Possible Clues:

• Party with measure of acid nothing to be upset about? One jumps in the water laughing
• Sea creature pictured on the flag of Anguilla
• Sea-mammal with a beak-like snout
• Creature at sea, old, injured flipper, we're told
• Intelligent swimmer working on DPhil?
• Small gregarious toothed whale
• Bottle-nosed mammal
• Small toothed whale, larger than a porpoise
• Marine mammal with an elongated beak-like head