Tackling Invasive Algae

Community Contributed

By Cheryl Corbiell

The Molokai Gorilla Ogo Survey and Control Project was launched on Saturday, June 6 at Kulana `Oiwi by master of ceremony and Office of Hawaiian Affairs Trustee Colette Machado. She was joined by 75 people with passion, knowledge and love for the reef and ocean. For five hours, participants learned about the threat and distribution of the invasive algae on Molokai’s south shore and what other communities have tackled gorilla ogo.

Over the last seven weeks, Machado has gathered seven project partners: Kua Aina Ulu Auamo, OHA, DLNR’s Division of Aquatic Resources (DAR), The Nature Conservancy (TNC), Ke Kua`aina Hanauna Hou, and Kahina Pohaku Loko I`a.

In the morning, Kimo Franklin of Malama Maunalua discussed the lessons learned from the ongoing invasive alien algae (IAA) cleanup at Maunalua Bay. More than 200 acres of the eight-mile bay was invaded with IAA. The IAA smothers coral reefs and native algae communities. Since 2007, 3000 volunteer have cleared 27 acres using and donated 10,000 hours.

“The main lessons for Molokai are the impossible is possible,” said Franklin, “start small and get visible success, get community involvement and partnerships, logistics are important from how to remove the algae to where to dispose it, and science plays a critical role in the survey and monitoring of the areas.”

Ogo removal was the next topic. Manuel Mejia of TNC prefers manual methods.

“One hundred volunteers over a four-hour event can remove 30,000 pounds of invasive ogo,” said Mejia. Another option is TNC has a large underwater vacuum called the “super sucker” that literally vacuums up the ogo, but it requires the right seafloor conditions to use it.

Via Skype, Charlie, Paul and Fred Reppun, taro farmers from Waiahole Valley, Oahu, described how they use invasive ogo as a soil amendment on their 10-acre farm. Alien ogo from Kaneohe Bay is delivered in bags, spread out, and dried in the sun. It is a potassium source for taro and sweet potato crops. The brothers are experimenting with a homemade digester to retain more ogo nutrients.

Molokai High School students Sarah and Lily Jenkins provided a historical perspective about mangrove introduction and gorilla ogo. Today, over 66 percent of Molokai’s fishponds are covered with mangroves, and over the next 100 years over 64 percent of the reef will be covered if nothing is done. Mangroves change water quality and produce sheltered mudflats, which are prime IAA habitat.

Another panel member, Sarah Vasconcellos, a doctoral Botany student at UH Manoa, described her success with native limu propagation. The research was conducted on the reef fronting the Waikiki Aquarium. Quarterly cleanups remove the invasive algae and native limu is planted in its place. Hoaka Thomas, a biology student at UH Manoa, presented his research about the introduction of red urchins into areas where gorilla ogo was cleared.

“The urchins can do the much harder, tedious work of grazing the little bits of algae,” said Hoaka. The strategy has worked in small test plots. This is a possibility for Molokai.

The next phase is July 11-13, when Molokai volunteers will participate in the south shore survey. Approximately six teams of half a dozen people per team will survey and GPS the south shore for gorilla ogo and mangroves. To volunteer, call Office of Hawaiian Affairs Molokai at 808-560-3611.