They may also roost on mudflats, sandbars, beaches, reefs, jetties and pilings. Shoals are also known as sandbanks, sandbars, or gravelbars. Sandbars with large dunes form lagoons and coastal lakes along much of the coast. They live in and around inlets, points, jetties, and sandbars. Formation of such sandbars is now managed by a system of jetties. The Po Delta to the south features sandbars and dunes along the coastline. The sandbars shift due to rough waves and unpredictable currents. There are a multitude of shifting tides, water depth, and new sandbars throughout the year. Concepcion is a host to beautiful islands with white sand beaches and sandbars. Successful germination often occurs in large numbers along sandbars, where alluvial soil is present. A beach break happens where waves break from offshore waves, and onshore sandbars and rips. It breeds on sandbars in very large rivers. One may fish from banks, sandbars and islands, or from boats. Fishing, camping, and picnicking are legal here, including on the sandbars. The harbour entrance was particularly troublesome with constantly shifting sandbars.