Dillingham, Alaska (KINY) Grant Hildreth Jr, 25, was working on a fishing vessel.
Alaska State Troopers said several agencies have responded to the scene that include the US Coast Guard, and the Pilot Point Village Public Safety Office.
The fishing vessel Cape Greg also has assisted in the search on the Ugashik river.
Troopers said the preliminary investigation found Hildreth went overboard at 4 pm Thursday and hasn't been seen since. Crew members attempted to get a flotation device to Mr. Hildreth but he went under the water. He was not wearing a personal flotation device at the time of the incident.
Assets from the USCG remain on scene and are searching for Hildreth along with area vessels.