South Bay’s biggest nature preserve prepares for Easter picnickers.

Harbor Regional Park, the largest inland recreational area in the South Bay, expects to receive its share of Easter weekenders looking for a few hours of outdoor relaxation.

The 231-acre park in Harbor City surrounds a large freshwater lake and offers the usual park attractions, but on a larger scale: picnic grounds, children’s playgrounds, fishing, bike paths, a nine-hole golf course and lots of opportunity to observe the plants, birds, lizards and other living things that make their home there.

For bird watchers, the park has several towers for a better view. It has a campground for organized groups such as the Boy Scouts and Girl Scouts, and a swimming pool that opens in June. Park workers say fishing enthusiasts catch carp and catfish in the lake but can’t eat them because the water--though clean-looking--is polluted.

Physical fitness buffs interested in improving their muscular and cardiovascular functions can use the 18-station exercise course donated to the park in 1985 by the nearby Kaiser Permanente Medical Center. Each station has a heart-check device to measure pulses and help ensure that the exercise is proceeding at the right pace.

Visitors with an interest in history may also imagine the ghostly presence of the Indians who lived there centuries ago in two large villages called Saungna and Masaunga--both meaning “place of many rushes.” Historians say the lake, once called Bixby Slough, extended northeast over a wider area and was surrounded by willows, bulrushes, milk thistles and other grasslike vegetation.

Today, Harbor Regional is part of the Pacific Flyway and provides resting, feeding and nesting areas for many migratory and resident birds. All birds, plants and animals are protected under wildlife sanctuary laws.

Los Angeles acquired Bixby Slough in 1953 and renamed the area in 1971. The park’s new host is Jeff Costa, a city Parks and Recreation Department employee who took over management of Harbor Regional in October. Howard Snelson, one of five park workers, said the new boss is a trouble-shooter sent to upgrade the facility, which has been deteriorating in recent years.

“That’s my challenge,” said Costa, who has had to car-pool from his home in distant Diamond Bar since getting his new assignment. “Harbor Regional has always been one of the most beautiful places around, but we can make it better.”

Costa, who stresses the park’s family orientation, said his crew has been busy sprucing up for the Easter weekend crowd. After that, he plans to continue planting flower gardens, trimming brush, improving paths and generally enhancing the area. He said he hopes to get at least one gazebo built to attract wedding parties, and canoes may be permitted back on the lake later this year.

Canoeing, sailing and pedal-boating gradually vanished from the lake years ago, although canoes are still brought out for special occasions.

Costa said his crew’s biggest daily job is “just keeping the place clean and nice-looking.” That means mainly cleaning off the graffiti that show up periodically in the public restrooms and picking up a lot of litter, in addition to maintaining all the faucets, irrigation lines, wiring, door handles and other things that keep breaking down.

Taking a balanced view of the public’s cooperation, Costa said: “Half of the people are really good about using the trash barrels and not leaving a mess behind them. The other half, well. . . .”

He hopes Easter weekenders will take heed and join the first half.