The search for a man who jumped into Rock Creek in Anne Arundel County on Sunday and never resurfaced turned into a recovery mission Monday, according to Maryland Natural Resources Police and first responders.

Natural Resources Police responded Sunday to a report of a missing boater near the mouth of Rock Creek by Harry and Jeanette Weinberg Park in Pasadena around 4:15 p.m.

The man, who has not yet been identified by authorities, was out on a pontoon boat when his hat fell into the water, said Vincent Dortenzo, a spokesperson for the state Department of Natural Resources. The man was not wearing a life vest when he jumped into the water to retrieve the hat.

Dortenzo said the man was on the boat with six other people, who called for emergency assistance.