Possible Clues:

• Co-ordinated attack on prey
• Aggressive, predatory attack
• Period of intense competition
• Uncontrolled competition for limited resources
• Collective attack by a shiver of sharks?
• Sudden intense excitement
• Situation where many predatory fish attack a food source
• Fierce competition for a limited resource
• Period of violently excited competitive activity
• Competitive attack on same prey by a number of predators