Television cameras rolled Monday at the annual Labor Day picnic as hundreds of union longshoremen lobbed Del Monte pineapples into the Delaware River at Penn's Landing, angry at the company's decision to switch its banana-shipping business to a different port, where workers earn less.

Away from the cameras, a handful of off-duty Penn's Landing security guards gathered just outside the main gate. Two weeks ago, they filed a petition to form a union, and since then, they say, their hours have been cut in retaliation.

That's how it was this Labor Day in Philadelphia: one group desperately trying to keep good jobs at a time when nearly one in 10 Americans is unemployed, another group trying to overcome obstacles to become unionized.

As usual, labor-union members paraded on Columbus Boulevard, forming a long rainbow in their colored T-shirts - dark green for city employees, purple for janitors, Jerry Garcia tie-dye for hospital workers.

As usual, the Teamsters led the parade, driving big rigs, and politicians came by to shake hands.

And also as usual these days, labor leaders worried about how to stop the erosion of union jobs in an era when workers make concessions to stay employed, even as they talk tough and vow boycotts.

"We will not sit here and let Del Monte take our jobs," Boise Butler, president of Local 1291 of the International Longshoremen's Association, said as the pineapples flew and the crowd cheered.

Stephen Mullen, 28, of South Philadelphia, and his 8-year-old daughter, Madison, were part of the longshoremen's group.

"I'll probably lose my job," said Mullen, a fifth-generation dockworker.

Starting Oct. 1, the longshoremen's union will lose 400,000 labor hours a year - the equivalent of 200 to 300 jobs - when Del Monte Fresh Produce Co. shifts 75 ships and a half-million tons of banana cargo from South Jersey Port Corp. in Camden to privately owned Gloucester Terminals L.L.C.

Mullen earns $24 an hour, working up to 14 hours a day unloading Del Monte fruit. At the height of the season, two ships a week come to South Jersey Port Corp.

Of course, Butler said, the union is upset about the loss of work for its members, but it's not just about the union. "Our jobs are family-sustaining jobs," he said.

The union says the Gloucester workers are paid below industry standards - between $10 and $17 an hour.

With concessions that the union offered Del Monte to keep the business, dock and terminal workers would have earned $21.50 to $22.50 an hour, down from a top rate of $31 an hour. Besides the pay cuts, they had agreed to changes in work rules and staffing.

Leo Holt, whose family runs the Gloucester facility as well as the Packer Avenue Marine Terminal in South Philadelphia, declined to discuss wages in an earlier interview, but said his employees earn more than $12 an hour.

Neither Holt nor Del Monte returned requests for comment about Monday's events.

Like dockworker Mullen, Penn's Landing security guard James Walsh, 54, lives in South Philadelphia. The father of four, he holds two jobs - overnight security at a hotel and an $8-an-hour daytime job patrolling for Delaware River Waterfront Corp.

On Aug. 23, Walsh and four of the six guards signed cards and filed a petition with the National Labor Relations Board. They want an election so they can vote to join the Philadelphia Security Officers Union, which represents guards at the Philadelphia Museum of Art.

The guards say they'd like more money and benefits.

After the petition was filed, Walsh said, he was cut to four days. Next week, for the first time since he started 15 months ago, he was assigned a Saturday night shift, which he said his supervisor knows will conflict with his other job.

"I believe they want to get rid of us as security guards before we have the opportunity to vote," Walsh said.

Waterfront Corp. vice president Joe Forkin denied retaliating against the guards.

"I don't believe that to be true," Forkin said. "We have to go through the [election] process."

Patrick Eiding, head of the Philadelphia Central Labor Council of the AFL-CIO, said the guards' experience is all too typical. "From the time they sign the cards to the time they hold an election, the employer has all kinds of ways of intimidating employees," he said Monday.

Though the tales of the guards and the dockworkers are not over, Monday's picnic ended midafternoon as pineapples bobbed in the river.

Mullen, Butler, and the other longshoremen were angry.

At Del Monte and Holt's request, they had agreed to cuts. The State of New Jersey had promised to add warehouses in Camden and had agreed to subsidize Del Monte's electric bill, they said.

"This is a disgrace," Mayor Nutter said in an interview at the parade, adding that he had sent a letter to Del Monte, and that Gov. Rendell would be calling the Holts.

"Something's not right here," the mayor said.