Which term describes a defensive formation of small fish in a dense ball?

Which term describes a defensive formation of small fish in a dense ball?

• A. Photophore cluster
• B. Shoal
• C. Bait ball
• D. Anadromous

Answer: (C)

When small fish group defensively in a tight, swirling ball, that formation is called a bait ball. The idea behind it is to protect the school: packing into a dense sphere makes it harder for a predator to single out and grab an individual, and the chaotic, fast movements create confusion that helps species within the ball slip away. A shoal, by contrast, is a looser, more spread-out gathering of fish, not a compact defensive ball. A photophore cluster refers to a group of light-emitting organs used by some species for signaling or camouflage, not for forming a protective ball. Anadromous describes fish that migrate from saltwater to freshwater to spawn, not a defensive formation.

When small fish group defensively in a tight, swirling ball, that formation is called a bait ball. The idea behind it is to protect the school: packing into a dense sphere makes it harder for a predator to single out and grab an individual, and the chaotic, fast movements create confusion that helps species within the ball slip away. A shoal, by contrast, is a looser, more spread-out gathering of fish, not a compact defensive ball. A photophore cluster refers to a group of light-emitting organs used by some species for signaling or camouflage, not for forming a protective ball. Anadromous describes fish that migrate from saltwater to freshwater to spawn, not a defensive formation.