum ³9 mg/l at 555 -
£10°C
Oxygen Optimum ³12 mg/l at
>10°C
Details
Optimal oxygen levels for brown trout are not well documented, but appear to
be ³9 mg/l at £10°C and ³12 mg/l at >10°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
850 Lake Powell, Oxygen Avoid <5 mg/l at 584 555
Utah ³10°C
Details
In the summer (³10°C), trout generally avoid water with DO levels <5 mg/l.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
851 Oxygen Lethal £3 mg/l 249 555
565
Details
The incipient lethal level of DO for adult and juvenile brown trout is ~3 mg/l
or less. The lethal level depends on environmental conditions, usually
temperature.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
852 Oxygen Lethal 555 -
Depth Example
Temperature Example
Details
Oxygen depletion occurs in some lakes, possibly resulting in winterkill of trout.
These lakes are usually shallow and snow covered with a high volume of
organic materials.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
853 Ontario pH Characteristic 5.09.5 583 555
587
Details 573
Brown trout occur within a pH range of 5.0-9.5.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
854 - pH Optimum 6.87.8 573 555
Details
Optimal growth occurs within a pH range of 6.8-7.8.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
855 pH Optimum 606 555
Details
Faster growth and greater longevity are reported for brown trout in alkaline
water than in acidic water.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
856 Depth Optimum >15 cm 628 555
Water Motion Optimum <15 cm/s
Details
A water depth ³15 cm and a focal-point velocity of <15 cm/s are recommended
for optimal adult brown trout resting and feeding habitat.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
857 Phys. Assoc. Characteristic 555 -
Depth Characteristic
Water Motion Characteristic
Details
Cover for adult brown trout consists of areas of obscured stream bottom where
the velocity is low in water at least 15 cm deep.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
858 Depth Example 628 555
Details
- In larger streams, brown trout abundance ³15 cm in length increased
with depth. Most brown trout were in water ³15 cm deep.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
859 Au Sable River, Depth Prefer 564 555
Michigan Light Example
Details
- In the Au Sable River, Michigan, adult brown trout preferred cover at lower
water-column depth to cover nearer the surface, cover with tactile stimulus,
and cover with less light.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
860 Phys. Assoc. Optimum 555 -
Details
A cover area of ³35% of the total stream area provides adequate cover for
adult brown trout. Summer cover is mainly to avoid predators and resting.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
862 Movement Characteristic 555 -
Depth Characteristic
Temperature Characteristic
Water Motion Characteristic
Details
- Adult brown trout tend to move into deep low-velocity water in winter.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
863 New Zealand Movement Characteristic - 1108 555
1109
Details 1110
- Adult brown trout (except during the spawning season) occupy the same
stations with very little movement to other stream sections.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
892 - Phys. Assoc. Prefer - 555 -
Details
- Brown trout fry prefer pools and rocky substrates. They are often excluded from
these areas by older and larger juvenile trout.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
906 - Depth Characteristic - 555 -
Water Motion Characteristic -
Details
- Juvenile brown trout are found at shallower depths and lower velocities than adults.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
909 Area of Water Optimum 555 -
Details
Optimum pool size for brown trout is large and deep. Pool depth and size are
sufficient to provide a low-velocity resting area for adult trout. More than
30% of the pool bottom is obscured because of depth; surface turbulence; or
logs, debris piles, boulders, or overhanging banks and vegetation. The greatest
pool depth is ³1.5 m in streams £5 m wide or ³2 m deep in streams >5 m wide.
The next most-optimum pool size is of moderate size and depth. Pool depth
and size are sufficient to provide a low-velocity resting area for adult trout.
Because of surface turbulence, depth, or the presence of structures, 5%-30% of
the bottom is obscured. Typical secondclass pools are large eddies behind
boulders with low-velocity and moderately-deep areas beneath overhanging banks
and vegetation. Least-desirable pools are small or shallow, or both. These pool
depths and sizes provide a low-velocity resting area for adult trout. Cover, if
present, may be shade, surface turbulence, or very limited structures. Typical
thirdclass pools are wide, shallow, reduced-velocity areas of streams or small
eddies behind boulders (virtually the entire bottom of the pool is discernible).
