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The Shotem' and Caughtem' Blog is the place to find the latest reviews and commentary on gear, destinations, conditions, events, and general knowledge to inform our readers and give our opinions to anyone listening.

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Monday, 28 April 2014 22:09

Barometric pressure and fishing

Thunderstorm fishing Thunderstorm fishing

We at Shotem and Caughtem have always been told the stories and ran to the lake to answer the prophecy that the best fishing happens before the storm.  So of course now that much of the United States have been involved in a large line of thunder storms we felt it might be good to look at the science behind fishing and storms.  

Barometric pressure- the weight of the air- decreases as a storm approaches. It's called low pressure. To understand how it works, imagine the palm of that giant hand the professor talked about easing up as it presses on the water's surface. Its touch is lighter. The water isn't as compressed as it was, and fish can move more easily through it. The mood of many fish often changes to what we might call a more 'active' mood. They move around more freely and feed.

A storm also brings clouds and wave-creating wind, reducing sunlight penetration. Active fish can move to shallower water. In the case of walleyes, they often rise in the water column. The sonar screen shows them moving up off the bottom. Or, they just move shallower on shoreline-connected and midlake structures.

The absolute best fishing periods often occur when barometric pressure reaches its lowest point, just before the front arrives.

"The old saying, that fish bite best right before the storm."

The best time to head to the lake is when the forecast calls for storms moving into the area.

The picture changes when the storm is over. Barometric pressure starts to rise again. The giant hand presses down harder, and the water becomes more compact. High pressure also brings clear, bluebird skies, and light penetration is often intense for the next several days. Fish feel the increased pressure and become less active. They move tight to cover or deeper, where the sun isn't so bright. Their mood is lethargic.

With underwater cameras, you can watch fish come up to a bait and not bite. People don't understand that, but when air pressure is high, fish become less aggressive. They just come up and look. They may eventually take it, but you have to work a little harder.

The effect of the pressure change is most pronounced on the first day after the storm passes.

Time of year must also be considered. The impact of a change in barometric pressure is more severe in winter. For one reason, the swing between high and low pressure is more drastic during the cold months. For another, the same high pressure is affecting less water volume when part of it is locked up as ice.

Fish like northern pike may be the least susceptible to changes in barometric pressure; they seem to be aggressive no matter what. But, the perch family, including walleye, may be the most impacted by the changes, followed by crappies and bluegills. Heitkamp doesn't target muskies often, but anyone who does will tell you the best time to be on the water is when black clouds appear on the horizon.

A barometer isn't needed to know what's happening with air pressure. Read the wind instead.

Anyone can play amateur weather forecaster. Before the (storm) front, wind is out of the south. When it switches to west-northwest, pressure begins to rise.

"Wind from the east, fish bite the least." 

Wind comes from the east the longer high pressure is in place. By then, high pressure has taken a real toll on the fish.

Let us know your weather tricks and tips in the comment section below.