Update... The holes in the bank go quite deep and I think some may even connect to some others. With the water level down I think the holes are abandoned, or may have been abandoned some time last year with the dog at them all the time. He must still smell them or want to see what is in there as he was always trying to expand the openings to get in there.

No muskrat activity..

I filled them in with left over rocks from my landscaping (2" egg shape) and tried to pack as far back as I could under the banks, then covered that with dirt. HOpefully the rocks will keep the dog from enjoying digging the fresh dirt back up again.

No rain in the forecast so I'm pumping up the water level with my house pump and soon these areas will be under water. We'll keep a close eye out for new holes.

I'd love to have my dog catch those rascals if they ever return.

I'm now hoping that the lack of turtles this spring isn't because the dog is always prowling the pond. I imagine turtles can't move quickly and the dog can chase them into the water too. They may have smelled the dog and headed to another, quieter pond. I hate to do it but with the dog dirty and wet all day I may have to put a loop of underground fence around the pond. I keep stalling as the dog loves wading and chasing anything that is in the shallows and he is great at chasing away GBH as well. Not to mention when it is hot (black dog) he loves to cool off.