Brown trout (Salmo trutta)
(Spawning Adult)
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
273 Light Example 394 109
Details
Controlled light periodicity resulted in brown trout spawning a month early,
but with smaller eggs.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
274 Scotland Water Motion Example 328 109
Details
Brown trout spawning runs were stimulated by an increase in water flow.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
275 Area of Water Example 325 109
Depth Example
Details
- When spawning was in the deeper parts of the river, survival of eggs
and fry was negligible compared to spawning in small streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
279 Area of Water Characteristic 109 -
Details
Brown trout (lakes and ocean) spawn in streams.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
829 Area of Water Characteristic 555 -
Details
Brown trout are typically stream spawners.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
830 Movement Example 598 555
603
Details
Homing of spawning brown trout to specific natal streams (with a high degree
of accuracy and a low incidence of straying) has been confirmed.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
831 Movement Characteristic 555 -
Area of Water Example
Details
Brown trout generally move upstream in the fall to spawn or (in the case of
lakes and reservoirs) into tributary streams. Females build nests (or redds)
in the spawning gravel, and demersal eggs are deposited and covered with
gravel. After the spawning period, nests are left unguarded.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
832 Water Motion Characteristic 560 555
Details
Brown trout usually spawn in running water with some successful spawning
over seepage areas of lakes.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
833 Phys. Assoc. Requirement 555 -
Details
Adequate spawning habitat to support abundant trout population appears to
be ~5% of the total trout habitat utilized in a river system (an area equal to
~3% of the lake surface area).
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
834 Movement Characteristic 555 -
Light Characteristic
Movement Characteristic
Temperature Characteristic
Details
Brown trout spawning migrations appear to be triggered by decreasing day
length, increased late-fall flows, or drops in water temperature to <9°C.
These events are usually concurrent.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
864 Movement Characteristic 568 555
Temperature Characteristic 6°7°C 587
Temperature Characteristic 6.0°12.8°C
Details
Fall brown trout spawning migrations begin at water temperatures of 6°-7°C
or 6.0°-12.8°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
865 Southwestern Temperature Characteristic 7°9°C 581 555
Ontario
Details
Brown trout spawning occurs at 7°-9°C.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
866 Pigeon River, Temperature Example 557 555
Michigan 586
Details
In northern temperate areas, cold well-oxygenated, groundwater seepage may
be important to successful spawning and incubation of brown trout, because
uniform water temperatures are ensured from year to year.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
867 Pigeon River, Water Motion Characteristic 557 555
Michigan
Details
Potential brown trout spawning sites are characterized by water upwelling
through the gravel or by the presence of water currents flowing downward
into the gravel.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
868 Temperature Avoid 571 555
Oxygen Avoid
Details
Brown trout avoid areas of increased stream temperature or decreased DO
content.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
869 Phys. Assoc. Characteristic 587 555
574
Details 592
Brown trout spawning sites are often located at the head of riffle areas or the
tail of pools where gravel slopes gently upward.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
871 Phys. Assoc. Prefer 555 -
Details
Brown trout prefer gravel with a diameter of ~1-7 cm for spawning substrate,
but utilize gravel from 0.3-10.0 cm. Maximum gravel size is dependent on the size
of the spawning female.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
872 - Depth Optimum 24.445.7 cm 604 555
Depth Tolerate 12.291.4 cm
Details
The optimal water depth for brown trout redd construction was 24.4-45.7 cm,
with a suitable range of 12.2-91.4 cm.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
873 Depth Prefer 31.7 cm 595 555
Details
Preferred brown trout spawning depth was 31.7 cm.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
874 Water Motion Optimum 53.368.6 cm/s 604 555
Water Motion Tolerate 15.291.4 cm/s
Details
The recommended optimal water velocity range is 53.3-68.6 cm/s. Suitable
ranges for spawning brown trout are 15.2-91.4 cm/s.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
875 Water Motion Prefer 39.4 cm/s 595 555
Details
The mean preferred brown trout velocity was 39.4 cm/s. Velocity was more
important than depth for selection criterion.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
876 Water Motion Tolerate 13.745.7 cm/s 592 555
Details
A velocity range of 13.7-45.7 cm/s for spawning brown trout has been listed.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
877 Water Motion Optimum 4070 cm/s 555 -
Water Motion Tolerate 1590 cm/s
Details
A velocity tolerance range of 15-90 cm/s (with an optimal range of 40-70 cm/s)
was assumed for this model.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
910 Southwestern Water Motion Limit 0.11 m/sec 608 555
Ontario
Details
The lowest identified brown trout spawning velocity was 0.35 ft/s.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
911 Washington State Water Motion Limit 1.16 m/s 575 555
Details
The highest identified brown trout spawning velocity was 3.8 ft/s.
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
912 Utah Water Motion Characteristic 0.46 m/s 569 555
608
607
Details 596
The mean identified brown trout spawning velocity was often 1.5 ft/s. 574
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
913 California Water Motion Prefer 0.2152.00 m/s 576 595 555
574
Details 575
Undefined preferred brown trout velocities were usually 0.7-1.7 ft/s range. 569
Ref. No. Locality (Stock) Factor(s) Influence(s) Data Primary Ref. No. Review No.
914 Depth Limit 0.060.24 m/s 555 -
Details
Minimum brown trout spawning depths were 0.2-0.8 ft.