A Millinocket man died in a kayaking accident Sunday afternoon on Nesowadnehunk Stream south of Baxter State Park, the Maine Warden Service said.

Joseph Giffune Jr., 25, was whitewater kayaking with a friend just after 5 p.m. on a section of the stream just above the West Branch of the Penobscot River when he got stuck in a hydraulic gap at the bottom of some ledges and was unable to free himself, Cpl. John MacDonald, a warden service spokesman, said in a statement.

Hydraulics, or holes, are formed when fast water flows over a submerged boulder or ledge, causing the water on the surface to flow back upstream. People can get trapped under the surface in the powerful, recirculating current.

Giffune’s companion tried unsuccessfully to rescue him. Eventually the hydraulic released Giffune, and he was swept downstream into the West Branch.

Giffune was unconscious when he was pulled from the river. Life-saving measures were unsuccessful and he was pronounced dead at the scene, MacDonald said.

Millinocket rescue personnel assisted game wardens at the scene.

Giffune’s family said in a statement late Monday afternoon that it was “deeply appreciative of the expressions of sympathy received from Joe’s many friends. Joe was an experienced whitewater kayaker and rafting guide who died doing what he loved in the place that he loved.”