Aquaculture and Water Resource Management in Native Hawaii

by Luke Carothers

The collection of islands that now make up the state of Hawaii have been inhabited by humans for the better part of the last two millennia. The first to arrive did so in wooden canoes that carried themselves, plants for cultivation, and livestock. These first inhabitants found few edible plants that were native to the islands, and began to cultivate the plants they brought with them. To support this cultivation, inhabitants began to construct irrigation ditches that carried water from the numerous freshwater streams to areas growing crops such as taro, bananas, breadfruit, sugar cane, sweet potatoes, and yams.

The islands’ streams played a particularly important role in their population growth. The fresh, cool water would flow through the irrigation ditches and provide nourishment to the growing crops before flowing back into the stream. These ditches would eventually be enhanced by the construction of dams, which would often be torn down and moved as the need arose. Over time, they cultivated the soil of mountain slopes and valley bottoms—supporting these projects with stone walls to stop erosion. These irrigation systems became part of a much larger network of water infrastructure that supported a burgeoning population.

In addition to having an unparalleled understanding of boat building and crop irrigation, Polynesian inhabitants of the islands also developed a strong tradition of aquaculture. Beginning around 1200 CE, Hawaiians started using lava rocks and packed earth to construct fish ponds that vastly increased the amount of food the islands could produce. Starting from the shoreline, fishponds were ringed by low walls of porous lava rock which allowed water to flow through without enough space for the fish to escape. The locations of these fishponds made them extremely fertile places to create thriving fish farms. These fishponds again benefitted from the cool freshwater streams. Located near the mouths of these streams, Hawaiian fishponds of this time were constructed to benefit from inland irrigation as the nutrient-rich water that resulted flooded the fishponds, supporting a massive number of fish. In the five centuries between the development of aquaculture and the first European contact, native Hawaiians constructed over 350 of these fishponds that produced over 2 million pounds of fish annually.

The nutrient-rich fresh water that provided sustenance for the enclosed fish was part of a much larger network of water-based infrastructure that supported sustained population growth throughout the time prior to European contact. Surrounded by saltwater, the native Hawaiians placed a strict emphasis on the management and maintenance of their freshwater resources. Shallow wells, springs, and streams provided the islands’ inhabitants with fresh drinking water. By creating a system that incorporated upland agriculture, fishing, aquaculture, and gardening, these early Hawaiians shifted to a society that focused more on the land than on the sea. The ability to tap into rich terrestrial and marine resources meant that, long before European contact, Hawaiians had established a sophisticated system of land-use agreements that facilitated the open trade of goods not only within the individual islands but rather between the islands. Thanks to their ability to navigate the seas effectively, trade thrived between the Hawaiian islands, and a thriving economy emerged. This resulted in residents having access to a wide variety of goods and resources, supporting further development and growth.

From this effective utilization of resources, Hawaiians began to specialize in various crafts and trades, which varied depending on the resources on the individual islands. The island of O’ahu, for example, specialized in producing a bark fabric known as kapa. This intricately designed fabric was created by beating tree bark until it became soft and dye-stamping it to create geometric patterns. Similarly, the island of Maui grew to specialize as the primary manufacturer of canoes.

Although surrounded by the vastness of the Pacific Ocean’s salty waters, the Hawaiian islands had developed a system that could not only support a significant human population but rather a thriving and diverse culture and specialized economy. This was done by effectively managing water resources with a flexible and cooperative approach, which allowed populations to shift and efficiently manage the flow of water and resources throughout needed areas.