Catching fish or going fishing to your favorite spot is like, well, turning on a light switch; up it is on, down it is off. Fishing pressure, traffic, weather and water conditions can all cause bite-on to bite-off behavior, causing a previous productive fishing pattern to fall apart. Change is not a bad thing if you can read the pattern and understand just what is going on with that area of concern under the surface in that mysterious realm beneath the waves. Like that of a light switch, your hotly tot hole may be a turn on today but tomorrow in is a true turn off dead spot; in a word of why, pressure. Understanding the fish behavior puzzle is to understand the links to fish and the barometer or pressure reader. When in the water any object, including the fish, either sinks, floats to the surface or suspends and even the smallest of change in barometric pressure is to a degree like a change in gravity; because objects weigh less in the water, the affect of a pressure change is far more pronounced beneath the surface than above.
Fish are more in tune to the environment more than we humans are. Fish have an incredible array of pressure-sensing systems; such as the lateral line, which keys them in to changes in barometric pressure and, in turn, signals feeding opportunities or foretells the arrival of major weather changes, in the form of pressure gradients, which then determine on when the “Bite” is either on or off. A drop in pressure, a cold front, can cause tiny particles of sediment as well as zooplankton and phytoplankton’s to float off bottom, rising higher in the water column than they normally suspend which, in turn again creates a reduction in water clarity and usually a bite happens as Glass minnows to Mullet frenzy into a feed. As these species, show movement into that of a theatrical moment so does the feed habits of the predators around them causing all to “Bite On!”
Pressure changes occur on the passage of any front or pressure gradient. It does not have to be a cold front to trigger a bite before; many a time on the water, I have used the forming of a cloud moving towards the boat to switch up to an aggressive angling pattern. As this cloud grows darker and spitting drops from aloft fall, so too does the surrounding pressure under the cloud. Usually the fish will “turn on” but for a moment as it passes by. Be alert to the lightning to move towards safety but work the clouds in the summer much as you would a pattern of diving birds. The key to great fishing is coming up with a good game plan based on forage, structure, seasonal patterns and working on your logistics in fishing weather patterns.