"I'm so irate," said Peter Rappa, a Hawai'i Kai resident and Hawai'i Sea Grant College marine science faculty member in charge of the education program at the bay. "I understand why the gate was put up, but not about not going to the community for input."

Rappa, who rides his bicycle to the bay, usually cuts through the park to get to Kalaniana'ole Highway and was surprised when the gate was erected last week. He had to climb over it with his bicycle to get through. Motorists caught unawares by the gate have to reverse down the steep one-lane road, which isn't wide enough for a car to turn around on.

Though a sign at the park notes that parking for Hanauma Bay is not allowed, taxi drivers, who have unlimited access to the bay, were shuttling visitors to the nature preserve, said Bill Balfour, city Department of Parks and Recreation director. The new gate at the Kalaniana'ole Highway entrance to the park was installed to stop that practice, he said.

"The only (other) way to do something was to put police officers there," Balfour said. "It's not a thoroughfare. We're not inconveniencing anyone."

The bay limits the number of visitors who come in by car but does not limit the number of visitors coming in via taxi, Balfour said.

Though the bay's staff did not ask for the gate, keeping people from coming to the nature preserve when it's at capacity is important to protect the bay, said John Norris, president of the Friends of Hanauma Bay.

"Allowing people to park at the district park erodes our control over the number of visitors to the bay," Norris said.

Roughly 4,000 people come to the bay daily. They come by car, by taxi, by tour bus or snorkel company.

About a decade ago the city launched efforts to limit the number of people using Hanauma Bay, citing the need to protect the bay's ecosystem. Measures to limit the number of people ranged from the parking to closing one day a week and building a $13 million education center where people must view a safety and educational video before proceeding to the water.

Still, Rappa said, the gate keeps motorists from having easy access from the highway to the park and limits walkers, runners and bicyclists' ability to recreate.

Mary Houghton, Hawai'i Kai Neighborhood Board parks committee chairwoman, said there was always talk of a gate at that park entrance because of safety concerns from the rifle range.