Southern Stingray Injury

Hello!
I work at a small aquarium, we have several 500+ gallon tanks including a touch tank with both Southern and Atlantic Stingrays. I came to work today to find my largest girl, a southern, with a huge chunk of her barb separated from her tail. I do trim their barbs with clippers about every 3-4 months and I'm thinking that is what another employee was attempting to do. I just don't have any other explanation as to how this injury could have happened.
Regardless, I am posting to you all with your great wisdom as to how to treat the wound with the best care? Is there a particular marine adhesive to help re-attach the skin and aid in healing?
Any suggestions would be most appreciated!!
Thanks so much! Love the site.