this is what im seeing, the bottom darker spots are around 100 feet, i think those are the adult smelt, i see those everywhere in the lake, the top cloud i believe is the yoy, very few on the lake, this cloud tapered up into ten feet under the surface but there was just too much glare to get a pic. water temp was 77 and the pic was taken at noon on a hot bright day. i dont think adult smelt will be in water that warm, they must be the yoy and they are few and far between this year on sebago, last year when the water was this warm that school was 3 miles long, maybe its just too early just yet
i remember the first year that i fished there (2006) there would be a constant ribbon of them deep on the depth finder. Like you say it was all over the lake. At first I thought it was my down rigger weights but they were up alot higher. Couldn't believe how long a stretch it would run.