Dreaming of training a dolphin? Now you can make your dream a reality!

As Marcella Sertich walked into the Shedd Aquarium early one Saturday, she confided, "I've always wanted to work with dolphins, ever since I was little."Sertich, 24, has a sensible college degree -- business -- and a sensible job, as an administrative assistant. But when she isn't typing memos and answering phones, she dreams of dolphins leaping at her command, tracing perfect arcs against the sky.

Two hours later, as the Hoffman Estates resident balanced on an outcropping in the Shedd's Oceanarium, scrubbing algae off the rocks, she had an epiphany: Dolphin work isn't as romantic as those "Flipper" reruns would have us believe."I actually thought other people took care of the cleaning," she said later.That realization alone may have been worth the $350 Sertich paid to participate in the Shedd's Trainer for a Day program.

She'll still pursue her dream -- she's taking biology courses at a community college -- "but now I know the details of what [trainers] actually do, and how much cleaning and food preparation there is before they actually work with the animals," she says.The 18-month-old program is a hands-on answer to the countless aquarium visitors who wonder what it's like to be a trainer.

It's also one of the more creative initiatives that the city's museums have launched in recent years -- along with sleepovers, day camps and even rock concerts -- to boost their bottom lines.The morning I joined Sertich to try the program, I leapt out of bed long before my alarm sounded the high-decibel wail usually required to awake me for work. This morning, in fact, felt like Christmas: I could hardly wait to fulfill my visions of learning hand signals, helping teach a dolphin a dazzling trick, and tossing a few perch to a hungry beluga whale.

When I arrived at the Shedd at 8:30 with Sertich, though, we received an ominous welcome. "You're going to be doing exactly what a trainer would do on a typical day," said an administrator, ushering me through the employees' entrance. "Only 25 percent of a trainer's time is actually spent with the animals."Uh, oh. This was starting to resemble the Christmas when I opened a beautifully wrapped gift from my mother, only to find, inexplicably, several bottles of shampoo.

Sertich and I were given clothes to change into: elastic-waisted khaki pants, a blue T-shirt and knee-high rubber boots. My reflection in the mirror said, "fire-brigade-trainee-meets-cafeteria-server." The Shedd employee assured me this was standard issue for Shedd trainers."Hello!"I turned and was reassured to see a cheerful young woman dressed exactly like me. It was Lana Vanagasem, whom we would shadow for the next four hours. (The "Trainer for a Day" moniker is a bit of poetic license: The program is actually half a day.)

After introducing herself, Lana described how she nabbed her dream job: a college degree in biology and psychology; an unpaid stint as a Shedd intern, which led to various part-time positions there; and finally, a job as a full-time animal specialist, one step below trainer."It's not just playing with dolphins," she told us of her two years climbing the Shedd ladder. "It's a lot of hard work, also. But it's a lot of fun.

I love it."In no time we had watched a 10-minute video that gave us the basics of marine-mammal training. Not unlike child rearing, training is based on positive reinforcement. Unlike child rearing, however, a whistle and rewards of dead fish are involved.Then we entered the kitchen -- and hit what can only be described as an invisible wall of odoriferous putridity. It was created by squid, pollock, clam and other fishy tidbits -- "all restaurant quality," Lana said -- that were being sorted by a line of trainers and interns to become meals for the Oceanarium's 60-some animals."We go through about 650 pounds of fish a day, maybe more," Lana said.

We could smell every ounce.Our first task was upon us: We rinsed out the stray fish parts from buckets that had been used in a beluga-whale training session. Next we donned rubber gloves and plunged our hands into a box of the half-frozen, clammy, "restaurant-quality" fish, loading the scaly melange into our newly cleansed buckets. Once they were full, we lugged the buckets into a refrigerator, where they sat ready for the next training session.It wasn't quite the transcendent, animal-bonding experience for which I had hoped.

Still, I remained optimistic, following Lana across a gangway toward "Secluded Bay," one of the three areas of the Oceanarium where the animals swim. Under our feet, two dolphins flashed through the blue water."Wow!" Marcella said.As we walked on, two beluga whales popped their heads out of the water. One look at their quirky grins and beseeching eyes and I thought, "These gentle giants are flirting with us!""They're really social," Lana allowed. "They're great about trying to get your attention.

"We watched the end of a beluga whale training session; observed the trainers reviewing the choreography of the ever-popular "Myths and Legends" dolphin show; and waded into the water with long-handle scrub brushes, spending 20 minutes debriding the rocks of algae as the occasional curious dolphin streaked by.During the final hour, Lana instructed us to stand next to trainer Brett Kocanda for the mid-day dolphin presentation. As Enya's "Orinoco Flow" blared from the loudspeakers, dolphins darted back and forth and leapt on cue to the crowd's gasps and applause.

One periodically returned to Brett for a fishy reward.We had learned some hand signals earlier. This was our chance. "OK, 1, 2, 3," Brett prompted. I put my hand straight out, shoulder level, and the dolphin shot out of the water and touched my palm with his nose. Then it rolled on its back at Brett's command."Here, you can feel his heart beat," he said.I placed my palm on the dolphin's white underbelly -- hard, as I'd expected, like rubber.

But the texture of its skin felt strangely silken, as if bathed in luxurious unguents.And as the dolphin's heart beat boldly in my hand -- well, that was, indeed, transcendent.Want to be a trainer for a day?Days: Fridays, Saturdays and Sundays year-round.Times: 8:30 a.m.-12:30 p.m., or 1:30-5:30 p.m.Fee: $350 ($300 members) per person.To register: Call 312-692-3224.