Building an almost 1 acre pond. Mostly for swimming + boating / floating. I'm concerned about damage to the HDPE liner from the neighbouring turtles, otters and muskrats et al.

I would like to put geo throughout the basin but that floats. I can put rock down on a fair bit and also thinking a concrete / mortar mix to weigh it diwn but are these my only options ? Is there a sinking protective fabric ? Are people seeing damage from animals with there liner installs ?

Thanks