Mysterious predator

I refer to the letter by Tony Gatt regarding the danger of fish farms attracting large predatory fish, where he mentioned the death of Jack Smedley (not Tom Ashby). While I have no intention of entering into the fish farm controversy I would like to comment on the so-called shark incident.

The "attack" happened on July 20, 1956 and the person accompanying Mr Smedley was Anthony Grech, a student of Mr Smedley, who was a teacher at the dockyard school.

In an interview given to It-Torca of March 8, 1981 Mr Grech recounted how the large fish passed under him during the attack and how he pushed it away. But a most puzzling part of the interview is when Mr Grech stated that when he emerged from the water he noticed what appeared to be fish scales attached to his chest where the large fish had rubbed against him. Sharks have no scales like other fish. They are covered in shagreen, a type of sandpaper-like tissue made up of millions of minuscule teeth called dermal denticles.

In fact, this skin was used by carpenters in the past instead of sandpaper. A shark rubbing against you would take away your skin rather than leaving his attached to you! This part of the story has been puzzling me ever since I read the interview.

Could the attack have been made by some other, yet undisclosed predator?