Thread: Barometric pressure

I watched the pressure all day this weekend. Crazy how a slight drop or uptick changes things. I'm a believer for sure.

Here are some science facts you might be able to apply concerning barometric pressure and fish behavior:

A. The volume of a gas varies directly with temperature and inversely with pressure. A sudden drop in pressure results in an increase in gas volume and an increase causes the gas to expand.

B. The gas in a fish's swim bladder is pure oxygen. Too add or remove gas from their swim bladder is done by taking it from or giving it to their blood stream. (No they don't expel gas like we do !!) This process takes considerable time..... days not hours.

C. Fish are lazy, they want to save their energy for basic survival, and therefore will suspend at a depth where they have neutral buoyancy rather than having to continually swim up or down to retain a certain depth.

D. Changes in pressure have an immediate effect, but water temperature changes are slower in most cases so fish have more time to adjust to temperature so behavioral changes are also slower.

So..... when the barometer drops, the fish will start adding oxygen from its swim bladder into the bloodstream. These higher oxygen levels will give it increased energy causing increased activity (often devoted to searching for prey). Dropping pressure will also immediately cause the fish to move shallower to be at a depth providing neutral buoyancy until the longer term bladder volume changes all a return to their preferred depth (usually where food or shelter is available).

When the pressure increases, they go deeper to suspend and begin to slowly add oxygen from their blood to their bladder to be able to return to their preferred depth. Lower oxygen levels in their blood results in lethargy and inactivity.

Bottom line is go fishing anyway! Just remember that when pressure is falling like before a front bite is likely to be shallower and better than the day before, and when higher fish are deeper and bite will be slower. Watching the barometer can give you some idea what the fish may be doing, but it is not the only change that affects the bite.

Good reading.

Well , the theory worked today , culled out a limit anyway.

I never got a bite. There was 6 other boats there with no fish when I was there. 98 bridge Conway

Well I didn't get skunked but only 1 crappie and 4 whites for us down on Little River, other boats were saying same thing, fish were biting back before Christmas but not now. I hit a lotta tops up and down from White Cliffs Rec. area from nearly to Jacks Isle up to about Brown Slough. Fished til the rain ran us off around 2pm.

High Pressure means deep water....thats where you will find em bitting.

Cache 22
I always have to know "why". You have explained it. But, I ain't never going to remember all of that stuff.
DP