We have since learned that Bull Sharks are very well adapted to fresh water and sea water. It is now the season that Bull sharks migrate to the lagoon to give birth.Bull sharks are also notorious for head butting their prey before attatck- which is exactly what happened to our poor friend.She can describe the light grey top and white bottom very clearly.So everything points to the Bull Shark. I have given up googling "Bulll sharks" as I still want to enjoy my time in the sea. Take Care out there Tracey xxx