Uhhh-anyone here ever see a dog with gills?
If you dragged a dog behind a boat hooked like that I guess he'd last about....oh... 30 seconds. Plus the muzzle area is far too clean for the kind of trauma inflicted. No swelling, blood, hair loss, tears. This is bull*****.
Besides, if you read the snopes article, they said that anything that hit the water was dead already. Apparently sharks like blood, so tossing a butchered carcas in the water probably works pretty well. If they kill a dog (ahead of time) to do this, I think that's not very nice, but many cultures consider dogs simply a food source. My dog is a family member and protector, but that's me.