Fishinut: the problem is that with the cool nights, the shorelines have the greatest fluctuations in Temp....
the same way they will heat up the most in the lake under the midday sun, they will cool off the most overnight right now.....
it is a combination of water temp/and/or feeding opportunities.....
in lakes where turnovers have occurred, there is now a more even water temp throughout......
think about this: if you are a fish sitting in a lake, and the water temp is 50 degrees on the shorline, and 50 degrees 20 feet down.....why would you be on the shoreline, where: anglers can pick you off easily, cormorants and herons can pick you off easily.........
remember: although the bass is a predator, he is also predated himself and a lot of his activity is designed not only for ambush or feeding opportunities but for his own protection......
when the feeding opportunity ONLY exists shallow, then he will have to take that risk , or when hormones and instincts are pushing him shallow to spawn, then alright....
but under normal circumstances, as long as there is reasonable feeding opportunity down deeper, he himself is much safer down there.....
that is why I mentioned in Pug's example, Tibbets Brook Pond: if the water shoreline is 3 feet and the water in the middle of the pond is 3 feet, it is much safer and secure for those fish in the middle of the pond....
if there is an exceptional feed opportunity ( crawfish ) shallow, they might take the risk, but otherwise, there is nothing to be gained by being shallow.......
when a bass lurks in the shadows, it is also for his own protection as well as ambush....keep that in mind.....
two things will drive a bass shallow: Spawning urges and exceptional feed situations......
in all other cases, he has way more to lose by location shallow.....