April is a time of weather extremes and those cold extremes can shut down shallow water springtime fish species. Fishing success can be impressive during warming trends, only to go into a downward spiral with the next cold front. Pymatuning Lake, Shenango Lake and Allegheny River have seen hot bites go up and down the past two weeks. With the perch spawn pretty much over in Presque Isle Bay, anglers await the main arrival of smallmouth bass.