What is Barometric Pressure?
Barometric pressure, or atmospheric pressure, is the pressure applied by the weight of air in the atmosphere. Typically, when a storm is forming, air density lessens, causing lower barometric pressure. The barometric pressure will rise after the storm has passed and the sky starts to clear. It is imperative for any serious fisherman to pay close attention to the barometric pressure prior to fishing because, as you’ll read below, it can affect what lures you choose to tie on.
Breaking Down Barometric Pressure Fishing and Its Effects on Bass
Without getting too scientific, let’s discuss why fluctuations in barometric pressure affect bass activity, and thus the success of using a topwater lure. Imagine air density as a more solid structure, a drywall ceiling for example. You are lying on your back on the floor of a room, facing up to a standard 9-foot ceiling. This current environment allows plenty of room for you to move, without any restrictions. We’ll refer to this as the normal, low pressure level, like the comfortable environment a bass is in during normal barometric pressure levels. Now imagine, in that same room, the ceiling begins to move closer to the ground, closing the gap between you and the ceiling causing limitations in your ability to move in the space. This situation would be similar to high barometric pressure levels in the atmosphere, with dense air pushing down on water, limiting the ability for bass to move freely in the space.
When the barometric pressure is high or rising quickly, bass become very uncomfortable and seek to avoid the areas more susceptible to high pressure such as shallow sections of water. Bass have air bladders, so in higher barometric pressure environments their bladders fill up with more air while in shallow water, increasing discomfort. Basically, when in shallow water, the bass get bloated!
In these high pressure conditions, you’ll find bass either in deeper areas of water where they can gain more space between themselves and the top of the water column, remaining active and neutralizing their bladders, or you’ll find them relatively inactive in the beds of the shallow sections. So, it only makes sense that in these conditions, topwater lures are less successful, because the bass have moved from shallow water areas or are relatively stagnant in shallow water.
Barometric Pressure and Productive Topwater Fishing Go Hand In Hand
I recently had a series of fishing trips that emphasized the importance of reviewing barometric pressure readings prior to fishing. In early August, I fished a tournament on the Ohio River in West Virginia. On tournament day, without considering of the atmospheric pressure levels, I chose to start off with Whopper Plopper due to the low light and partly cloudy conditions. I managed to have a decent run that day, satisfied with my technique and the outcome.
Three days later, I fished the same general location, still not paying attention to barometric pressure, and was unsuccessful with topwater lures which seemed strange as the water temperature was the same as three days prior when I had caught plenty of fish. Several days later, I again met with the same result, managing to only catch a few punching grass mats, but not even a sniff at my topwater lures. When I got home, I looked at my ANGLR data I gathered while using my Bullseye, see if I could find any explanation as to why I was able to catch bass tournament day with topwater lures, but then had no activity the following trips using the same technique in the same area.
I discovered a correlation between bass topwater activity, or lack thereof, and the daily barometric pressure readings. The images below, captured from the ANGLR web app, prove that bass will shut down on biting topwater lures, even in the slightest increases in atmospheric pressure.
During the tournament, the barometric pressure reading was 1351.51mbar.
On the second trip, the reading was 1351.92mbar. Only a slight rise, but after looking with more detail, the second trip was right as the pressure began to rise after a passing front.
The third trip really seemed to confirm this trend for me. At 1354.41mbar, I didn’t see any topwater movement, not even baitfish, let alone get a bass to consider following my topwater lure.
This data helps me gather my base measure of mbar for deciding when to switch from, or to, topwater lures. As I fish the area more frequently and gain additional pressure readings along with analysis of bass activity, I can refine this baseline even more. Remember, the normal or ideal barometric pressure level for an area is unique to its location, factors such as sea level and geographic region impact the “normal” pressure for a location. Information regarding specific barometric pressure levels can be found online, but I chose the ANGLR Bullseye so I could track live weather and water conditions in my area while fishing. Reviewing this data prior to going out on the water is helpful, allowing a fisherman to determine what lures to begin with in low or high-pressure conditions.
How to Target Fish During High Barometric Pressure Days
I know what you’re thinking, how do I catch these bass when my topwater bite dies off?
I would seek out ledges, deep pockets or holes with shallow water close by, casting a drop shot, shaky head, Texas rig, or Carolina rig. Really, any bait that will allow for a slower presentation, let the fish tell you how fast or slow to move the bait. On incredibly high-pressure days, they may be incredibly fickle, so testing retrieval speeds is key. I like to stay near shallow water, even in fluctuating pressure levels, because bass will still swim up to the shallows to feed when the barometric pressure starts to drop. In early spring and late fall, I focus on main lake or river points with deep water close by, mixing in deep diving jerkbaits and crankbaits in a shad color; replicating their food source is always a good way to get them to eat.
Whether you decide to start shallow or deep, consider the atmospheric pressure levels if you feel the need to change your technique to match bass activity. The image below is from a tournament in my home state of Michigan this past spring. On this high-pressure day, I chose to start shallow and ended up fishing for an hour with no bites. I made the decision to switch it up, moving to a ledge and casting a drop shot.
Forty-five minutes later, we had our limit.