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Mālama Maunalua implements strategies to remove and prevent regrowth of invasive alien algae (IAA). The focus of our work is in the 28+ acres of Pāiko beach. Our goal is to clear the area of harmful algae to restore a marine habitat with healthy native seagrass, algae and coral.

Photo Credit: Trevor Johannsen

The problem: Invasive Alien Algae

Invasive Alien Algae (IAA) are one of the greatest threats to Hawai’i’s coral reefs and nearshore marine ecosystems. These invasive, non-native marine algae species flourish off of an environment created by sediment and runoff from the land.  As IAA spreads, it grows over and smothers coral reefs and native algal communities, killing extensive areas of native habitat.

Three species of invasive algae are devastating Maunalua Bay: Gorilla Ogo (Gracilaria salicornia), Prickly seaweed (Acanthophora spicifera), and Leather Mudweed (Avrainvillea lacerata, formerly amadelpha).

Restoration Projects Include:

  • Huki (large-scale, organized community events to “pull” or remove IAA at select plots)
  • Adopt-a-Plot (individuals trained to steward – huki and monitor – personal plots)
  • Sea Urchin Seeding and Biocontrol
  • Seagrass Transplanting

Photo Credit: Alex Awo

Photo Credit: Alex Awo

Educational

Educational huki events are intended for grade school students. These fun and informational events are a great way for students to learn more about the impacts of invasive alien algae on our island environment, specifically at Maunalua Bay. Students will identify both invasive and native algae species and will learn the important role that healthy watersheds play in maintaining healthy oceans. Students will put their knowledge into practice by participating in a huki (pull) and will remove invasive algae from the nearshore waters.

To date, one of Mālama Maunalua’s key initiatives in restoring the health of Maunalua Bay has involved removing invasive alien algae via regular volunteer-based hukis. Approximately 3,000 volunteers, including 1,000 students, participate in our 30+ community hukis every year, coming together to remove the Invasive Alien Algae (IAA) from Paiko beach. More than 4 million pounds have been removed and recycled as soil amendment at local farms. Even with scheduled hukis taking place several times a month, more volunteers are needed to help maintain the 1200 plots of IAA in Paiko beach. To ensure that we provide an enjoyable and safe volunteer experience for community of all ages, Mālama Maunalua staffs every Huki event with at least three knowledgeable team members. We appreciate every group and individual who gives their time to restore the Bay.  Learn more about our different types of huki events below. To volunteer at a huki, please view our calendar for open huki events to attend or schedule your own by contacting us at volunteer@malamamaunalua.org.

Community

Our community huki are volunteer-based events that bring the community together in order to restore the health of Maunalua Bay.  They are scheduled at least once a month on a Saturday, aligning with lower tides. Volunteers will learn about the problems facing the Bay as well as the three main types of invasive alien algae that we remove from the nearshore waters. On average, we host between 30-100 volunteers per event.

Corporate

Similar to community huki events, corporate huki take place with local participating organizations or businesses who are interested in having their employees or staff get involved and volunteer in environmental stewardship for a morning. Participants have the opportunity to learn about Mālama Maunalua and the work we do to restore the nearshore marine ecosystem, while also having time to bond with their colleagues and making an active effort to remove invasive algae.

Mālama Maunalua implemented an “Adopt a Plot” program in 2014 to provide an opportunity for community members to continuously be involved in improving the Bay. Many of these plots are smothered with invasive algae and need to be worked on by volunteers. Even with the large community groups participating in hukis multiple times a month, more volunteers are needed to help maintain these plots. As and Adopt a Plot volunteer you will receive your own 10X10m plot that you can clear and maintain on your own time. To volunteer to Adopt-a-Plot, please contact us at volunteer@malamamaunalua.org.

Commitment of a Mālama Maunalua Adopt-a-Plot volunteer:

  1. Complete a Mālama Maunalua orientation and Adopt a Plot training session, which includes information on: Equipment use and storage, GPS use for navigation, algae identification data assessments/reporting.
  2. Safeguard and properly store equipment.
  3. Adhere to water safety rules (I certify my ability to swim, and will always ensure all volunteers I engage are competent swimmers.)
  4. Maintain your adopted plots to a level less than 10% invasive algae for a minimum 1 year commitment.
  5. Learn how to conduct visual monitoring, and collect and submit data at least once a year.
  6. Track and submit your volunteer hours every quarter.

Roles and responsibilities of a Mālama Maunalua plot adoptee:

  1. Compile success stories and other feedback (positive and negative) to help MM improve and extend the Adopt-a-Plot program to other neighborhoods. Take pictures of activities in action, and submit pictures and articles to staff for monthly newsletters.
  2. Assist in spreading the word to others about what you and MM are doing to help Maunalua Bay and how they can learn and participate.

