Fish finder help - what are these??

[try'n hard]

Admit to knowing very little about crappie and less about fish finder ID but these white dots ran me in circles this morning. This is from the mouth of a Creek that feeds into the main river. Water is 10' here and 40' thirty yards out in the river. I fished these with every color jig I had. There were lots of schools each with about twenty fish and were all suspended between 6' & 8' I got no bites. What y'all think these are?