Waikalua Loko Ia Renewable Energy Final Report

Abstract

Many loko i‘a (fishponds) across Hawai‘i face degraded coastal ecosystems, and destruction of nursery habitats which have disrupted their capacity for fish recruitment and pond productivity. Growing anthropogenic effects such as urbanization, channelization and residential and economic development have disrupted natural loko i‘a systems, resulting in kiaʻi loko (fishpond caretakers) observing a five year decline in suboptimal stocking density (estimated to be 2,000+ pua per acre per year) (Conservation International Hawaiʻi Program, Center for Oceans Report, 2020). With natural stocking of fish becoming more difficult, many loko i‘a are attempting to fill this critical gap by developing efficient and economically viable onsite holding and grow out facilities for targeted commercial and subsistence marine species. To limit operation cost and reduce environmental impacts, multi-trophic aquaculture incorporates the production and waste of cultivated native species of fish, limu, sea cucumbers, and bivalves where the waste products of one species serves as a nutrient source for another. Specifically at Waikalua Aquatic Institute however, these robust acclimation centers for rearing juveniles require multiple rounds of filtration to incorporate water sourced from the nearby loko i'a, resulting in high energy demands and reduction in system efficiency and economic viability. Operational costs associated with high energy filtration systems of these aquaculture systems must be addressed to reduce high electric costs and still be able to sustainably support local food security and indigenous sovereignty.