If the eight Channel Islands dotting the California coast were siblings, then Santa Catalina would be the wildly popular and conventionally pretty one, eliciting no small amount of Jan Brady-type envy from the others.

Catalina would be the fun-living extrovert always asked out on dates, always being doted on by the rich and glamorous, sought out by those looking for a good time. Yet, it also would be dismissed as somewhat shallow and less substantial than its sister islands to the north, the ones under National Park protection, the ones that, if personified, would wear fleece and hiking boots, not halter tops and heels.

And, according to a just-released beach report card by the Natural Resources Defense Council, you might pick up a bacterial infection from Catalina. Avalon beach, near the iconic pier, overwhelmingly tops the list of California’s “dirtiest” beaches, with 83 percent of water samples exceeding state pollution standards.

Yet to dismiss Catalina as merely “a poor man’s Hawaii,” lacking in biogeographic gravitas (and environmental stewardship, at least at the beach) because it is privately owned and home to hotels, boutiques and restaurants with cuisine ranging from $45 lobster to $2.50 corn dogs, would be a mistake.

Only 12 percent of the island — essentially the community of Avalon (pop. 4,000), celebrating its 100th birthday this summer — is developed. The other 88 percent, roughly 50 miles of coastline and 42,000 acres, was deeded in 1972 to the Catalina Island Conservancy from chewing gum magnate P.K. Wrigley and remains wild, if not pristine.

What you must do when visiting Catalina is embrace the contradictions.

Whereas other Channel Islands have been almost militaristic in their vigilance about eradicating invasive species, Catalina still allows 150 to 200 bison to roam the hillsides. The bison, frankly, are as much an attraction — not to mention a tradition — as parasailing, ziplining or licking soft ice cream cones.

Yet the conservancy has culled the pernicious wild boar and goats from the hillsides, clearing the way for the island foxes to once more roam free.

Whereas other islands draw scant visitors even during spring and summer months, Catalina’s population swells to more than twice its size on sunny weekends, ferry after ferry depositing cooler-carrying, inner-tube-toting mainlanders clogging its streets with rental golf carts.

Yet the city and the conservancy have worked together to keep the bulk of the island from being negatively impacted by the teeming touristic horde, Avalon beach’s problems notwithstanding. Jeep tours are allowed into the “backcountry” where the bison roam, but they are tightly regulated and limited to wide fire roads. A recently completed 37-mile, mostly single-track Trans-Catalina Trail encourages foot traffic deep into the interior.

And whereas the gripping entertainment on, say, Anacapa Island to the north is to watch the western gull chicks hatch, on Catalina the 12- story casino building has a first-run movie theater showing “Fast and Furious 6.” And whereas you might be able to forage for berries on Santa Cruz Island, Catalina conveniently has a Vons.

You can, however, have a pleasant weekend stay on Catalina without guilty thoughts that you are further endangering an ecosystem. The Catalina Island Conservancy has your back — at least 88 percent of it.

“It’s an incredible balancing act,” said Rosie Taylor, a conservancy visitor services specialist. “Part of our charter actually states we are stewards of the land conserving Catalina through a balance of conservation, recreation and education. The city itself helps by restricting the number of vehicles on the island.

“And, except for the jeep tours, the only way to get into the interior is hiking or biking. On our (jeep) tours, we have naturalists that try to educate the (tourists). We think it’s a good thing that people can get out there and see what we’re trying to preserve.”

Cesar Ocampo, a conservancy naturalist who leads a tour, said there’s no question what tourists want to see.

“The bison,” he said. “People are blown away to see a bison on an island. But we also have endemic species out there like foxes and squirrels. We’ve got some plants found here and nowhere else in the world. We’ll stop at an eagle aviary, and you can see the beaches on the (island’s) backside, which are really great. We have old military bunkers from World War II still out there.”

But the bison are the star attractions. They were brought here in the 1920s by a movie production company and, apparently, liked it so much they never left. Sometimes, as are stars’ wont, they make themselves scarce for tourists.

“We try to tell people from the beginning that we don’t have the bison on a schedule.”

No zoo, this.

If you want a sure thing when it comes to the natural world on Catalina, you can sign up for fish-friendly glass-bottom boat or “semi-submersible” submarine tours, the latter of which allows you to push a button (for an extra charge) and send “torpedoes” of fish food at the orange garibaldi and local species roaming the waters.

