A new study by the University of Hawaiʻi at Mānoa’s Hawaiʻi Institute of Marine Biology (HIMB) underscores the ecological value of traditional Hawaiian fishponds, or “loko iʻa.” Today, these fishponds have emerged as an important model for building climate resilience. Tuan’s research emphasizes the important protective role that ancient aquaculture systems can play in mitigating the effects of climate change on fish. It further demonstrates how Indigenous knowledge can be successfully and effectively applied in today’s modern scientific practice.
The study, titled “Restoration and management of an Indigenous aquaculture system helps mitigate climate change impacts to estuarine fisheries,” was led by Annie Innes-Gold, a recent Ph.D. graduate from the University of Hawaiʻi. Those results released in the journal npj Ocean Sustainability emphasize an important fact. As fish populations continue to be challenged by climate change, traditional fishponds offer an important way to increase their resilience.
Traditional Hawaiian fishponds are an attractive set of natural capital that can act as a buffer to environmental stressors. The research shows that loko iʻa support more fish than surrounding estuarine areas and have healthier fish populations overall. This temporary resilience is due to the unique temperature regulation that large freshwater inputs, like the Columbia, provide. This regulation is key for the conservation of aquatic life.
The research underscores the importance of restoring and managing these traditional systems, not only for ecological health but for social and cultural benefits. These detailed maps and model schematics from this study help depict the complex interactions between loko iʻa and their environments.
“Loko iʻa are a system unique to Hawaiʻi, and their restoration can have wide–reaching benefits including cultural preservation, education, healthy ecosystems, and now—from what we found in our study—also climate resilience.”
It paints a grim picture of how increasing water temperatures can negatively impact vulnerable fish populations. The fish that live in loko iʻa are turning out to be hardier. Innes-Gold noted:
These results underscore the important influence of freshwater inputs as a moderating force on temperature. In addition to their rewilding work, they make biocultural restoration integral to their work. Innes-Gold concluded:
“Our study is one of the first in academic literature to compare the temperatures between loko iʻa and the surrounding bay and how these temperature differences may be reflected in potential fish productivity.”
The results indicate that while rising water temperatures may negatively affect fish populations, those within loko iʻa demonstrate greater resilience. Innes-Gold noted:
“We found that although rising water temperature may lead to declines in fish populations, loko iʻa fish populations were more resilient to rising water temperatures than those in the surrounding estuary. This result is likely due to the temperature regulation that the loko iʻa receives from freshwater input, both at the surface and below the ground.”
Moreover, these findings highlight the critical role of freshwater inputs in regulating temperature and emphasize the importance of biocultural restoration. Innes-Gold concluded:
“They also support the importance of biocultural restoration in terms of enhancing fish populations and increasing social–ecological resilience in a changing climate.”