SANDY HOOK, N.J. (CBSNewYork) — Helicopters, dive teams and the U.S. Coast Guard converged on the Sandy Hook Channel off the New Jersey shoreline Tuesday night, after reports of a sinking fishing boat.

The Coast Guard received a call from the captain of another boat about a vessel in distress around 4:30 p.m. The boat in distress was described as a 40-foot fishing trawler taking on water off Lower New York Bay.

The Coast Guard was told the boat sank shortly afterward. The captain of another boat, Kevin Bradshaw, told CBS2 he clearly saw the fishing boat sinking but declined further comment.

PHOTOS: Search For Missing Boat Near Sandy Hook, N.J.

As CBS2’s Dave Carlin reported, NYPD Divers went in to the Sandy Hook Channel as rescue helicopter teams scanned the water from above, searching for the trawler called the El Jefe.

The Coast Guard was joined by the NYPD Special Operations Unit, the FDNY, the New Jersey State Police and the Monmouth County Sheriff’s Office in the search.

Rescuers arrived to find only small clues bobbing on the surface, including a life ring and a cooler. But before sunset, they also found floating oil that could have come from a boat in distress.

After dark, divers finished for the night and the search relied primarily on side scan sonar, the high-tech tool that sees objects in the water that the eye alone cannot.

Ryan Radice and his fishing buddies watched the massive operation unfold.

“All the ambulances and everything, and then we started seeing the boats and the helicopters out in the water,” said Radice, of Scotch Plains, New Jersey. “We did talk to a guy – a guy and his wife who do see the boat go down, like a fishing boat, but it was too far out in the water for them to really see anything.”

“It is tragic,” Radice said. “There is nothing good about it.”

The search zone in Sandy Hook Bay was about 70 feet deep, the Coast Guard told 1010 WINS.

The search ended had for the night by about 9:45 p.m. and was to resume Wednesday morning.