Manell-Geus, Guam


Manell-Geus, Guam

The Manell-Geus Habitat Focus Area lies at the southern tip of the island of Guam. The area includes the island’s only shallow water lagoon, as well as fringing reefs, mangroves, and extensive seagrass beds. These beds extend eastward into the Achang Reef Flat Marine Preserve, providing valuable nursery habitat for a variety of desirable food fish including:

  • Mafute (Lethrinus harak, the thumbprint emperor)
  • Tiao (juvenile Mullids or goatfish)
  • Manahak (juvenile Siganids)

Located primarily in the village of Merizo, the rivers and reefs associated with this watershed support the village’s strong fishing tradition. The area is also an important habitat for green and hawksbill sea turtles and has the largest aggregation of sea turtles observed on Guam.


Large purple starfish, called a Crown of Thorns
Invasive crown of thorns starfish.

While this site has amazing marine resources, the coastal ecosystem is impacted by poor water quality linked to erosion on the steep hillsides and along streambanks. Wildland fires, feral animals, and off-roading vehicles have accelerated the erosion. These conditions can lead to flooding in downstream areas, affecting the village and its adjacent reef.

Sedimentation can have serious impacts to coral health by increasing susceptibility to disease, decreasing growth rates, and affecting coral settlement. These problems are made worse by outbreaks of crown-of-thorns starfish (a carnivorous predator that preys on reef coral polyps) and overharvesting of key species such as large parrotfish.


  • Improve reef ecosystem health by reducing coral predation and nuisance algae
  • Improve community safety and health by reducing impacts from fires and floods
  • Maintain or improve local food production and marine tourism opportunities for Merizo
  • Improve community engagement in watershed and marine resource management


NOAA joins a diverse group of partners including federal agencies such as the Natural Resource Conservation Service, Guam Department of Agriculture, Bureau of Statistics and Plans, educational institutions, and the people of the village of Merizo.

Panoramic of a demonstration site in Manell-Geus, Guam


  • Conducted biophysical and socioeconomic surveys to collect baseline data to inform HFA activities.
  • Implemented watershed restoration practices including reforestation and installation of sediment control measures by working with community members and partners.
  • Supported development of a coral nursery and outplanting of corals with community volunteers.
  • Developed and implemented strategies to address nuisance algae and coral predation in the HFA.