I'm not sure I understand the harm from the sun. When perch eggs hatch in MI at ice out, the sun is low enough on the horizon yet that you could not get enough UV on your bare skin to create any redness or tan no matter if you were out all day. I doubt UV index is very high.

Also, my perch eggs are in 6-10" of water and hatched fine. I don't think you can control how deep they lay their eggs, they tend to find the spot they like and put them there.

Others might know more about the UV connection to egg survival.