Employing traditional practices to protect coastal infrastructure and enhance nearshore fisheries in Hawaiʻi

Research Projects 2026-2028

Employing traditional practices to protect coastal infrastructure and enhance nearshore fisheries in Hawaiʻi

A pile of algae-covered rocks sit in clear shallow waters, with black-striped yellow fish swimming around them — This imu/umu kai (traditional Hawaiian fish house) was constructed in the nearshore zone of Hāʻena, Kaua‘i. These stone structures are designed to mimic natural reef features, providing shelter and recruitment habitat for juvenile reef fish such as Manini, shown here utilizing the structure.

PRINCIPAL INVESTIGATOR: Robert Toonen
Graduate fellow: ʻAʻaliʻi Kelling
Research Track: Island Sustainability and Resilience

Coral reef ecosystems globally, including in Hawaiʻi, are facing profound degradation from multiple, interacting stressors, resulting in severe losses of coral cover, fish biomass, and coastal protection. This decline not only threatens ecological health but undermines local food security. An essential but often overlooked Indigenous management strategy is the imu/umu kai— Hawaiian rock structures that serve as “fish houses” to aggregate resource species and provide vital habitat. This project will thoroughly document these traditional imu practices through oral history and archival analysis, integrating this Indigenous knowledge with conventional fish- habitat research. By combining cultural principles with quantitative surveys and advanced imaging, the study will co-design and field-test two types of imu-inspired artificial reefs on degraded Oʻahu sites. The goal is to generate a scalable model for hybrid reef restoration that simultaneously maximizes fish species richness and the abundance of key resource species. Ultimately, this research provides a culturally grounded, empirically tested strategy to bolster nearshore fisheries management and increase coastal resilience across the Pacific.