Could those be ammonia burns? Turns out the shark was shipped with ammonia levels already at .25 when bagged. Vendor said its fine for sharks to be in ammonia .25 to .35. I said it should be zero.
Ammonia is more damaging to the fish's gills. When you see water quality issues in sharks, it often shows as petechia - red spots.
Do you know what the ammonia was at the end of the shipment though? I agree 0.25 ppm isn't an issue for sharks short-term, but it could have been much higher by the end of the shipment if it took the typical 24 to 36 hours for shipping time.
Jay