1. became shallow or made shallow
Usage: nautical
2. moved in a large group
Usage: used of fish

Examples

• The water shoaled as we approached the reef.
• The river shoaled during the drought.
• Fish shoaled near the surface at dawn.
• Herring shoaled in massive numbers off the coast.
• The bay shoaled over decades due to sediment buildup.
• Sardines shoaled together for protection from predators.