Barometric Pressure and Carpin'

For many years now I have been collecting data that seems to link carp feeding activity to the ever changing weather systems that cross over the US on a daily basis. My main area of interest is the effect that the barometric pressure has on the daily routine of carp, in particular how it seems to control their feeding habits.

This interest first surfaced about 10 years ago, when for some inexplicable reason the carp suddenly stopped feeding after what had been a very hectic 2-3 hours. On my deck I have a little weather station which includes rainfall measurement, high and low temperature recording and a barometer.

I glanced at the barometer and noticed that in those couple of hours the pressure had dropped significantly and was now below 30 inches, whereas when I started it was above. The pressure continued to drop, and some hours later a thunderstorm rolled through.

This got me thinking back to a book I had read many years before called Fishing for Big Pike, written by Barrie Rickards and Ray Webb. In one chapter Ray Webb had discussed the impact barometric pressure had on the feeding habits of pike in his local water, and concluded that a sustained low pressure was a good time to try deadbait, but a high pressure would result in more pike to livebaits.

From my simplistic way of thinking I came to the conclusion that maybe, just maybe, the carp were effected in a similar way. Low pressure in the carps case signaling a reluctance to move around and feed as much as when a high pressure is in control of the weather.

So from that point on, I have kept an eye on the pressure at the start and end of my fishing session. For the last couple of years I have been viewing the Intellicast web page, which has an excellent previous 48hrs observation page. Here it gives the pressure readings hourly.

I can check the trend, which in some cases is more important than the actual numbers. Referring back to Ray Webb's conclusions, the best time he found was after a sustained low pressure when the pressure started to rise rapidly. I have found the same to be true for carp.

I can't wait to get out fishing when I check the 48hrs page and see the pressure is rising by the hour. I have never failed to catch carp in this scenario.

So why do carp, or any other fish, notice any change in atmospheric pressure. After all, we all know that water is uncompressable, so why and how does it effect a carp.

All their lives are spent traversing the depths and shallows of a lake where their bodies must experience quite dramatic changes in water pressure. It seems strange that a small change in atmospheric pressure would have such a big impact on them, but without doubt it does, and although I have yet to draw any reasons for this, I know for a fact that I have a tremendous amount of success when a high pressure system is in control of the weather.

My 'magic' number is 30 inches. Take my last 31 trips for instance. I have taken 218 carp, of which 187 were taken during the period of a high pressure system. The pressure during these 31 trips was:- 18 high and 13 low pressure.

In the 13 low pressure sessions I had 8 blanks and 37 fish. 21 of these were taken float fishing just off my boat launch on a tranquil August morning with a pressure reading of 29.97 to 29.95 in 2hrs. None were over 3lb. A really odd day, and one I have never experienced before or after.

The rest of the fish were all taken during high pressure systems and I had one blank in the 18 sessions. All of my 20lb+ fish came during high pressure too.

I don't need much convincing that pressure does have an effect on the carps feeding habits (in my lake) with numbers like that. I hope this may be of interest to you the reader. It certainly helps me decide when I need to take a 4 or 12 pack with me to the bankside :)

Pete Diffy