Smallmouth and River Temps, How Warm is Too Warm?

[troutbert]

For many decades I've read for trout the water temperature at which you should quit fishing is about 70F.

But I've never heard anyone state a similar number for smallmouth bass.

Any thoughts on this?

I once took a temp of 90F in the Susquehanna River. So waters that hold smallmouth can get very warm.

 

[ratgunner]

Bass like it hot. Not sure how hot is too hot though.

 

[AFISHN]

I'm not sure about the "quit fishing" temp for SM.
I do know that one summer about 10 years ago, I was fishing the Susquehanna above Dauphin and the water was very warm.Caught a bunch of fish where there was turbulent/moving water over and around rocksbviously richly O2'd.

I was very careful not to play them too long and about the way I handled them,and especially to see if they needed reviving.None did .

Having said this,I would like to see some hard research on this subject

 

[Wildbrowntrout]

Lots of places I've looked say around 80 is getting to be too hot to fish them. I guess as long as the water is oxygenated, you should be alright above 80. Just like AFISHN said, try to get them off the hook quick and take the time to revive them.

 

[Dave_W]

The myth that river smallies are "coolwater" fish is a persistent one.

Bass love warm water and are happy in water temps of 80 degrees. In my experience once temps get up around 88 or 89 however, larger river SMBs seem to turn off and it is usually better to wait till dusk or early morning on those days (which are common). Not sure I think there is an upper temp limit for safe bassin but I'd be careful to release fish into oxygenated water if the temps are very high.

However, warm muggy days with river temps in the low to mid 80s often fish very well for bass.

(Muskies, however, are sensitive to heat and I'd suggest laying off them during summer heat waves.)

 

[Sylvaneous]

How warm do you think the James in Richmond gets? Or the smallmouth rivers in Missouri or North Carolina and Tennessee? Pretty freakishly hot, I'd bet. Nothing we have in PA will compare with a summer on the Piedmont. I lived near Fairfax VA for 5 years. That place got nearly as hot as the Philippines. And Richmond down to South Carolina was even hotter. That part of the world frequently gets hotter than Sarasota, Fla, where my other sister lives...just for comparison. They'll lay low in the hottest of it, but I bet fishing at night would be gang-busters. Their metabolism would be through the roof! Feed. grow. Feed. Grow....

Syl

 

[Mike]

You will most likely find your answer by searching for the smallmouth bass Habitat Suitability Index.

 

[afishinado]

Adult bass in the laboratory preferred
temperatures of 28° C (Ferguson 1958; Bennett 1965) to 31° C

(^That 's 82-88* in Fahrenheit)

Link to Source: Habitat Suitability Information: Smallmouth Bass

Temperatures may be the most important single factor limiting distribution
of smallmouth bass (Robbins and MacCrimmon 1974; Coutant 1975). Faster
growth rates of adult smallmouth bass are generally associated with higher
summer temperatures (Ooan 1940; Brown 1961; Forney 1972). Faster growth rates
occur in southern reservoi r s , resul t i ng . tn earl i er death than in northern
regions (Coutant 1975). In the summer, bass inhabit warmer shoreline areas of
large lakes in the North and deeper, cooler waters in the South (Coutant
1975). Growth does not begin until water .temperatures reach 10-14° C (Coble
1975). Field data indicate that adults prefer temperatures of about 21-27° C in the summer (Clancey 1980). Smallmouth bass have been reported "sunn l nq"
themselves in pools with water temperatures of about 26.7° C in summer (Munther
1970).
Temperature preferences of smallmouth bass vary considerably depending on
the acclimation temperature (Ferguson 1958; Cherry et al. 1975; Coutant 1975).
Smallmouth bass acclimated at 2.2-30.0° C selected temperatures of 20-32° C in
laboratory tests (Mathur et al. 1981). Adult bass in the laboratory preferred
temperatures of 28° C (Ferguson 1958; Bennett 1965) to 31° C (Barans and Tubb
1973; Coutant 1975). Optimum growth rates in the lab occurred at temperatures
from 26-29° C (Peek 1965; Shuter et al. 1980; Wrenn 1980). Upper lethal
temperatures for adults were above 32.3° C (Coble 1975).
When temperatures drop to 15-20° C, adults seek deep, dark areas (Webster
1954; Munther 1970). At about 10° C, bass become inactive and seek shelter
(Coble 1975; Shuter et al. 1980). At 6-7° C, most smallmouth bass are beneath
the rock substrate, with few remaining on top (Munther 1970). The lower
lethal temperature is near freezing (Coble 1975).

 

[afishinado]

Here's an interesting summary of a SMB study I found:

We monitored the movement and habitat use of 34 stream-dwelling smallmouth bass Micropterus dolomieui in Jacks Fork River, Missouri, by radiotelemetry. Observations were made 24 h/d in all seasons. Definite patterns of diel activity and habitat use were evident and were modified by seasonal changes in water temperature. Fish remained in restricted home ranges for most of the year but tended to disperse in spring when all of the radio-tagged fish left their home pool; 75% returned during the same season. Equal numbers of fish moved upstream and downstream. However, the median distance moved upstream was greater. Intrapool movement of smallmouth bass peaked soon after sunrise and again after sunset in all seasons. Average intrapool movement was 120 m/d when water temperatures were lowest (4°C) and 980 m/d when temperatures were highest (27.5°C). In the warmer seasons, fish preferred logjams and root wads by day and increased their use of boulders at night. In cooler seasons, fish used boulders almost exclusively. Regardless of season, open water without cover was used most during the period just after sunrise but was never used in proportion to its availability. Boulders were the most preferred substrate, and gravel was the least preferred. Small mouth bass used intermediate depths the most and showed no daily or seasonal changes in depth preferences. Fish preferred velocities less than 0.2 m/s at all times of day and in all seasons. Movements in floods did not differ from those observed during normal discharges; however, single logs were selected in significantly greater proportion than logjams.


SMB Study

 

[troutbert]

For those who want to convert C temps to F:

Multiply by 1.8, and add 32.

IMHO anyone publishing research papers in the US should include both metric and "American" measurements.