1. shallow areas of water, especially those that are dangerous to ships
Usage: nautical
2. large groups of fish swimming together

Examples

• The captain carefully navigated around the treacherous shoals near the harbor.
• Many ships have run aground on these rocky shoals over the centuries.
• Shoals of herring moved through the coastal waters during migration season.
• The fishermen followed the shoals of tuna across the ocean.
• Warning buoys marked the location of dangerous shoals in the bay.
• Massive shoals of sardines attracted dolphins and seabirds to the area.