Schooling and aggregating behaviors are apparently associated with increased feeding and vulnerability to angling. When the barometer was high, 54 percent of the bass observed were aggregated (groups of 3 to 15), 12 percent were schooled (moving synchronously), while 44 percent were alone or paired. When the barometer was low, 57 percent were aggregated, 5 percent were schooling, and 38 percent were single or paired.

When the barometer was rising slowly, 64 percent of observed bass were aggregated, none were schooling, and 36 percent were paired or alone. When barometric pressure was falling slowly, 53 percent were aggregated, 20 percent were schooled, and 28 percent were alone or paired. If it weren’t for other factors affecting bass activity, the data might suggest that a falling barometer, approaching storm, increasing cloudiness, or a combination of these and other factors increased feeding activity.

Use of Cover

How about cover? With a steady barometer, 34 percent of observed bass were within 1.5 feet of cover, 31 percent more than 6 feet from cover, and the remaining 35 percent were in between. A slowly falling barometer found 30 percent in or close to cover, 25 percent away from cover, and 45 percent in between.

During a slowly rising barometer, 30 percent held close to cover, 30 percent away from cover, and 40 percent in between. Barometric pressure changes didn’t provide a positive clue to bass location relative to cover. The data did, however, demonstrate that most bass are away from cover and suspended most of the time in a clear wood-deprived grass-free highland reservoir like Lake Travis.

We also monitored the location, movement, and apparent feeding of bass under various cloud conditions. Under overcast skies, bass were observed farther than 46 feet from shorelines in 23 percent of cases, while 19 percent were offshore under broken skies (50-80 percent sky coverage), 33 percent under scattered clouds, and 32 percent under clear skies.

Our bass apparently found little difference between partly cloudy and clear daytime skies, but most likely moved offshore under bright sunlight. Feeding was seen under overcast (42%), broken (23%), scattered (24%), and clear skies (28%). While overcast skies were clearly associated with increased feeding, clouds, even a broken ceiling, had little effect.

The low light of heavy cloud cover apparently makes preyfish more vulnerable to predators and encourages bass activity. Surprisingly, we documented slightly more feeding activity under totally clear skies than under partial clouds. The maximum brightness of clear skies, which creates optimum feeding opportunities for plankton-eating prey, likely encourages maximum preyfish activity, which in turn may stimulate increased predation.

When we analyzed the relationships between weather trends and bass proximity to cover, no trends appeared. Virtually the same percent held close to cover before and after a frontal passage, though more were found in cover after the front passed. Bass behavior seems determined by many variables, with no single factor like barometer reading, barometric change, sky condition, wind speed, wind direction, or even prey availability compelling bass to be active or inactive.

We monitored all of these variables and many others without finding any single factor that was a reliable predictor of feeding or striking activity by black bass. At any given time, some bass were inactive, some neutral, and some active. Small catches result when the percentage of inactive bass increases, while larger catches result when a few more fish decide, for whatever reason, to actively seek food.