How Does Barometric Pressure Affect Fishing?


What is Barometric Pressure and why does it affect fishing?

All anglers know that the barometric pressure has an effect on fishing.
How the pressure directly effects the fish may still not be an exact science, but some understanding of how to use the barometric pressure readings along with other natural influences is a part of the puzzle to increase your chances of turning fishing into catching.

Question: How many days does it take for fish feeding to stabilize after the passage of a front?
Answer: After three days of constant weather pressure the fish will start to become accustom to the conditions and return to normal activity.

What is barometric pressure?

Barometric pressure, also known as atmospheric pressure or air pressure is defined as the force exerted by the weight of the atmosphere pushing down on a given area.
It is instrumental in weather observations, since its fluctuation indicates the movement of weather fronts and systems.
Liquid mercury (Hg) is commonly used in barometers to measure air-pressure changes in inches (in.)

A barometer reading of 30 inches (Hg) is considered normal.
Strong high pressure could register as high as 30.70 inches, whereas low pressure associated with a hurricane can be below 27.30 inches

But it's not so much the actual number reading as the trend the readings are taking.
A steadily falling barometer usually signals a storm is approaching, while a rising barometer normally means clearing weather.
A very low reading (under 29.50 inches) can suggest a strong storm approaching.
Conversely, high atmospheric pressure usually arrives after the passage of stormy weather.
When high pressure settles over an area, it often means blue bird days and calm winds.

How does barometric pressure affect fish?

A fish senses pressure changes through its air bladder.
Fish that have small air bladders don't seem to be as affected by barometric changes as those with large bladders. But remember, forage fish they feed on have air bladders, and that alone could have a big impact on where you might find fish and how they behave.

Fish with large bladders quickly sense when the air pressure is dropping, because there's less pressure on their bladder.
And when there's less pressure squeezing their bladders, the bladders expand a bit.
When their bladders expand, fish become uncomfortable.
They relieve their discomfort by moving deeper or by absorbing extra gas in their bladders.

Does Low Pressure mean slow Fishing?

Fish are much more comfortable when there's stable high pressure, and will tend to feed actively most anywhere within the water column. Also with passing of several cold fronts in quick succession with cycles of high and low pressure definitely changes how fish react to pressure changes.

The fish can sense that the pressure is dropping in front of storm system. So, as the high pressure begins to dissipate, the fish respond with a change in feeding patterns. Fish often feed heavily right before the pressure drops. When the front passes and high pressure moves back in, the fish may not feed aggressively for at least 24 hours, since they're still adjusting.

"However, it's a different story a day or two after a high settles back in. The fish will have had time to stabilize and an intense bite can occur. When the pressure changes again, such as when another front moves in, the cycle repeats itself."

Baitfish are also affected by barometric pressure. For example, falling pressure may force the bait to hold deeper and become less active, which would impact the fishing in the middle and upper levels of the water column.

Along with Barometer Pressure
Other natural and some unnatural influences on fish behavior.

  • Temperature of water and / or air.
  • Clarity of water.
  • Changes in water levels.
  • Flooding of new ground.
  • Time of year
  • Time of day.
  • Light Penetration
  • Depth and type of the body of water you are fishing, lake, pond, river, bayou etc.
  • Species of fish your after.
  • Structure or lack of - depends on species of fish.
  • Moon phase.
  • Amount of / or lack of forage in area your fishing and what type of forage.
  • Current.
  • Dissolved Oxygen levels.
  • Wind Speed and direction.
  • Natural Noise as in Heavy Thunder over the water your about to fish ( I hope your not on the water in lighting).
  • Noise as in manmade.

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c 9-2019


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