Huilua Fishpond

Huilua Fishpond, in Ahupuaʻa O Kahana State Park on windward Oʻahu, is one of the few surviving ancient Hawaiian fishponds that were still operational well into the 20th century. It was declared a U.S. National Historic Landmark in 1962, shortly after it had been severely damaged by the 1960 tsunami. It was added to the National Register of Historic Places on L: December 29, 1962.

The fishpond may have started as a sandbar where ocean currents met the stream mouth. A 500-foot (150 m) permeable rock seawall (called kuapā in Hawaiian) was added along the shoreline to enclose about 7 acres (28,000 m²) of fertile brackish water. The wall was about 4 feet (1.2 m) wide and stood about 4 feet (1.2 m) above high tide, with two lashed-pole gates (called mākāhā) that allowed little fish in but kept bigger fish from escaping. The name Huilua, which can be translated 'join-twice', may refer to the two gates. The favorite type of fish in the pond were ʻamaʻama (mullet), which reproduce in the ocean but can live in either fresh, brackish, or salt water.

Many Hawaiian fishponds were built about 400 to 600 years ago. They were especially numerous in large expanses of shallow sea, such as Kāneʻohe Bay and Pearl Harbor. Each fishpond had a pondkeeper (kiaʻi loko) who lived nearby and oversaw its maintenance. Sam Pua Haʻaheo was the pondkeeper for Huilua from 1924, just after the 1923 tsunami, until 1946, when another tsunami hit. The fishpond suffered further tsunami damage in 1957 and 1960. The most recent restoration work began in 1993 as a cooperative project between the State Park service and Friends of Kahana, an organization of local residents.