Sluices in the pond walls allowed small fish to enter from the open sea and curtailed the larger fish from egress. The stock was replenished as new fish entered with the high tide. The native Hawaiians built fishponds on Kaua`i, O`ahu, Maui, and Moloka`i, with the most on Moloka`i. The Big Island of Hawai`i had the least due to the abrupt coastline and the few inlets.
Hawaiians also made use of natural fresh or mixed-saltwater ponds, stocking them with fish, using them in the same manner as the man-made. Anchialine ponds filled with brackish water support a type of small, red shrimp (`opae ula). Hawaiians cleaned and maintained the ponds, harvesting the shrimp, and used them as bait for `opelu fishing. They caught and released small ocean fish into other ponds, i.e. manini, aholehole, and moi, which were left to grow to eating size. Caught later in fish traps, the desired fish were collected, and the rest allowed to swim back to the pond. As with all fishing, Hawaiians were guided by the axiom: "Lawa kupono, a`ale `anunu!" (Take only enough for what you need, don't be greedy!)
Fish ponds were stocked with awa (milkfish), `ama`ama, and `anae (two kinds of mullet), `ahole (sea-pig), `opae (shrimp), `o`opu (guppies), and puhi (eels). Other sea fish entering the ponds were ulua, kahala (amberjack), kumu (goatfish), manini (surgeon fish), `o`io (bonefish), and uhu (parrotfish).
This was the first instance of aquaponics and planned sustainability of seafood, in the western Hemisphere.
Dr. Jonathan M. Jackson, 6/17/14