Understanding Change: Examining the Effect of Ahupua‘a Restoration Efforts on Water Circulation in Loko I‘a O He‘eia, a Native Hawaiian Fishpond

Abstract

He‘eia National Estuarine Research Reserve (NERR), established as the 29th NERR in the U.S. national system in 2017, provides a living laboratory to better understand the complex relationships in areas where freshwater streams meet the sea. He‘eia Fishpond, located within He‘eia NERR boundaries, is an 88-acre, approximately 800-year old traditional Native Hawaiian fishpond that once provided sustenance for the communities in the area. However, a century of land-use change and introduction of non- native species have resulted in low productivity of food fish in He‘eia Fishpond. One of He‘eia NERR’s missions include removing invasive species to restore the watershed to a system that reflects Indigenous knowledge and practices. In keeping with this mission, this project aimed to understand habitat change by measuring water circulation and flow related to invasive species removal efforts at He‘eia Fishpond. Efforts to restore the fishpond into a system that produces native food fish species for community sustenance is currently ongoing, led by a Native Hawaiian community non-profit group, Paepae o He‘eia, also the caretakers of He‘eia Fishpond. Water flux was measured at each of the six sluice gates (mākāhā), relative flow was measured within the fishpond, and the data was compared to water circulation data from a similar study conducted in the pond in 2018. As estuarine environments are highly dynamic in nature, understanding how the removal of invasive algae affects water circulation throughout the fishpond since 2018 may aid in addressing future coastal management issues and restoration actions for resource managers within the He‘eia NERR.