Federal and local law enforcement agents wrapped up a two-day exercise Thursday simulating a possible mass exodus from Cuba after Fidel Castro's death, but exile leaders and Cuba experts said such a scenario is unlikely.

During one simulation, nearly a dozen government vessels maneuvered past cargo, cruise and fishing boats three miles off the Fort Lauderdale coast to apprehend a 26-foot boat carrying mock smugglers who were supposed to be armed and headed to Cuba to pick up migrants.

That simulation began just hours after a real U.S. Border Patrol mission picked up more than 40 Spanish-speaking migrants who happened to arrive Thursday morning along Miami-Dade beaches. Arrivals like those occur frequently in South Florida, the majority of them from Cuba.

Still Cuba experts said they don't expect massive waves of migrants like 1980's Mariel boatlift — even after the death of Castro, who transferred power to his brother Raul last July because of ill health. More than 124,000 people were stopped at sea in a six-month period during the Mariel crisis, which was triggered when Castro said anyone who wanted to leave the communist island could.

"Forget it. It ain't gonna happen," said Jaime Suchliki, a University of Miami professor and the author of "Cuba from Columbus to Castro."

"Raul would have to say, 'Anyone who wants to go, go,"' Suchliki said, and such a move would desermitted to ride along, the script began with a mock 911 call to the Broward County Sheriff's Office that armed boaters were headed south to Cuba. Sheriff's deputies were to alert federal, state and other local officials who were in the area and could respond.

By 10:30 a.m., two helicopters and nearly a dozen boats from the Coast Guard, U.S. Customs and Border Protection and local law enforcement trailed the "smuggling" craft, flashing lights and ordering the boat to stop.

Agents did not attempt to board the smuggling vessel because of choppy seas, nor did they attempt to snare or disable it so as not to give away tactics, said Customs and Border spokesman Zachary Mann.

"The reality is we have the assets and the manpower. If we have to make that stop, we will make that stop," he said.

Authorities said they were pleased with the exercises but planned to review the training and make necessary adjustments. The need for a few tweaks to the plan quickly became clear after authorities created brief chaos by declining to choose the media outlets for the ride-along and urging dozens of members of the press to decide among themselves. Also, while Thursday's show of force was aimed at deterring mostly Cuban smugglers and migrants, officials failed to provide fluent Spanish-speakers for the large number of Spanish-language media that attended the ride-along.

With 85 federal and state agencies participating, the training marked the largest such exercise since a 2003 presidential directive created the Homeland Security Task Force Southeast to better police the nation's southeastern borders.