Co-developing an eDNA toolkit for fishpond communities
March 17, 2025
On the windward side of Oʻahu, Hawaiʻi, the ahupuaʻa (social-ecological land division) of Heʻeia was a thriving ecosystem producing food and natural resources throughout the landscape. However, in the past century, changes in land use management and abandonment of Indigenous resource management practices led to poor ecosystem vitality and proliferation of invasive species, including but not limited to California grass, red mangrove, and aquarium fish species.
Since the early 2000s, major efforts were made to engage in biocultural restoration in Heʻeia by Indigenous-led, non-profit community organizations such as Paepae o Heʻeia and Kākoʻo ʻŌiwi. Their work aimed to restore the thriving abundance of Heʻeia through land management practices guided by Native Hawaiian values. As native birds and fish began to return to the landscape, the next step was to develop strategies that accounted for ongoing anthropogenic changes, such as extreme weather and sea level rise.
In a project funded by the Pacific Islands Climate Adaptation Science Center (PI-CASC), “Effect of extreme tidal events on future sea-level rise scenarios for He‘eia fish communities undergoing ahupua‘a restoration,” and in partnership with Heʻeia National Estuarine Research Reserve (NERR), Paepae o Heʻeia, and Kuaʻāina Ulu ʻAuamo, researchers explored the application of environmental DNA (eDNA) to assess the impact of King Tides, as proxy for future rising sea levels, on fish communities in the Heʻeia estuary. Unique to each organism, DNA is shed in various forms in the environment, such as mucus, scales, and skin. This DNA found in the environment (hence, eDNA) is sampled in water or soil, extracted, and analyzed to provide clues on the types of organisms in that space.
“There’s a number of ways that DNA gets into the environment,” said Shimi Rii, principal investigator and research coordinator at Heʻeia NERR. “We are not sampling from the fish directly, but looking for those traces of fish by whatever they’ve left off in the water. Then, using that information, we try to see if there’s any co-occurrence between what’s changing in the environment and within the communities,” she explained.
In this way, eDNA can be used to assess how fish diversity varies throughout the Heʻeia watershed over a seasonal time frame, especially during extreme tidal fluctuations.
As part of this project, Heʻeia NERR worked with several fishpond organization partners to develop an eDNA Toolkit.
“We wanted to try to conduct community-driven science that thinks about its ramifications on the community and co-develop research from the start of the project,” said Rii. “Thinking about what it means to be partners right at the onset or even at the beginning of the project.”
The goal was to create a guide for other organizations interested in utilizing eDNA. The toolkit would be used as a supplemental tool to learn more about the species, native and invasive, that are present in their areas and adjust management to respond to changes that may occur.
The idea came from multiple conversations with stewardship practitioners during restoration activities. It was further developed in one particular workshop hosted by Waikalua Loko Iʻa, in partnership with Mālama Loko Ea in Haleʻiwa, which helped to inform several facets of the toolkit. One activity conducted during the workshop discussed what eDNA is and how it can used to map species to the sampled locations and asked participants to formulate other questions about their sites.
The results of the activity were fruitful, so it was replicated and tailored to other organizational scenarios, such as with school groups as an educational activity or, more recently, in a workshop co-hosted with Kachemak Bay NERR in Homer, Alaska. The workshop, held in July 2024, gathered agencies, management, conservation organizations, and tribal entities to talk and explore how eDNA can be integrated into environmental monitoring and conservation strategies in Alaska while addressing community-driven research questions and data sovereignty topics.
Currently, the toolkit is being tested out by several organizations who have an interest in looking for ʻoʻopu, native and endemic species of gobies that are bioindicators of stream health in an ahupuaʻa, or examining how the biodiversity of different species of fish, limu (marine algae), or plankton can inform seasonal environmental changes.
The project plans to continue to distribute the toolkit, reaching out to the broader stewardship organization communities for usage and additional feedback.
“Our team hopes that the toolkit will serve as a living document, adapting to the needs of each community to help build capacity and increase agency within that organization to address the questions they have about their place,” said Rii.
