Legends of ancient Hawaii tell of waters called Puuloa, which was the home of the beneficent Shark Goddess Kaahupahau. Her sharks were man's protectors against many evil spirits and also against the other "man-eating sharks."
The legends, when first recorded in the 19th Century, refer to Ewa as the first area populated on Oahu by the immigrant Polynesians. One Ewa king, Chief Keaunui, is credited with deepening the entrance of the harbour to 15 feet in about the year 1650. During those years and into the 20th Century numerous fish ponds and fish traps were in the entrance and in the many lochs of that body of water. Most were maintained for royal use only.
As early as 1796 European visitors recorded that those waters produced oysters which were used for food, and that pearls were frequently found in them. The pearls were milk white, spherical, and of exquisite lustre. By 1810 the king had found the trading value of the pearls and kept them under royal control.
In the same year (1810), the river leading into the bay was referred to as Wymumme, and in 1819 as Wy Momi which, translated to English, is Pearl River. (The difference in spelling is that of the person recording the spoken word.) Again in 1836 it was recorded that the small pearl oyster was quite abundant and common on the table. From about that time on, the large area of water at the mouth of the river was called Pearl Harbour.
For generations the land surrounding Pearl Harbour was subject to natural erosion and the attrition of "civilization" which allowed much of the harbour to be filled with mud. The oysters could not survive in the mud and were nearly extinct by the late 19th Century.
A visitor from the United States noted in 1840 that there was a depth of 15 feet over the coral bar at the harbour entrance. He suggested to the U.S. Government that they attempt an agreement with the Hawaiian king for the use of the harbour for U.S. ships. This was not acted upon until 1873 and not agreed until 1898. Then the actual work of deepening and widening the channel wasn't started until 1901, at which time a coaling station for the fuelling of ships was erected just inside the entrance. Source.
Pearl Harbor was originally an extensive deep embayment called Wai Nomi (meaning, “pearl water”) or Puʻuloa (meaning, “long hill”) by the Hawaiians. Puʻuloa was regarded as the neighbor of the dolphin god, Kaʻahupahau, and his brother (or father), Kahiʻuka, in Hawaiian legends. According to tradition, Keaunui, the head of the powerful Ewu chiefs, is credited with cutting a navigable channel near the present Puʻuloa saltworks, by which he made the estuary, known as "Pearl Lake," accessible to navigation. Making due allowance for legendary amplification, the estuary already had an outlet for its waters where the present gap is; but Keaunui is typically given the credit for widening and deepening it. Source.
~ Tiffany Thayer, in his Introduction to Charles Fort's Lo!