HAVERHILL — Harbormaster Michael Vets, firefighters and police officers joined forces Wednesday evening to rescue a man who had ventured into the Merrimack River.

The Fire Department received a call at 5:59 p.m. that a man had “entered the river” near Merrimack River Park, formerly the Hannah Duston Rest Area, on Route 110, according to Deputy Fire Chief Eric Tarpy. He was not sure whether the man, estimated to be in his 40s, jumped or dove into the river or waded in, Tarpy said.

Engine 4 from the Bradford station was dispatched along with Vets in his boat. The unidentified man swam to the other side of the river and got out of the water, but the terrain there is treacherous and difficult to negotiate, the deputy chief noted.

Rescuers placed the man in a Stokes basket and pulled him upward along 300 to 400 feet of rough terrain, Tarpy said. The man emerged from the river near the Covanta refuse plant. The area is wooded and rocky.

An Amesbury police K-9 unit helped find the victim, Tarpy said. Massachusetts State Police troopers also assisted in the rescue. After he was brought to safer ground, he was transported by Trinity Ambulance to a hospital for evaluation.

Tarpy declined to comment on why the man went into the river, which is noted for having strong and potentially dangerous currents. Rescuers cleared the scene around 9 p.m., he said.

“It was a challenging rescue,” Tarpy said. The rescue succeeded because of “great teamwork” among the first responders, he added.

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