Different species of fish prefer different water temperatures. The fish you have access to in your local stream or river will depend on the temperature and cover – and even though many warmwater fish can survive over a wider range of temperatures than coldwater fish, there are still ideal conditions for the species you are hunting.
How can I quickly & accurately test water temps?
Testing the water temperature when you’re fishing is a good idea in general, and one of the tools that I usually take with me is a Deeper Pro+ Sonar. There are multiple models available at different price points.
The added benefit is that you can tie this unit to your fishing line and cast it to inspect the opposite shoreline, deep holes or underwater structure. (Personally, I use mine to create useful topographic maps when I am fishing from the jon boat, and occasionally when fishing from shore. The maps are great for reviewing after I get back from a trip to learn even more about the area.)
Preference by Species
Most anglers know that trout need cold water, and largemouth bass prefer warmer water, but what they don’t realize is that there are considerable differences in preference even among warmwater fish. The chart below shows the preferred temperature ranges of common warmwater species – notice that the range covered is more than 30 degrees.
Even though many warmwater fish CAN survive over a wider range of of temperatures than coldwater fish, there is still an ideal temperature range required for every species to thrive. For example, a warmwater fish could survive in a trout stream, but the water temps would be too low for optimal feeding and growth, making it difficult to compete with the trout or grow to the size we’d like to catch.
The temperature of a stream depends mainly on it’s primary source of water. To support a diverse population of fish, additional springflow is usually necessary. Springflow helps the water stay cooler in the summer, and warmer in the winter (preventing freezing, and allowing fish to feed throughout winter instead of going dormant).
Other factors like shade, the course of the stream, the shape of the channel and the gradient of the streambed all impact the temperature as well. Different sections of the same stream can be different temperatures. For example, a shaded stream can run 5 to 10 degrees cooler than a similar stream in direct sunlight. A shaded run can also be several degrees cooler than an unshaded run in the same stream.
Water in narrow, deep channels tends to stay cooler than water in wide, shallow channels because less of the water comes into contact with the air.
Some streams or rivers also contain lakes along their course. Some are natural, others are the result of a dam. In either case, the stream temperature below a lake will be several degrees warmer than the stream temperature above the lake (unless the lake has a coldwater draw, which we will talk about in the next section in this series). The lake water may also stratify into different layers, however this does not happen in streams or rivers – the water stays turbulent and completely mixed – which means the surface temperature is darn close to the temperature right above the streambed (unless the water is very deep).
Water Temperature by Species Chart
Information provided courtesy of: The Freshwater Angler™: Fishing Rivers & Streams.
|Redbreast Sunfish||80° to 84° Fahrenheit|
|Flathead Catfish||78° to 82° Fahrenheit|
|Blue Catfish||77° to 82° Fahrenheit|
|Channel Catfish||75° to 80° Fahrenheit|
|Bluegill||75° to 80° Fahrenheit|
|Spotted Bass||73° to 77° Fahrenheit|
|Redear Sunfish||73° to 77° Fahrenheit|
|Black & White Crappies||70° to 75° Fahrenheit|
|Largemouth Bass||68° to 78° Fahrenheit|
|Muskie||67° to 72° Fahrenheit|
|Smallmouth Bass||67° to 71° Fahrenheit|
|Striped Bass||65° to 75° Fahrenheit|
|White Bass||65° to 75° Fahrenheit|
|Walleye||65° to 75° Fahrenheit|
|Northern Pike (under 7 lbs)||65° to 70° Fahrenheit|
|Northern Pike (over 7 lbs)||50° to 55° Fahrenheit|
|White Sturgeon||65° to 70° Fahrenheit|
|Wiper||64° to 66° Fahrenheit|
|Sauger||62° to 72° Fahrenheit|
|Shad||60° to 65° Fahrenheit|
Now that we know what species typically prefer what water temperatures, we’re going to look into some other factors that can impact the overall temperature of a stream or river. This is yet another piece of the puzzle that we are putting together to get ready for some new exploration this coming year.
Onward my friends – tight lines!
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