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Rod. Flies. Thermometer?

Rod. Reel. Line. Flies. Net. And… thermometer?

Even though they are ubiquitous in fly fishing catalogs and on gadget racks in fly shops, it is a good assumption that not everyone knows what they’re for. That said, so much has been made of the conscientious step of being mindful of water temps in the summer when fishing for trout. More and more anglers are aware that a small tool can do a lot more than barbless hooks to cut down on seasonal fish mortality.

All that said, there is more that you can do with a thermometer. In fact, it can help you find and catch fish. How is that?

Today I’m sharing three ways that a thermometer on the stream can help you  figure out if a spot  where you should fish or not?

Is it right to fish?

This is the most common reason people carry thermometers while fishing. Is it ethical to take fish, especially species like trout, when the water temperature is above X degrees? Having a way to obtain objective data and make an on-stream decision is quite handy and, more importantly, responsible.

But again, a thermometer can do more than that. You can key in on thresholds for insect activity, for trout behavior, and a number of other temperature-related environmental factors. But you can also figure out if  this where I should fish?

How can a thermometer help you figure out if a spot is worth focusing on or not? Here are three ways:

Is it stagnant backwater or a fishable eddy?

Slow, churning pools are hard to pass up. They also create challenges for presentation, as their currents often run the opposite direction from the main current. Consequently, you might spend a lot of energy and effort getting good drifts in these spots. Coming up fishless is then that much more discouraging. Sometimes it has nothing to do with you. Sometimes, the water might be stagnant and not ideal holding water. A quick check of the temperature will let you know if it is the kind of place trout will seek out or avoid at all costs.

Is there a spring?

Spring seeps keep fish alive in abnormally hot summer stretches. At these times, you can identify their location because trout will be crowded into a seemingly random spot in the creek. When this happens, it is best to pass on and leave them be. But if you’re wading in more reasonable weather and the water feels cooler, getting a reading and tracing  this water to its source can pay off. Finding a spring seep is a treasure for winter angling, and is valuable information the rest of the year.

Is the tributary  influencing the water temp?

Unique circumstances present for angling opportunities when two waters meet. The influx of colder or warmer water provides something special for plants, bugs, and fish. But no two tributaries do the exact same thing to the river into which they flow. It takes a little legwork, but sampling water temperatures at various points around the confluence can give you an idea of what is going on. And, as always, knowing what is going on will lead to better informed positioning and presentations.


Have more uses for a thermometer while on the water? Let me know in the comments below.

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