story by Chris Pala
photo by Chris McDonough
Take a walk along O‘ahu’s scenic Kane‘ohe Bay—or better still, snorkel to the reefs on its northwest side—and you’re likely to come across a strange contraption: a giant vacuum cleaner mounted on a pontoon boat. Developed here in Hawai‘i, it’s called the Super Sucker. It’s our first line of defense against an invasive alga called Eucheuma that is spreading across the bay and turning high-diversity, healthy reefs into algae-smothered wastelands.
The alga was introduced into Kane‘ohe Bay, with the best of intentions, in the 1970s by Max Doty, a professor of marine botany at the University of Hawai‘i. Doty, who died a decade ago, noted that Eucheuma was rich in carrageenan, an emulsifier and fat substitute. The impoverished peoples of the world’s tropical coasts, he theorized, could farm it profitably. So he brought it from the Philippines to his Coconut Island marine lab in Kane‘ohe Bay and experimented to find the most efficient way to propagate it. In one sense, Doty’s experiments were a success: Two dozen countries around the world have since adopted his method, and now 120,000 dry tons a year are being produced. Today, carrageenan, which is in everything from toothpaste to beer, ice cream, hamburgers, floor wax and pills, is being farmed cheaply from the Philippines to Zanzibar.
But for Kane‘ohe Bay, Doty’s experiments were a catastrophe. In the ’90s, scientists discovered that Eucheuma had spread far into the bay. Doty’s successor, Professor Celia Smith, surveyed the damage and concluded that some kind of vacuum cleaner might be the solution. The Nature Conservancy funded it, the state staffed it, and Eric Co, a biologist at the Conservancy, built it. “The closest model I could find was a gold dredger I saw in California,” Co says.
It took three years to build and test the Super Sucker. Last summer the $60,000 machine started full-time work along with a smaller, more versatile $50,000 version, the Super Sucker Jr., designed for work on shallow reefs. So far, they’ve been effective: The vacuums can suck up 800 pounds of algae per hour and clear hundreds of square feet of reef in a day (the algae, which decays into a superior fertilizer, is donated to taro farmers). Once an area has been cleared, native algae, fish and corals are able to re-establish themselves, thus impeding Eucheuma’s return. “We may not be able to eradicate it,” says Smith, “but I’m reasonably confident we can bring it under control.” As for the machine’s dubious name, says Dr. Eric Conklin of The Nature Conservancy, it’s here to stay. “At first we called it ‘Super Sucker’ as a joke,” he says, “but we couldn’t find a more official and important name, so it stuck.” HH