On shore, a sense of history can be found at the Wrigley Memorial and Botanical Garden, where the first family of the island entertained the rich or famous (and sometimes both rich and famous) while the Wrigley-owned Chicago Cubs tossed around baseballs at an informal spring training.

These days, of course, the ball players head to Arizona in the spring, and the movie stars mostly stay away. Yet stars of yesteryear remain in the small but memento-filled Catalina Island Museum, founded in 1953.

At one time, the likes of Frank Sinatra, John Wayne and Marilyn Monroe graced Avalon’s boardwalk. The museum, in something of a macabre gesture, reserved a wing of the museum for the mysterious drowning death of actress Natalie Wood off Catalina in 1981.

Old West novelist Zane Grey, a longtime Catalina resident, lives on in the form of a hotel named after him. Actually, the well-appointed adobe villa overlooking Casino Point is Grey’s former home. Because it’s away from the hubbub of downtown Avalon, the Zane Grey Pueblo Hotel doesn’t get the clientele of the fancier digs such as Pavilion.

“You can get 10,000 people in town, but up here you can’t even feel it,” said Michael Shehabi, the hotel’s general manager. “The owners purposely put in no phones and no TVs. We take pride in not having any of those things. We preach about how relative the quiet is. Quietness is a virtue at our hotel. Zane Grey felt Catalina was a place to come to to forget about this crazy world of ours.”

Apparently, quiet isn’t important to most who visit Catalina, because the Grey hotel is for sale for $6.5 million (“2 million down, the sellers carry back a note,” Shehabi said).

Most people like the action going on in town in “legendary” bars such as Luau Larry’s and El Galleon and upscale restaurants such as the Avalon Grille and the just-opened Bluewater Avalon.

Wayne Griffin, president and CEO of the Avalon Chamber of Commerce, says the city has bounced back from recessionary times and now embraces a mix of upscale dining and relatively affordable family options.

After the mid-2000 slump, Griffin said Avalon needed to update its image — add “new product development,” as he calls it.

Development is a term freighted with baggage, especially in an area with finite space, but the Santa Catalina Co., run by heirs of the Wrigleys, took existing land and reimagined it into a resort within a resort, Griffin said.

“We can absolutely trace our financial turnaround to the date the zip line opened — April of 2010,” Griffin said. “That investment gave us something to talk about from a marketing standpoint. We know people came to the island just to ride the zip line. It was sold out the first nine months it was open, and it continues to be a big draw.”

The zip line ($125) is part thrill ride, part eco-tour. You start in the hills above town off of Stage Road, and follow five consecutive zip lines about three-quarters of a mile down Descanso Canyon to the beach. Along the way, you’ll pause briefly between lines at “eco-stations” to get a naturalist’s take on the flora and fauna before you zip off once more.

Teenager Mike Cratch, waiting in line for his turn, said he came from Simi Valley in Ventura County for the ride.

“That’s all I’ve heard about this place,” he said. “That’s all my friends talk about: Go to Catalina, ride the zip line.”

But to Jessica Washburn, also waiting in line, Catalina is more than just a new adrenaline-pumping thrill ride.

“Ziplining is trendy and everything,” she said, “but the magical thing about Catalina is that it’s got attractions for everybody.”

It doesn’t take hurtling across a canyon to get Lenna McClennen excited about Catalina. She’s a regular from Orange County.

“What’s not to like?” said McClennen, 55. “It’s just a hop, skip and a jump away for people who can’t afford Hawaii. I’m just going for the day. I’ll take the last ferry back. I’ve been coming since I was 22 years old, and it never gets old. I always have fun.”

To some, the attraction is no attraction at all.

Many people come to Catalina to just dig their toes in the sand. Take Jim and Joan Nielsen of San Clemente. They were the first two people out on the sandy shores of South Beach one morning in matching lawn chairs.

Joan was reading Julian Barnes’ latest novel; Jim had a magazine across his chest and his eyes closed.

“This is our first time back here in 25 years,” Jim said. “It hasn’t changed much, maybe more golf carts. But the whole point here is getting away from ordinary life.”

(c)2013 The Sacramento Bee (Sacramento, Calif.). Distributed by MCT Information Services.

Photo Credit: Avalon Bay is the most populous area on Catalina Island. Aaron Logan / Flickr