Limu (native macroalgae) plays a critical role in Hawaiʻi’s nearshore ecosystems, acting as a natural biofilter, providing habitat and sustenance for marine life, and serving as a valuable resource for human consumption while holding deep cultural significance. However, the decline of native limu species due to environmental threats and human impacts has underscored the need for ongoing restoration efforts. Furthermore, little is documented about the specific conditions native limu require to thrive in cultivation systems that support broader restoration efforts. This study aims to determine the optimal growth conditions for Limu Manauea Loloa (Gracilaria parvispora) to support restoration and sustainable aquaculture.
In addition, the study includes a Hawaiʻi invasive species, Gracilaria salicornia, to compare growth responses across a nutrient availability gradient, helping to understand competitive dynamics and environmental thresholds influencing both species. The study evaluates key environmental factors influencing limu growth by replicating salinity and nutrient levels found at sites with varying cultivation success, such as loko iʻa and restorative aquaculture facilities. It assesses how these conditions affect biomass production and photosynthetic efficiency in Limu Manauea Loloa and G. salicornia. Findings will inform restoration strategies aligned with ecological and cultural priorities, fostering sustainable limu stewardship.
Loko iʻa, traditional Hawaiian fishponds, represent a foundational form of Indigenous aquaculture and coastal resource management. Once abundant across the islands, many loko iʻa have deteriorated due to neglect, development, and invasive species. Restoring these systems not only revitalizes traditional food production and strengthens biocultural connections but also creates ideal habitats for native limu to flourish. By understanding the conditions that support limu growth in loko iʻa, this research supports ongoing fishpond restoration efforts and highlights the interconnectedness of limu health and ecosystem stewardship.
This research is a collaborative effort rooted in community-based resource management, guided by the knowledge of local practitioners and organizations. By bridging cross-disciplinary efforts, we aim to develop practical recommendations that empower community-led restoration. Through purpose, place, and partnerships, this study contributes to revitalizing Hawaiʻi’s native marine resources.
Data collection is expected to conclude in early summer 2025, with results to follow shortly thereafter.