Majority of anglers can agree that there are many natural elements that come into play which affects fishing. These include air and water temperatures, winds, currents, water clarity and the level of light available. However, the one element that is most critical to understand and sometimes goes unrecognized by anglers is barometric pressure, also known as atmospheric or air pressure.
Most of us have experienced a day of fishing when the bite was nonstop action but then the next day we couldn’t buy a bite, despite fishing the same methods and 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 how 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 bladder 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.
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 clouds start to roll in and the poor weather is approaching. This is a great time to use fast moving baits and presentations. When trolling a large lake use fast trolled lures such as Bucktails or plugs because it will cater to the aggressive feeding fish. When fishing rivers retrieve large streamers or minnow patterns across a fast run, active trout will chase your down fly and hammer it. Fishing during falling barometric pressure is one of the best times you can fish!
During Low Pressure: 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 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 is 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 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 bottom in deep water could result in encouraging an opportunistic fish to strike.
Rising Pressure: Once the storm passes over the pressure will start to rise again bringing blue bird skies with no wind; but the fishing will continue to remain slow as the fish have to adapt to the pressure changes. Their feeding habits will take a day or two to return to normal. The colder the water temperature the longer it will take for the fish to adapt. One good thing about after a storm front has passed through is that it tends to wash a lot of food back into the water for the fish to feed upon. For example, when fishing a river a surge of rain can push a variety of terrestrial insects into the water. When the fish become active again there is plenty of food for them to forage on, so using terrestrial fly patterns during this time can be successful. During a rising pressure system and when fishing larger water bodies you may find the fish stacked up within the same zone in the water column. This is a good time to try to irritate them into striking your gear with some sort of lure that provides vibration. Using irritant scents such as garlic and anise can also aid in getting those stubborn fish to strike. Again, using slower trolled or retrieved lures is ideal in these conditions. Fishing near the surface on large water bodies is not a good option during this time.
Stable Pressure: Once the barometric pressure becomes stable fishing will convert to average again. This is a great time to try new fishing techniques as the fish have gone back to their normal feeding activities. This is when anglers will have to search for the fish using the other natural elements such as wind or current to help determine where the fish will be found.
Forecasting barometric pressure is a lot more difficult than forecasting the weather, however paying close attention to the weather trends mentioned above will lead you in the right direction. Using weather forecasts that predict the air pressure will aid you in planning your fishing adventure. No matter what the air is doing, any safe weather day is a good day to go fishing in my books!
This article was originally published in The Western Woods & Water Magazine. To see more excellent fishing articles like this one, subscribe to this online magazine for FREE by clicking this link!