Four of the men missing last night on the stricken trawler, Pere Charles, live in the Dunmore East area, a fisherman at the port said last night.
Friends, relatives and other locals gathered at the harbour, where fishermen were unloading herring from a boat that had just come into port.
One of the fishermen, Darren Walsh, from Cornwall, England, said he was supposed to be on the Pere Charles yesterday. However, because he was busy, the boat had been unable to wait for him.
Mr Walsh said he believed that the Pere Charles had five crew on board.
Among the men he said were missing are Pat Hennessy and Tom Hennessy, both from Co Kerry, who have lived and worked in Dunmore East for many years.
He said Billy O'Connor and Pat Coady from Dunmore were also on the boat as well as an eastern European man.
Mr Walsh said the Pere Charles had gone out at 4am to fish for herring and would normally be expected back by midnight.
A local man at the harbour, who declined to be named, said that it was "starting to blow" and it would be "rough" conditions for the sailors. He said he knew four of the missing crew members.
A spokesman for the RNLI, Nicho Murphy, said that the Dunmore East lifeboat was out with a crew of seven people. He said the search was also being supported by the Kilmore lifeboats and two helicopters. He said fishing boats which had been operating in the area were also searching.
Mr Murphy said: "It's an awful situation, as we know all the lads. Conditions are bad. The forecast is for storm force winds later and the search will be hard."
He also said that because of deteriorating conditions, the smaller fishing boats which had gone out to assist with the search would have to return to harbour.
One of the men missing, Tom Hennessy, is in his early 30s and is married with two daughters, according to people gathered at the harbour last night.
He is a nephew of Pat Hennessy, who is believed to be in his early 50s.