Credit: History Channel

Swamp People star Mitchell Guist's untimely death--just before his 49th birthday--has left friends, family, and fans of the History Channel program stunned.

"We are extremely saddened to report that our friend and beloved member of the Swamp People family, Mitchell Guist, has passed away," a History Channel spokesperson told the Associated Press in a statement Monday. "Mitchell passed on the swamp, doing what he loved. We appreciate your respect for the Guist family's privacy and hope you join us in sending our thoughts and prayers to his brother, Glenn, and the rest of the Giust family."

Giust was on his boat in a St. Martin Parish waterway around 9 AM Monday when he fell. Concerned witnesses called 911 and Guist was transported to an area hospital, where he later passed away.

One of the 911 callers who attempted to revive Guist told responders they were doing their best to resuscitate the reality star. "It looks like he may have had a heart attack," the caller reported.

At this time, no official cause of death--or reason for Guist's initial fall--is available.

On Swamp People, Mitchell Guist and his brother Glenn Guist--both residents of Louisiana's Atchafalaya swamp--took cameras along during alligator hunting season for the History Channel program.