A show-stopping menagerie

An eerie silence hangs over the huge arena surrounding the million-gallon saltwater tank. An ominous black streak begins to circle slowly beneath the surface. It's big -- too big to go that fast. Water begins to spill over the sides. As the circles tighten and the waves swell, the water suddenly rips with awesome force.

"Ladies and gentlemen," the announcer booms through the loudspeaker, "here's Yaaa-ka-a-a!"

A three-ton killer whale hurls her 15-foot-long body out of the water. Crashing back down, she sends sheets of water six rows deep into the spellbound crowd.

Children squeal with delight. They jump from their seats, dripping wet, laughing and shaking water from their clothing.

Across the lagoon, similar squeals are heard as wide-eyed spectators watch a group of rambunctious chimpanzees swirling red capes and spinning sombreros in a mock bull-fight and Mexican hat dance.

These are but a few of more than 60 attractions that make up Marine World/Africa USA, an entertainment park on the San Francisco Bay, 20 miles south of San Francisco.

The park's Treasure Island is actually four mini-islands, linked by arching Japanese bridges that span a maze of jungle canals. Animals are everywhere, more than 2,000 of them: Zebras, giraffes, and aoudads laze in the sun or take a leisurely stroll around their natural-setting pens. Cub leopards and cheetahs roam all through the park -- accompanied and leashed by their handlers. And camels and elephants even permit the daring visitor to climb on their backs for a mini-safari.

The show park, which opens its 12th season May 21, is a zoo, a circus, a playground, an aquarium, a picnic site, a clinic, and an ecology center -- all in one.

Marine World/Africa USA offers a menagerie of action-packed shows, scheduled at various times throughout each day, which include:

* The killer whale show, starring two orca whales that weigh over two tons each.

* The dolphin show, featuring five of the acrobatic and always-smiling mammals.

* The water ski and boat show -- the only one of its kind west of the Mississippi.

* The wild bird show, where blue-, gold-and scarlet-colored macaws ride a bike on a high wire and shoot off miniature cannons.

* The jungle theater show, with a troupe of chimps, waltzing elephants, and over a dozen lions and Bengal tigers.

Many of the performers in these shows are movie stars of the animal kingdom. Killer whales Yaka and nepo, for example, appeared in the movie Orca, which was filmed largely right at Marine World/Africa USA. Although "Star Wars" was not filmed at the parksite, its producers did borrow the park's four-ton Asian elephant, Mardji, and dressed her up in out-of-this-world garb for a scene in that film. And Shana, the chimpanzee from the television program "Swiss Family Robinson," resides at the facility.

All the animals' performances are polished routines, involving principally natural behavior and worked out by a staff of professional trainers. "Sometimes I wonder, though, who is training whom," says Ron Whitfield, the lion, tiger, and elephant trainer. "The lions have us figured out to a 'T.'"

Training the animals for show, and learning to recognize their behavior patterns so as to anticipate problems, is usually a two-to three-year process. An expensive education, in light of the fact that the park's annual food bill is approximately $325,000.

Yet some of the animals help out in the teaching process. "During one show," says one of the whale trainers, "the female didn't do the right trick. The male went over and vocalized to her. 'You better get it together.' She got in line right away."

The animals are not, however, the only ones performing razor-sharp routines. A Troupe of daredevil water skiers and aqua belles whiz around an 1,800-foot lagoon at 30 miles an hour, skiing barefoot, flying off a five-foot jump ramp and engineering a 360-degree circle before hitting the water, or forming a three-tiered, nine-person pyramid on skis. This water ski and boat show is one of the biggest crowd-getters at the park.

Pure entertainment is not the primary raison d'etre of Marine World/Africa USA. Tha park is an educational facility, and spectators often become students, learning from "hands on" experience about the size, feel, looks, and habits of some 50 species of animals. These animals either roam the park with a handler, or are in special cages, pens, or pools easily accessible to the inquisitive.

To learn even more about the animals in the park, visitors may attend short talks given regularly at the outdoor Ecology Theater. Here handlers discuss the importance of wildlife conservation, exhibit an endangered species, and explain the park's affection-based animal training process -- a training theory that involves bottle-feeding young animals and disciplining them with love rather than whips.

As part of its active effort to protect and preserve all forms of wildlife, Marine World/Africa USA maintains an extremely successful breeding program in cooperation with zoos and aquariums worldwide. The park has become the world's largest breeder of, believe it or not, ostriches. Last year one of Marine World's tigers gave birth to eight cubs, said to be the largest number ever born in captivity.

A nonprofit research foundation exists at the facility. Among the foundation's current investigations is a study of the correlation between earthquake prediction and animal behavior.

Marine World extends its services not only to other animal compounds and research teams, but to the Bay Area community at large -- particulartly schools. Special admission discounts are available for schools and special-interest groups. The park will arrange a previsit assembly at a school, complete with films, talks by trainers, and even a guest appearance by one of the park animals. So far this year, such assemblies have introduced more than 40,000 schoolchildren in northern California to Marine World animals.

Educational programs at the park can also be scheduled the day a school group visits.

With its variety of performances and resources, Marine World/Africa USA attracts thousands of visitors each week during its spring and summer season. The entire facility may also be rented for private parties, with catering and entertainment available. The park is open seven days a week between June and September, from 9:30 a.m. to 5:30 p.m., and from Wednesday through Sunday in April, May, and October. Admission is $7.95 for adults, $4.95 children aged 5- 12, and free for children under 5. Group rates are available for groups of 15 or more.