Guam’s freshwater resources

Gallinula chloropus guamimasso ducks


Masso Reservoir

The opportunities for freshwater fishing on Guam are limited. With the numerous fishing derbies sponsored by Division of Aquatic and Wildlife Resources (DAWR) at Fena Lake not open to the general public, people have wanted more areas available for freshwater fishing. The reservoir could serve as an excellent resource for aquatic education and providing an area to promote freshwater fishing. The project will enhance recreational sportfishing opportunities in Masso Reservoir through dredging of the reservoir, rehabilitation of the water control gate structure, construction of a cofferdam, and development of the area for public access and shoreline fishing.

The US Navy constructed the Masso Reservoir in the early 1940’s for use as a potable water reservoir. It was abandoned in 1951 because siltation had made it unsuitable for water storage. In 1978, the Black Construction Company, working under contract to DAWR, cleared about two acres of the pond by removing the Phragmites grass. At that time, the retaining wall, spillway and sluice gate were repaired. The pond was stocked numerous times with red hybrid tilapia (Oreochromis mossambica X O. nilotica), tucunare or “peacock bass” Chichla ocellaris and mosquito fish (Gambusia sp.) at a rate to keep a natural balance in the reservoir. Because of poaching, poisoning, and vandalism, the project was discontinued. In 1993 the restoration project was revived because the DAWR has increased it’s enforcement staff and was then able to use fish restoration funds for “put and take” fishing. Because the projected cost of the project is approximately $1,300,000, it will be completed in phases. The biological survey has been completed and engineering plans drawn for the restoration. A cofferdam will be constructed first, due to environmental considerations for the endangered common moorhen using the reservoir. During the second phase, the reservoir will be dredged and the reservoir made fishable. The third phase will complete the project with a floating wharf and fishing platform, plus parking and restroom facilities.

The Guam Land Use Commission has approved the Wetland permit for the Masso Reservoir restoration project. In addition, the 401 Water Quality Certification was granted by the Guam Environmental Protection Agency (GEPA). Two acres of acacia trees (Acacia sp.) have been planted on the adjacent Government of Guam property. Seeds of native species were collected to plant 4 additional acres in the watershed.

Masso Reservoir/Nature Trail Project:

To view proposal, click on: Guam-Pitii-MassoNCWPfinalproposal