Here you can get an idea of how many eggs are in a ribbon by counting up all the white dots and extrapolating the ones you don't see if you have too much time on your hands. LOL
In this case the white dots are unfertilized eggs that are dead due to a lack of males in the pond - on purpose.
This ribbon was about 4 to 6 feet long from a perch somewhere in the 13 to almost 15 inch range, which is 90 percent of the ~ 300 yellow perch in this pond.