Possible Clues:

• Long marine fish
• Slim predatory swimmer
• Predatory fish
• Farewell to what angler has on rod to get fish
• What's gone wriggling into fish basket?
• Large slippery fish
• Big fish in creel gone bad
• Fish that's gone berserk in the angler's basket
• Dismissal is to stagger swimmer
• Sharp-toothed Atlantic swimmer