Claim: In the Ancient Hawaiian aquaculture, fishponds were located next to the mouth of a stream and had porous lava walls that let in seawater (or sometimes fresh or brackish water, as in the case of the "Menehune" fishpond near Līhuʻe, Kauaʻi), but prevent the fish from escaping.
Evidence: The porous lava walls let in seawater (or sometimes fresh or brackish water, as in the case of the "Menehune" fishpond near LÄ«huÊ»e, KauaÊ»i), but prevent the fish from escaping. Fishponds were located next to the mouth of a stream, so by opening a sluice gate the pondkeeper provided the fish with water rich in nutrients that had passed through inland, terraced pondfields and returned to the stream.