Okay, what happened?!!

four days ago under a semi cloudy sky - good numbers
water temp 48; air temp 60; 9 or less mph wind from the sw
yellow perch done with spawn (pretty much)
45+ fish caught (3 species); 6 nice crappie
Fish found on a 50 yd line connecting two shoreline markers -anchoring and casting every 30', most caught in 6'
float bite good

today 54 degree water
fish scattered - only a few good ones
mostly small crappie, a few perch and sunnies - two dozen+
bluebird sky, same wind except from the n.e.
air a chilly 50 degrees
only 3 fish on the float and jig


What gives? Transition happening?