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Kaneohe Sea Urchin Hatchery Turns 10

Courtesy DLNR/DAR

A state effort using a native sea urchin to combat invasive seaweed has reached a big milestone. More than a decade ago, the state established a sea urchin hatchery to control an algae that could kill coral reefs in Kaneohe Bay.

In January 2011, scientists successfully moved juvenile sea urchins from the hatchery into the bay.

A decade later, more than 600,000 hatchery-raised urchins have helped treat nearly 230 acres of reef in Kaneohe.

Hatchery manager Dave Cohen says raising sea urchins is a very complicated process, but it's the most effective way to combat the invasive seaweed.

"In Kaneohe Bay, we can clear the reef mechanically, or we can remove the seaweed by hand. But if we don't put something there to maintain the area, then the seaweed will grow back," Cohen says. "And when we put urchins out on the reef, they act like little goats, or little gardeners, and they continue to work their way around the reef and eat the invasive seaweed. If we were to do this mechanically, it would be like cutting the lawn. We would have to go out every six to eight months and remove the seaweed."

Cohen says they are using some of the urchins in Waikiki to control other algae, such as gorilla ogo.

Casey Harlow is an HPR reporter and occasionally fills in as local host of Morning Edition and All Things Considered. Contact him at charlow@hawaiipublicradio.org or on Twitter (@CaseyHarlow).
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