Exactly, PVC gets brittle with continued exposure to sunlight. Besides, I don't want the crap marked. I want it removed. It's those little 2 inch long pieces just underwater that tear you up. They could lower the lake level, and cut off the tops of the stumps. Most of these are only a few inches in diameter and are in 8-24 foot of water, so i do not see how removing 18-24 inches could hurt anything.