The Sparkle Blue is what is refered to by Sharks to mean death. Shark-kind say to 'swim the sparkle blue' which means they have died. The Sparkle Blue may refer to the sky which under the waves appears rippling and may 'sparkle'.
List of known Sharks who have Swam the Sparkle BlueEdit
The Sparkle Blue Hokuu
Poole (a whitetip reef shark originally from Jetty Shiver)