Aquasend, an aquaculture sensor startup, recently deployed three Aquasend beacons at Waikalua Loko l’a, a Hawaiian fish lake, through a partnership in the Xylem Innovation Labs Incubator Program. The Pacific American Foundation, which oversees the project, uses the beacon data to help conserve native mullet and milkfish.
Prior to Hawaii’s statehood, there were approximately 500 fishponds throughout the Hawaiian Islands. Over time, the number of fish ponds decreased to less than 100. Efforts to protect Hawaii’s remaining fishponds are growing with help from the Pacific American Foundation. They focus on restoring and studying the carrying capacity of Waikalua Loko l’a. To aid in these efforts, Aquasend Beacons will monitor the amount of biomass the pond is equipped to support through dissolved oxygen (DO) levels and temperature data collected.
Located in Oahu, Hawaii, the Waikalua Loko l’a Fishpond was built over 400 years ago by the first Hawaiians after a careful study of water and tides. The fisherman realized that creating water barriers would lead to a more consistent and abundant harvest of fish.
Waikalua Loko l’a works with stationary gates, called makahas, located in the channel and built into the seaward wall of the pond. Keeping with the original design created by Hawaiian ancestors, the gates were made with small upright wooden poles connected by rope to release small fish into the pond. The fish would feed, grow, and become trapped in the pond due to their larger size.
The pond is made of a combination of salt and fresh water, the Waikalua Loko l’a consists of North Pacific salt water from a bay that actively circulates the pond, filtering through the land to enter the pond, while the saltwater, freshwater streams surround the Kawa and Kane’ohe . pond.
The Aquasend Beacon will continuously monitor the pond’s dissolved oxygen (DO) and temperature levels throughout the day to assess the pond’s fish density. It has been more than 50 years since Waikalua Loko l’a Pond became acclimated to aquatic life, so it is essential that pond water is carefully monitored and brought to a safe level for successful pond restoration.
“We are excited to be a part of the regrowth of Waikalua Loko l’a Pond and have the opportunity to expand Aquasend water technology operations through our partnership in Xylem’s Incubator Program. Our goal is to support this industry with information and solutions,” says Kristin Elliott, CEO of Aquasend.
Advanced water quality technology is needed to determine pond viability. Three Aquasend beacons are positioned and installed across the pond’s saltwater to collect data on both moving and still water points. The buoys collect dissolved oxygen and temperature measurements continuously every day for three months in real time.
The data gathered over these months will give the Pacific American Foundation the basic information it needs to begin safely populating the pond with native mullet and milkfish. Beacon’s research will provide a better understanding of Waikalua Loko l’a conditions and ultimately help grow Waikalua Loko l’a and other ponds across the Hawaiian Islands to generate income and sell local produce.