How Barometric Pressure Affects Trout and Salmon

By Danny Coyne

How barometric pressure affects fishing fish with large swim bladders, such as trout and salmon, are more sensitive to pressure changes. 

The majority of anglers can agree that there are many natural elements that come into play, which affects fishing. These include air and water temperature, winds, currents water clarity, and the level of light available.

Most of us have experienced a day of fishing when the bite was non-stop action, but then the next day we couldn’t buy a bite, despite fishing the same methods in the same areas. This extreme flip in fishing action most likely occurred due to changes in the barometric pressure.

Simply put, barometric pressure is the weight of the atmosphere pressing down on everything on earth and it constantly changes from high to low.

When observing pressure for fishing, how high or low isn’t as important as which direction the pressure is moving and what speed it is changing.

Fish can feel the weight of the air pressing on the water by sensing the pressure changes in the air of their organs, especially their swim bladders, which controls their buoyancy.

Fish with large swim bladders, such as trout and salmon, are even more sensitive to these pressure changes.

So how does all of this affect fishing?

To make it simple, let’s break it down to a few periods on how you can use a barometer as a gauge on how the fish will be acting and feeding.

Affects of Falling Barometric Pressure

Fish can sense an oncoming storm as much as a day in advance. This is when the fish react and become very aggressive because they understand that feeding during the low-pressure storm periods can be a challenge. You can recognize the barometer dropping because this is when the clouds start to roll in and the poor weather is approaching.

Fish with large swim bladders, such as trout and salmon, are even more sensitive to these pressure changes.

This is a great time to use fast-moving baits and presentations. When trolling a large lake, use fast-trolled lures, such as Sling Blades™ and Rock Dancers® because they will cater to the aggressive feeding fish.

When fishing rivers, retrieve large streamers or minnow patterns across a fast run, active trout chase down your fly and hammer it.

Fishing during barometric pressure is one of the best times you can fish!

Effects of Low Pressure Weather Systems

Lucky for us anglers, low-pressure systems don’t tend to last that long. However, once the falling pressure has stabilized to a low-pressure system, the fish are going to retreat to the deeper water. One of the reasons they are doing this is to equalize their swim bladders.

The fishing will slow down as there is a lack of interest for the fish to feed — simply put, because they are uncomfortable. The shallower the fish are in the water, the more they will feel the results of the low-pressure system.

Effective fishing techniques during this time are to use slower-finesse presentations in deep water.

When trolling your gear, slow down and downsize your lures. The fish will not want to use a lot of energy to chase your bait.

When fishing rivers, try a nymph pattern drifted just off the bottom in slack water at the tail end of a run.

In smaller mountain lakes, using small flies, like chironomids or blood worms, suspended just off the bottom in deep water could result in encouraging an opportunistic fish to strike.