I apply it to fishing, but am more interested in how it is seen (or not seen) to effect daily patterns from those who raise them.
IMO, as it applies to angling,........................other conditions play a larger role.
I do think it plays a role. There are certain weather-related situations (fronts moving in, or stable weather pattern over a series of several days), that seem to trigger bluegills into feeding more readily. Now, it could indeed be that these same weather patterns are stimulating some sort of extra activity in aquatic organism that bluegills feed on. But sometimes the bluegills just seem to get real aggressive, even in the absence of signs of "hatches", or aquatic activity.
As you mentioned, it may indeed be a minor player compared to other factors such as water temperature, water clarity, and other such things that make up a fish's environment. In the grand scheme...I would say the importance of barometric pressure seems to fall somewhere between wind direction and moon phase (both of which I also consider to be minor, but measurable, contributors to a bluegill's behavior). ;o)
I'm hopelessly stuck on the learning curve with this topic. It's only due to the blantant fact that I tend to split hairs about cause and effect.
This is only opinion, so don't read it as fact - I don't believe barometric pressure has the direct effect on bluegills that most commercial literature claims. I think the cause is more directly related to the lower food chain, with the actions of fish (bluegill in this case) being the effect.
These are the facts (as I see them) that I'm basing this opinion off of: 1) Barometeric pressure and absolute pressure are directly related 2) The smaller the organism, the more effect pressure change has on it. While this statement can be applied to a large case set, I tend to look at a much smaller window: small fish seem to alter their lives faster and more drastic then larger fish of the same species (bluegill). Now, what needs to be kept in mind is where these different fish are living. You have smaller (younger) fish living in shallow(er) water then more mature fish. Shallow water will be more effected by pressure changes then deep water is. Put another way - what is a pressure change in shallow water may very be standard, everyday pressure in deeper water; hence no change regardless of a changing barometer.(atmospheric pressure change not to the extent to overcome the pressure of a given water column) 3) The journals I keep of personal angling trips do not share a common bond with the barometric readings - no matter how drastic they are. (Quite a few examples of this that I'll keep out of the discussion unless it leads somewhere) 4) Bluegill will make adjustments to their daily schedules regardless of the barometric movement or level. Current is the most prevelant example I can think of that shows this, be it naturally induced (wind), or manually introduced (dam gates opening or closing).
Not certain I'll ever fully understand this condition, but there's enough interest there to keep me coming back for more abuse.
I think that barometric pressure is signficant primarily in it's relationship to other weather events that are occurring simultaneously. i.e. cold front or warm front comes through with change in pressure also means other changes.
I think that the following factors that I can be more certain of their effect on fishing.
1. Light levels. Sudden increases and decreases in light, in the way of cloud cover have a significant effect on fish patterns and feeding. So many fish rely on sight advantages over prey, that a sudden change in light often triggers feeding activity, just like dawn and dusk.
2. UV. Ultraviolet rays have a clear identifiable effect on fish location in the water column. Weather patterns that create change in barometric pressure also effect UV. Low atmospheric humidity after the passage of a cold front means LOTS of UV penetration, and the associated changes in fish location due to UV sensitivity. Some fish simply won't stay shallow if there is lots of UV penetration.
3. Wind. Once again, wind changes can be tied directly to passage of a weather front. Wind affects like levels significantly, and it also lifts nutrients and small organisms, both plant and animal off the bottom, which triggers the sequence of events often referred to as the food chan.
I think all of these factors are so intertwined that it would be futile to try to say something as simple as "The barometric pressure changed, so my fishing success changed". Possibly too many things changing right along with it to ever be able to make the direct correlation.
Zig, I might not be understanding your point #2... Water isn't a compressible liquid, so atmospheric pressure would affect the entire water column the same...wouldn't it? Ow...I think I hurt my head.... ;o)
Ever have those "humid days" that just wanna make you go fishing? The air just SMELLS like good fishing?? Now I can't remember if those actually turned out to be good fishing days or not, but all days spent fishing are good in some fashion.
the most important thing that happens with a barometric pressure drop,is what it does to the bottom of the food chain.
This can push algae, and other micro organisms into the water column,which starts the food chain feeding cycle
from what i have read this effects shallow water fish more then deep water fish,including the mighty Gills and Chinks.
I go fish whatever I can! I noticed that few days around the Full and New Moon is good for fishing.
From Spring to Fall, fish deeper water close to shore where strong wind blow to shore bring lot of small baitfish and zooplankton closer to shore.
My favorite time for early spring is 3 straight 70's degrees day in a row and the third day in early afternoon is hot fishing for big bass and panfish in small lakes! I marked high temperture per day and if its 3rd day then I call sick day from work. Ha! Ha!
I don't even think of barometric pressure and I go fishing whatever I can!
Weather change then I go fish!
No offense, guys and gals, but I think all this barometric pressure stuff is just a bunch o' hooey! What I see making a difference, like some others have mentioned, is UV penetration, sunlight levels, and wind/wave action. Now, don't get me wrong: a sudden change in barometric pressure is usually caused by a major front, which either gives you clear skies and major UV penetration, or serious cloud cover and less UV (although not MUCH less, as you can get a sunburn on a cloudy day almost as easily as clear). The fish do seem to appreciate stable wx conditions, whether constantly good or consistently bad. Give a front 2 to 3 days to get away from your area and it seems the fish are back in business. If the front stalls over you, go annoy someone on the internet 'til it's gone. :-D Of course, YMMV.