The lunitidal interval is the time between the occurrence of high tide and the next low tide, or vice versa. It varies from place to place due to factors such as the shape of the coastline, the depth of the water, and the strength of the tidal currents. In general, the lunitidal interval is shorter in areas with a narrow continental shelf and stronger tidal currents, and longer in areas with a wide continental shelf and weaker tidal currents.