The boat, operating out of Tabusintac, issued a distress call at around 5:30 a.m. local time Saturday. Three crew were on board when it capsized.
The body of a 23-year-old man from nearby Tracadie-Sheila was later found on a beach near where the boat got into trouble. At about 4 p.m., RCMP took over the operation as a missing persons case.
Spokeswoman Cpl. Chantal Farrah said RCMP officers, Tri-County Ground Search and Rescue and teams from Miramichi and Restigouche, as well as local fishermen and residents, were combing the shoreline for any sign of the two crew members Saturday evening.
"This is very difficult for all the families involved and we appreciate the efforts from the entire community, who really came together today to help search for the missing men," said Farrah.
Farrah said officials would continue to look for signs of the missing men on Saturday until there was not enough visibility.
Dozens of vehicles parked near the wharf as they awaited news.
Bad weather, cold seas
Mike Bonin of the Joint Rescue Coordination Centre said the weather was bad at the time of the mayday call.
Bonin said they sent a Cormorant search-and-rescue helicopter and two Coast Guard vessels to join local fishermen searching for the crew. RCMP conducted a ground search. The air and water efforts were stopped at about 4 p.m. local time.
"Despite our best efforts, an exhaustive search and after repeating the search pattern area several time, unfortunately there was nothing more that we could do to find these people," he said.
The boat apparently hit the sandbar in rough seas and began taking on water. Bonin said the crew members were not wearing life jackets. The two missing men are thought to be in their 40s or 50s.
"The report was the vessel had run aground. We had reports of three people on the vessel, and they were standing on the hull of the boat trying to get rescued," Bonin said Saturday afternoon.
The sandbar is about four kilometres from shore. Bonin said the vessel is still visible on the sandbar.
Boat gutted in fire
A New Brunswick Conservative politician said the captain of the vessel had rented it after his fishing boat was destroyed in a fire earlier this month.
Serge Robichaud, who represents the Miramichi Bay-Neguac area, said the captain's boat was one of five vessels that were gutted by a blaze at the Tabusintac Wharf on May 5.
He said the community was in mourning and hopeful that the remaining two fishermen would be found safe.
"This is a small community," said Robichaud from the Miramichi area on Saturday. "It's a tough job, to be a fisherman. Rain or shine, you still need to go and I guess this morning when they left, they were at the wharf early and it was rough."