Labor Day, 2008. From the safety and comfort of my Starkville home and through the convenience of the internet, I watched Hurricane Gustav smash into the Louisiana coast a few miles from where I had planned to be chasing redfish this holiday weekend. Reading the blogs on Gustav, I learned that hurricane soothsayers put a lot of emphasis on atmospheric pressure.

Of course, anglers put a lot of stock in atmospheric, or barometric, pressure, too. I've heard many anglers claim that fishing is better under low pressure, worse under high pressure.

No, I'm not recommending fishing in hurricanes. Remember The Perfect Storm?

But the repetitive reference to atmospheric pressure made me think about the effects - or supposed effects - of atmospheric pressure on fish. And that leads to the all-time greatest excuse for not catching fish - cold fronts.

I've caught fish after cold fronts, even had some great days. But I've not caught fish after cold fronts, too. I don't have any can't-miss strategies for catching fish after cold fronts, but I can share a little bit about water, pressure and fish that may help you form your own thoughts about cold fronts and their effects on catching fish.

Pressure effects

Except for infrequent events like hurricanes and tropical storms, barometric pressure usually ranges from about 990 millibars, or 29.2 inches of mercury, to 1030 millibars, or 30.4 inches of mercury.

Anyway you report it, the result is the same - a rather severe change in barometric pressure, one that occurs when the barometer changes from very low to very high, is only a change of about 4 percent.

Can fish detect this? Probably. Any fish with a swim bladder has a built-in pressure-detecting organ. And sharks, which lack swim bladders, have sensory cells that detect changes in water pressure.

Water is heavy stuff, and atmospheric pressure increases one atmosphere for every 10 meters - approximately 33 feet - increase in depth.

Doing the math, the 4-percent increase in pressure that a fish would experience with the passage of a major cold front equates to the same pressure change a fish would experience moving down in the water column about 16 inches. It's a pretty safe bet that the "discomfort factor," which I've read in more than one article, isn't what changes the fish's behavior.

Another way to look at this is that if the fish really wanted to experience a set atmospheric pressure, it would move up in the water column to adjust for the increased pressure following the cold front. Some anglers insist fishing deep is the way to go after a cold front. Might be, but if maintaining a constant pressure is important to the fish, they may have moved up in the water column from where they were before the front passed.

Temperature, sun, wind

Some anglers claim that it's not the pressure change but the weather conditions that usually accompany a cold front - cooler temperatures, bluebird sky, north wind.

The temperature change that we experience with a cold front, especially a winter or spring front, can be severe, maybe 30 degrees. But fish live underwater. Water will cool down when the temperature plummets, but not as much as people think.

Sure, your temperature gauge says the water cooled 3 or 4 degrees, maybe even 6 degrees. But that is surface water temperature. The strong wind that often accompanies a cold front will mix the water, so the cooling effect will occur deeper. But the more the water mixes, the less will be the cooling effect. If lake temperature responded as rapidly as some anglers think, we should have bass spawning after a warm week in February in Central Mississippi.

Bluebird skies mean more solar radiation and more UV light. The brighter light doesn't hold up, because light intensity changes from dawn to dusk every day, bluebird sky or not. There may be something to UV-light transmission. Although most UV light is filtered in the upper few feet of the water, a few studies have suggested that fish may use UV for feeding. If you buy into the UV-light idea, don't use that excuse on a cloudy, post-front day.

Do the fish care about wind? Those in shallow water on the windward shore may if 2- to 3-foot waves are crashing into their home, but it shouldn't affect other fish.

Wind can generate slight currents in the lake. These currents can, supposedly, concentrate plankton on the windward shore that, via the food chain, attracts the predators we are seeking.

In hydropower reservoirs, like Pickwick, flowing water turns on the bite. It's hard to conclude wind is a factor, except it makes fishing difficult, maybe even dangerous on some of Mississippi's larger reservoirs.

For two years while a graduate student, I measured food consumption of adult largemouth bass held individually in tanks. On any given day, five to 10 bass were swimming in tanks with bluegill forage. A day didn't go by that at least one bass didn't eat a bluegill. Do cold fronts affect fish? Maybe, but probably not as much as they affect anglers.