I had eel grass in my pond that was doing great. I had it started in plastic tubs, and pushed it out to deeper water so it'd survive the winter. Spring came, Spring snowmelt/rains didn't. Pond level dropped. Tubs were doing well in 12"-18" of water. They're fine I said to myself.
Then I came home and saw 40 Geese on the pond. Chased them off and noticed that the tubs were empty. Guess what the geese ate??
Yep, roots and all.............