A 34-year-old Cordova man was found dead on a fishing boat in Prince William Sound Monday, the Alaska State Troopers said.

The man, identified as Sean M. Johnson, was aboard the F/V Northern Mariner.

The vessel was longlining for Trident Seafoods, said Alaska State Troopers spokeswoman Beth Ipsen.

Authorities believe Johnson died sometime between midnight and 5:30 a.m. and was found by crew members.

An autopsy will be performed to determine the cause of death.

The U.S. Coast Guard is investigating the incident.

Reach Michelle Theriault Boots at mtheriault@adn.com or 257-4344.