Before a ban on fish-feeding at Hanauma Bay took effect in 1999, a half-ton of bread was being dumped in the marine preserve's waters every day by snorkelers hoping to whip up a feeding frenzy.

"There was just a tremendous amount of fish that would swim right up to your feet for a handout. Everything and anything went into the bay — peas, cheese, bread, snack food," recalls Larry Winnik, 64, who has been snorkeling at Hanauma for more than 20 years.

By early afternoon, the ocean surface glistened with an oily sheen of food fat and suntan lotion.

Ten years later, "the bay has reverted back to its natural balance of fish," according to Winnik, former president of the Friends of Hanauma Bay.

Other regulations enacted by the city drastically cut the number of visitors and commercial operators at the popular preserve, and officials say the benefits of a mandatory briefing on reef etiquette and conservation for first-time Hanauma visitors reach well beyond the nature preserve's boundaries. The state Division of Aquatic Resources estimates the education program saves 10.5 acres of reef from damage every year.

"If we can get a little bit of that appreciation and stewardship into each of our visitors who come to Hanauma, they can learn to reduce their environmental footprint and take that message when they are hiking on trails or going off to Waikiki or going to Maui," said Elizabeth Kumabe, University of Hawai'i Sea Grant extension agent and Education Program leader at Hanauma.

Hanauma Bay was largely neglected until an influx of tourists began overwhelming the preserve in the 1980s, when 10,000 to 12,000 people jammed the site each day.

"There was overcrowding of people on the beach, overcrowding of vehicles in the park and on the highway and trampling of the reef," said Robin Bond, a retired Department of Parks and Recreation official who helped develop a 1990 management plan for the preserve.

"The biggest thing was to get on the reef and walk out to the edge and look in holes for fish. There was so much trampling of the reef. It was unabated," he said.

Inside the reef, in the most crowded snorkeling areas, there were little or no live corals and fish weren't behaving naturally, said Bond, 67.

"Nenue normally like to hide and swim in caves. The nenue were swimming to shore and taking food out of people's hands and biting them," he said.

When the fish-feeding ban was implemented, large numbers of nenue (chubs or rudderfish) and 'ama'ama (mullet) attracted by the human handouts left the bay, and order was restored to the marine ecosystem.

Alton Miyasaka, an aquatic biologist with the state Division of Aquatic Resources, said snorkelers may be disappointed there are fewer fish .

"In terms of what is a sustainable natural environment, it's better today than it was 20 years ago," he said.

Most commercial activities are now banned at Hanauma, access to the lower bay is limited to 2,000 people at any one time, and when the parking lot is filled, cars are turned away. The city began charging admission and parking fees in 1998, and the preserve is closed one day a week. Improvements were made to the upper and lower bay facilities, and a $16.2 million Marine Education Center opened in 2002.

About 3,000 to 4,000 people now visit Hanauma Bay Nature Preserve per day. In the past fiscal year, 780,000 people went to the lower beach while 500,000 visited just the upper bay, according to the Department of Parks and Recreation.

The reefs are showing signs of regenerating along the sides of the bay, and more than 200 varieties of marine animals have been observed in its clear waters. City Parks Director Lester Chang said the management program can be judged a success for the sole reason "it stopped any further damage."