In addition to our huki events, Mālama Maunalua is tackling a new initiative that utilizes sea urchins to further reduce the abundance and effects of invasive alien algae on Hawai‘i’s reefs. Native collector urchins, Tripneustes gratilla, or Hāwa‘e maoli, are spawned and raised in captivity at the State’s Department of Land and Natural Resources Division of Aquatic Resources (DLNR-DAR) Ānuenue Fisheries Research Center. They are reared as a tool to combat invasive algal regrowth after the seaweed is removed by huki efforts. The herbivorous urchins act similar to cattle, grazing upon invasive regrowth and clearing overgrown reef to allow for native species and coral regeneration.

Phase I of the Native Collector Urchin Project was implemented in the summer of 2018 when 66 adult urchins were relocated from the deeper water in Maunalua Bay to the nearshore reef flat. From July – to December 2018, the Mālama Maunalua team monitored urchin health, invasive algal biomass, and urchin movement. Results found urchins were able to survive the relocation from deeper water to the nearshore reef flat and appeared to be eating all three three key species of invasive algae in the Bay, including leather mudweed.

As of October 2021, Mālama Maunalua and DLNR-DAR implemented Phase II of a partner-led sea urchin project continuing to utilize the native collector urchins Tripneustes gratilla as a bio-control mechanism to curb the growth and regrowth of invasive alien algae in Maunalua Bay within the Pāiko Restoration Area.

During Phase II, 6,000 juvenile urchins reared at DAR’s Ānuenue Fisheries Research Center’s sea urchin hatchery were outplanted in Maunalua Bay. This was in effort to help scale up our fight against invasive algae by targeting areas in Maunalua Bay that Mālama Maunalua could not manually huki with community volunteers due to constraints such as access and water depth.

As of July 2022, Phase III was launched with its goal to test a new cage design. This phase built upon the cage design used in Phase II and modifications were made to increase cage durability as well as the efficiency of monitoring urchins and conducting benthic surveys for urchin studies. Three cages were deployed with 6 juvenile Tripneustes gratilla per cage in the Paikō Restoration Area. The variables being observed are urchin survivorship, growth, and effect on the surrounding. With these new cages, Mālama Maunalua can improve their way of studying urchin survivorship and monitoring invasive alien algae coverage in the bay.

To learn more about this project and keep up to date visit www.facebook.com/noalienseaweed.

Photo credit: Laura Bailes

The native Hawaiian seagrass Halophila hawaiiana used to be a very dominant native species and once supported a diverse group of marine life in Maunalua Bay. However, with the rapid growth of invasive alien algae, the Bay shifted from a healthy diverse ecosystem to a seascape overrun with invasive algae and sediment. Mālama Maunalua is currently working with a consortium of experts in government, non-profit, and academic institutions to transplant the native seagrass into the areas that have been cleared from our huki events. Reestablishing seagrass beds will take time, but learning how to successfully transplant seagrass will speed up the overall restoration of Maunalua Bay.

Photo Credit: Alex Awo & Laura Bailes

In August 2022, over 600 juvenile oysters were placed in secured cages around Maunalua Bay. The oysters are triploid, sterile and cannot reproduce. After six months, with monitoring by a team of Oyster Fellows from the University of Hawaiʻi, the oysters are surviving and growing!

Oysters are nature’s most efficient water filters. They eat by pumping large volumes of water through their bodies capturing sediment and pollutants from the water column. Oysters are known to filter between 20 and 50 gallons of water per day removing harmful pollutants including bacteria, heavy metals, PCBs, oil, microplastics, bacterial pathogens, sunscreen chemicals, which improves water clarity and quality. In addition, they remove carbon from the water and use it to build their shells, underscoring their importance in our changing climate and marine environment.

MM is using the Pacific Oyster because of its rapid growth, ability to adapt to a wide range of environmental conditions, resistance to disease, plus ecosystem services. The Pacific Oyster was introduced to the Hawaiian Islands in the early 1920s to facilitate 
development of local bivalve aquaculture mainly at Pearl Harbor and Kaneohe Bay. To date, the Pacific Oyster has not out-competed Hawaiʻi’s native oyster or become widespread.

Maunalua Bay is the newest community using oysters to improve water quality and clarity in waters around the Hawaiian islands. Waterkeepers and UH Hilo’s Pacific Aquaculture and Coastal Resources Center (PACRC) have been at the forefront of out-planting over 10,000 oysters with a myriad of partners, including:

MM hopes that oysters will serve as an easy, cost-effective tool for remediation to help improve water quality in the Bay. Also, we are now helping other communities with our lessons learned. Special thanks to those who are supporting this project, especially the oyster cage stewards.

Please note: No oysters can be secured without the necessary permit from the Department of Land and Natural Resources and the Department of Agriculture. The Pacific oyster, commonly known as Crassostrea gigas, is now classified as Magallana gigas.

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