A call came in around 11:40 a.m. Monday for a 29-year-old man who was ejected from a boat in the mouth of Gibson's Creek in Upper Township.
Ocean City Police say two men were in the boat when it hit a mud patch.
The other man in the boat landed on the mud, and tells rescuers he saw his companion go under the water.
Rescue boats and a helicopter are being used in the search.
The identity of the missing man has not yet been released.
