The number of towboats reported out of action on inland waterways declined Wednesday with minimal disruption reported at one of the largest U.S. ports as a pilots' strike entered its fifth day.

About 226 tugs were tied up at midnight Tuesday on the Mississippi and other critical waterways, according to William Warwick, a spokesman for the union Pilots Agree.That is down from the union's estimate of almost 300 tugs on Monday. But Mr. Warwick said towboat companies had to stretch thin to replace pilots who walked off after the companies refused to discuss pay, working condition and safety issues.

''They're getting back recently retired pilots, pilots on medical disability and former pilots who have been working at desk jobs, maybe for five or 10 years,'' he said.

The Port of South Louisiana in Baton Rouge, La., the nation's largest port in terms of volume and exports, reported the loss of traffic has held steady at about 3 percent since the start of the strike.

''It hasn't been the Armageddon we thought it could be,'' said Gary LaGrange, the port's executive director.

Coast Guard Lt.j.g. Jay Caputo said the Coast Guard was investigating claims of unsafe practices by towboat companies made by Pilots Agree's parent, the International Organization of Masters, Mates and Pilots Association.

But the American Waterways Operators said companies could easily fill the relatively small number of vacancies. There is a large pool of independent contractors called ''trip pilots'' who fill in when needed, said Ken Wells, New Orleans-based vice president for the AWO southern region. Any former pilots called from desk jobs are highly qualified, he said.

Noting that the inland towboat sector includes about 3,800 tugs in some 400 companies, Mr. Wells said, ''As an industry, the strike is not really a concern.''

Only a few problems had emerged at the Louisiana port after dockworkers refused to cross Pilots Agree picket lines, he said.

Dockworkers who walked off at the Port of New Orleans early Monday returned by 6 p.m. Monday and have been working since, said Paul Dauphin, a port spokesman.

The Coast Guard reported 32 tugs tied up as of noon Tuesday, down from 54 Monday afternoon and 71 on Sunday. Mr. Caputo said this is not an exact count of boats affected by the strike because the Coast Guard is concerned only with boats that pose a safety hazard.