Every year, about 2,000 volunteers across San Francisco pick up trash as a part of the statewide Coastal Cleanup Day. And just about every year, more than half of the volunteers end up at Ocean Beach, where there happens to be less trash to collect.

It was no different Saturday, when more than 1,000 people showed up to the popular beach and the remainder was split among other west side locations and spots on the oft-forgotten eastern side of the city.

Denise McKinney, senior director of service and volunteer resources with the Golden Gate National Parks Conservancy, said the trend has been consistent for the past decade.

“The east side, the bay side, really needs it more,” McKinney said from Ocean Beach Saturday morning. “Generally what happens is we get 75 percent of the volunteers here on the west side, but 75 percent of the trash is picked up on the east side.”

There were 22 cleanup sites across the city, from west side sites like Lands End and Crissy Field maintained by the Golden Gate National Recreation Area, to east side locations like Candlestick Point and India Basin Park under the jurisdiction of the San Francisco Recreation and Park Department.

At India Basin Shoreline Park, San Francisco Baykeeper, a clean water advocate group, led about 50 volunteers in the cleanup effort.

“There’s a lot of trash in the bay that comes here,” Sienna Courter, a Baykeeper staff member, told volunteers. “Our mission is to prevent pollution from happening in the bay.”

Courter stood on top of a picnic table shortly after 9 a.m. as she greeted the crowd and warned them of the danger trash can pose to the bay, nearby wildlife and to humans who eat seafood from the bay. Volunteers were tasked with picking up everything but needles and dead animals.

Baykeeper had expected only 30 people but got a boost in numbers from the Sacred Heart Cathedral girls tennis team. Around 20 junior varsity and varsity members showed up equipped with gloves and buckets as part of an annual team service project, said head coach Amy Kleckner.

The Catholic preparatory school’s motto is, “Enter to Learn, Leave to Serve.”

Team members said they were glad to offer a helping hand, even if it was mandatory.

“It’s nice to help with the environment and feel like you’re giving back,” said Sophie Standen, a 17-year-old senior. “Especially because the sport is outside.”

As volunteers filled black bags with trash, they dropped them off at the front of the park to eventually end up in a huge dumpster to be picked up by Recology.

Baykeepers staff member Eliet Henderson said cleaners usually find small pieces of trash and plastic, but have run into some interesting relics in the past.

“Sometimes people find crazy stuff. Somebody found an exercise bike someone dumped. One year we found half a bowling ball,” she said. “Weird stuff.”

But the primary target? Cigarette butts.

Last year, San Francisco volunteers picked up about 30,000 discarded butts during the three-hour event, organizers said.

At India Basin, Emilio Siguenza started off by removing small bits of plastic and old napkins with a lightweight pickup tool. Siguenza, 41, said he used to work in maintenance at Baker Beach for the Golden Gate National Recreation Area. But now he’s on his own time.

“I got paid to do this. It’s a lot better being paid to do this,” he joked.

With a constant push for more east side volunteers, India Basin fared pretty well. Organizers had about 50 people but said the park has received as few as 15 and as many as 60 volunteers in the past.

“Ocean Beach definitely has a huge draw for people,” Courter said. “But it’s really nice to be over in the east side.”

Jenna Lyons is a San Francisco Chronicle staff writer. Email: jlyons@sfchronicle.com Twitter: @JennaJourno