In the 1970s, to the chagrin of many in Hawai'i's marine science community, a handful of researchers imported non-native seaweeds for aquaculture experiments in the islands, some of which took place in Kane'ohe Bay. After the experiments were abandoned, the invasive algae Kappaphycus escaped culture and found its way into the bay's fragile ecosystem where it smothered corals, native seaweeds and other organisms by quickly spreading across the reef in thick, dense mats. In 2003, through a collaborative effort between scientists and conservationists, an underwater vacuum called the "Super Sucker" was developed to suck invasive algae off the reef. The Super Sucker was very successful at removing the invasive algae and exposing the coral, but it could not keep up with the rapid growth and spread of the alien algae.
Biologists from the Department of Land and Natural Resources Division of Aquatic Resources think they've found a long-term solution to work in concert with the Super Sucker: Tripneustes gratilla, a native Hawaiian collector urchin that naturally resides on flat reefs and grazes on seaweed. Experiments were conducted on a small reef patches near the Hawai'i Institute of Marine Biology on Coconut Island. The patch of reef was cleared with the Super Sucker and urchins were placed on half of the cleared area for one year.
The urchins thrived and kept the selected reef patch almost entirely free of invasive algae. Thrilled with the results, biologists are already planning their next experiment, moving the urchins to the un-grazed side of the reef patchÐwhich returned to pre-Super Sucker levelsÐto see if the grazers can handle thousands of pounds of invasive algae on their dinner plate.