As water temperatures rise due to climate change, Hawaiian fish ponds may offer some species a respite.
Loko kuapā are coastal ponds that Native Hawaiians created by enclosing a portion of the ocean with a rock wall.
These ponds are also fed by freshwater streams or springs. The pond's rock walls help to retain nutrient-rich fresh water, which supports fish populations within the pond.
Researcher Annie Innes-Gold said this design also helps to regulate temperature, allowing the pond to reach cooler temperatures than nearby waters.
Innes-Gold and her team reviewed temperature data from loko kuapā at Kāneʻohe Bay, and compared it with data from the surrounding bay and estuary.
They found that in the winter months, water temperatures within those fish ponds were lower by about 5 degrees Fahrenheit.
These cooler conditions may help fish species like the ʻamaʻama, or striped mullet, withstand climate change, said Innes-Gold.
She added that these findings highlight the significance of Hawaiʻi's freshwater resources.
"The most important applications that I see in this work is just to continue to advocate for the importance of fresh water in these ecosystems, and making sure we have enough fresh water in the streams to bring them back to the conditions that made loko iʻa productive, historically," she said.
