Researchers Unveil 'Super Sucker' New Alien Algae Removal Machine

Honolulu, Hawai'i—April 11, 2006—Marine researchers in Hawai'i have a new weapon in the battle against alien algae. They call it the “super sucker,” and it acts as an underwater vacuum cleaner to take invasive algae off the reef. Initials tests show it can remove up to 800 pounds in a single hour.

“The super sucker is potentially the difference between watching our reefs slowly succumb to alien algae and returning them to healthy productive ecosystems,” said Celia Smith, a professor and seaweed specialist in the University of Hawaii's Botany Department. “We’ve field tested this device and worked out the kinks, and I think we've established it’s a viable tool that can help us get a handle on the alien algae problem."

The new mechanical removal device has been fabricated and piloted in Kâne'ohe Bay, where it is operated by a small group of trained crewmembers from various partner agencies. The University of Hawai'i (UH), The Nature Conservancy, and the State Department of Land and Natural Resources / Division of Aquatic Resources are leading the effort.

The pilot project is one component of a larger strategy that includes community-based volunteer clean ups, the use of algae-eating native sea urchins, and the out planting of native algae to repopulate the reef. Local farmers are also involved, recycling the alien algae for use as a fertilizer to grow taro.

Alien algae are a serious threat to Hawaii’s coral reefs. They already dominate large regions of Kâne'ohe Bay and Oahu’s south shore, and are also abundant on the south shores of Maui and Moloka'i. In Kâne'ohe Bay, where the super sucker has been developed and tested, it is helping to fight fast-infesting invasive algae, including the particularly virulent Gracilaria salicornia, also known as gorilla ogo, and the gristly yellow-green Eucheuma. Both species overwhelm reefs with thick, tangled mats that smother and kill coral . According to Cynthia Hunter, an assistant professor in the UH Manoa Biology Program, Gracilaria fills in the reef and takes away habitat for fish. “It takes a very complex habitat with nooks and crevices and flattens it,” she said. “The coral can only recover if you get the alien algae off of it.”

Community based volunteer efforts to remove Gracilaria began in earnest three years ago in Waikîkî and have since spread to other parts of O'ahu. In total, 20 events involving 2,000 volunteers have removed more than 100 tons of the invasive seaweed. “The volunteer clean ups have been a tremendous success in educating the public and will continue to be an important educational compliment to the super sucker,” said Tony Montgomery, an aquatic biologist with the DLNR Division of Aquatic Resources. “But the problem is so pervasive, and the urgency so great, that we need additional tools.”

The idea for the super sucker came out of planning meetings with DLNR, botany and biology researchers, and was taken from concept to machine by The Nature Conservancy. Eric Co, the Conservancy’s O'ahu marine coordinator, researched and developed the device, which is essentially a modified gold dredger that has been outfitted with a 40-horsepower diesel engine and runs on bio-diesel fuel. "It's a Venturi system, which means there are no fans or blades that the collected algae pass through,” Co said. “This is important for two reasons: One, any marine life that is inadvertently collected can be returned. Two, alien algae can reproduce by fragmentation, so the fewer fragments we are collecting during the process, the better."

The super sucker is deployed from a 13 x 25-foot covered barge that is docked at the Hawai'i Institute of Marine Biology and was specifically designed for the project. The entire operation is accomplished with a five-person crew. Two divers, equipped with a four-inch round, 100-foot hose, descend below the surface, where they stuff the alien algae into the suction hose. Aboard the barge, algae and seawater are deposited onto a large porous bin, where sorters separate the by-catch and pack the algae in burlap sacks. The sacks are then delivered to local taro farmers Paul and Charlie Reppun, who have found the algae to be a superior fertilizer.

According to Brian Parscal, the UH operations supervisor for the project, the 800 pounds of alien algae the super sucker removes in an hour is equivalent to the effort generated by 150 volunteers and 10 divers. “The other great advantage of the super sucker is that it's portable,” he said. “It can be deployed in critical areas that are more remote, where manual removal efforts would be impractical or impossible.”

But cleaning the reef of alien algae is only half the battle. Gracilaria and other invasive algae species can quickly return and spreads at a rate of 250 to 300 meters a year. To prevent any new growth, researchers plan to release native sea urchins that feed on the alien algae, and out plant native algae in the cleaned areas. “In small-scale experiments, the urchins have flat out stopped the alien algae from growing back,” said Eric Conklin, the Conservancy's marine science advisor. “What we don’t know yet is how successful the urchins will be at the scale of cleaning entire reefs. And to some extent, how effective the program will be long term may depend on that. Can you clean an area with the super sucker and walk away, or do you need to keep coming back to keep up with the problem?”

Researchers said if the program can be shown to work over large areas, it could pave the way for funding to build additional super suckers. “At that point, we would be in a position to attack the problem at the scale that’s really needed,” Conklin said.

Initial funding for the super sucker has been provided by: The National Oceanic and Atmospheric Administration (NOAA), Hawai'i Community Foundation, National Fish and Wildlife Foundation, The Nature Conservancy, Hawai'i Invasive Species Council, and the National Sea Grant Program through the support of Hawaii Senator Daniel K. Inouye.