Research Projects 2022-2024

Exploring nutrient utilization in native Hawaiian seaweeds for parallel aquaculture development across restoration and sustainability applications

PRINCIPAL INVESTIGATOR: Craig Nelson
Sea Grant Graduate Fellow: Sean Swift
Research Track: Aquaculture

Green seaweed grows through netting spread across a PVC frame
Limu production is a growing industry in Hawaiian aquaculture, with many types of native limu being grown. (Photo: Keeler Martin)

The primary nutrient source for limu aquaculture by Ocean Era, LLC, an industry partner, is deep ocean water retrieved from 3,000 ft using a specialized pumping system. Future aquaculture efforts need alternative and sustainable nutrient sources. This project seeks to advance aquaculture of edible native limu (seaweeds or macroalgae) in the Hawaiian Archipelago, supporting a graduate student to work closely with Ocean Era in Kailua-Kona, Hawaiʻi, on many ongoing seaweed aquaculture projects.

This project will evaluate the potential for using nutrient-rich groundwater or fish aquaculture effluent as nutrient sources for limu aquaculture. We hypothesize that both of these potential nutrient sources can be diluted and used to support large-scale, sustainable limu aquaculture throughout the state of Hawaiʻi. We will evaluate nutrient use efficiency (growth per unit nutrient enrichment) by three species of edible limu supplied the three different nutrient sources. We will also evaluate whether these alternative nutrient sources have negative impacts on the microbiota associated with limu, with a particular eye toward assuring safety and quality of edible market products.