A man drowned after falling overboard in the Port Isabel Ship Channel, Cameron County Sheriff Eric Garza said Monday. 

Garza said the 56-year-old man, who has not been identified, was tying his boat to a marker when he fell. He was not wearing a life vest.

The man's 18-year-old son was unable to save him due to rough conditions, Garza said.

The man's body was recovered by the United States Coast Guard.