Can fishponds help Hawaiʻi’s food security?

Indigenous aquaculture systems in Hawaiʻi, known as loko iʻa or fishponds, are known to increase fish populations in the pond and help protect water quality. A new study, supported by the Heʻeia Reserve, found that loko iʻa actually increase fish populations outside of the ponds, as well. 

“We have heard people voice the idea that historically, loko iʻa provided nursery grounds that may have supplemented fish populations in the estuary,” says Anne Innes-Gold, the study’s lead author and marine biology PhD candidate at the Reserve’s Partner, University of Hawaii. “Our study is the first that we are aware of to demonstrate this idea in academic literature.”

Historically, Hawaii’s loko iʻa produced almost 2 million pounds of fish annually and were managed with a “take what you need” mentality. Most were destroyed in the 20th century; by 1994 only six were still operating. Today, local aquaculture supplies less than 1 percent of the 70 million pounds of locally available seafood. Restoring loko iʻa has the potential to significantly increase the contribution of local aquaculture.

The Heʻeia Fishpond is stewarded by Native Hawaiian nonprofit, Paepae o Heʻeia, with Reserve support. Created 800 years ago, it has one of the longest walls of any fishpond in the Hawaiian Islands. The team is almost finished restoring it, although fishponds are never quite “done;” managing them is a cycle in which walls are continually maintained as people work to restore the ecological balance in and around the fishpond.

“This new study focuses on the Heʻeia fishpond, but helps to tell the larger story of how community based efforts of restoring loko iʻa can benefit the larger fishery,” says Hiʻilei Kawelo, founder and executive director of Paepae o Heʻeia.

The restoration work recently got a boost from the Bipartisan Infrastructure Law (BIL), which is providing funds to restore 40 acres above the Heʻeia fishpond and help protect it from flooding and storms. These lands are managed by Kākoʻo ʻŌiwi, a collaborative Native Hawaiian NGO that uses loʻi wai (wetland agroecology) to increase community resilience in regard to climate change, food security, and economic stability. 

A guiding principle of ahupuaʻa (social-ecological community) management is to not affect downstream users negatively. When one uses water, it is returned cleaner—a practice that has been honed over centuries. As spring waters and rainwater flow downhill, they collect nutrients, sediment and runoff. Instead of flushing directly to the ocean—which impacts water quality and coral reefs—these waters are filtered through loʻi wai (wetland agroecology) and then to the fishpond. Some of the nutrients collected in the fishpond feed plankton, which in turn nourishes the overall ecosystem.

Invasive species removed for the restoration of the fishpond, such as mangroves, are used to build mākāhā (sluice gates) with openings small enough to keep predators out, but wide enough for baby fish to enter. (They are swept in with the tide and attracted by the smell of nutrients.) The fishpond acts as a nursery, protecting the baby fish from the larger ocean environment and providing them with plentiful food. They come and go as they please until they grow too large to swim out of the gates.

“The goal is to make it easier for the community to eat from the ocean, but also help to repopulate and create safe spaces for fish to flourish,” says Aimee Sato, who recently stepped into the newly created role of Indigenous Stewardship Specialist, the Reserve’s version of a Stewardship Coordinator. “The system regenerates rather than extracts.” 

“As aquaculture continues to provide a growing proportion of our seafood globally, revival of Indigenous aquaculture systems will be beneficial to sustainably maintain and increase our seafood supply,” said the study’s lead author and marine biology PhD candidate Anne Innes-Gold. 

Restoring loko iʻa can help boost local food production to increase coastal resiliency, as well as provide community members with a space to nourish their bodies and minds, connect with ʻāina or “that which feeds,” practice reciprocity and promote Hawaiʻi lifeways.

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