I spent a weekend recently at the Fairmont Orchid at the Mauna Lani Resort, and learned that the Kalahuipua'a Fishponds are the spiritual center of the area. Predating even the earliest Western contact, the ponds are from the days when the land and sea supported the Hawaiian Ali'i (royalty) -- the original inhabitants of the land.
The first true fishponds were probably built during the latter half of the fifteenth century. And increasingly thereafter as chiefs could command the labor necessary to transport the tons of rock and coral used in the enclosing walls. These ponds, which yielded several hundred pounds of fish per acre annually, were not only feats of engineering technology, but reflected chiefly power and were a major symbol of the intensification of agricultural and aquacultural production. nps.gov
The Hawaiian people practiced the most advanced fish husbandry among the original peoples of the Pacific. Fishponds (Hawaiian: loko I’a) were typically shallow areas of a reef flat surrounded by a low lava rock wall built out from the shore. Several species of edible fish such as mullet thrived in such ponds, and methods were developed to make them easy to catch. The Hawaiian fishpond was primarily a grazing area in which the fishpond keeper cultivated algae; much in the way a cattle rancher cultivates grass for his cattle. Ponds were fed with cut grass, mussels, clams, seaweeds, and taro leaves. The porous lava walls let in seawater or sometimes fresh or brackish water but prevented the fish from escaping. servinghistory.com
The ancient Hawaiians and their vast system of fish ponds are one of the foremost examples of successful fish farming in the world. Royal fishponds and ancient walled fish traps were part of the everyday landscape of old Hawaii. When Captain James Cook reached Hawaii in 1778, there were approximately 360 fishponds producing almost two million pounds of fish per year. uhh.hawaii
The coastal fishponds and their resources were the exclusive property of the district chief and were not a major economic resource to the general population, who were prohibited by kapu from fishing, collecting seaweed, or polluting the pond.
Commoners, especially women, were seldom in the vicinity of royal fishponds. There was little advantage for commoners to live near a pond for fear of breaking the kapu. (Kapu means forbidden, though it also carries the meanings of sacred, consecrated, or holy. In ancient Hawaii, kapu refers to the ancient system of laws and regulations. An offense that was kapu was often a corporal offense, but also often denoted a threat to spiritual power, or theft of “mana.” Kapus were strictly enforced. Breaking one, even unintentionally, often meant immediate death.) Possibly after abandonment of the kapu system in the early nineteenth century did the population concentrate more around these ponds because the resources became available to them. www.nps.gov
By 1985 only seven ponds remained in use. It is estimated that the yields from the Hawaiian fishpond systems operating before the arrival of the Europeans would be on par with most contemporary extensive aquaculture systems; yet the traditional Hawaiian fishponds did not receive fertilization from animal or human wastes of any kind. http://cmbc.ucsd.edu/Research/student_research/fishponds/
I have no idea how many fish ponds are in use today. I did see notice of a recent study, supported by the National Science Foundation of a project at Scripps Institution of Oceanography, Center for Marine Biodiversity and Conservation, whose goals were “to improve upon current techniques and management practices for marine aquaculture, through a detailed study of historical techniques that were used successfully throughout the Hawaiian Islands.” http://cmbc.ucsd.edu/Research/student_research/fishponds/
With the world's fish populations dwindling at an alarming rate, interest in aquaculture is on the rise. From the ancient loko iʻa to the advanced aquaculture research facilities at UH Hilo, Hawaii has a long tradition of innovation in this field. The reemergence of the use of fish ponds may one day be an important source of ecologically sound and sustainable fish production and an important export business for the people and state of Hawaii.