U.S. Coral Reef Task Force

A blue and black fish and a school of tan and black fish hover over a tan coral colony

Commonwealth of the Northern Mariana Islands

Map showing the islands in the Commonwealth of the Northern Mariana Islands

The Commonwealth of the Northern Mariana Islands (CNMI) is an unincorporated U.S. territory in the Western Pacific. It consists of the three largest and most populous islands, Saipan, Tinian, and Rota; three smaller inhabited islands, Anatahan, Alamagan, and Agrihan; one island that was inhabited up until a volcanic eruption in the 1980s, Pagan; and seven other uninhabited islands. The CNMI islands form a combined landmass of 179.151 mi2 (464 km2) [1].

The waters of the CNMI host 63 mi2  (162 km2) of coral reef ecosystem [2]. 

The CNMI’s reefs are home to

256 coral species

1,000+ fish species

[3]
Diver performing a survey with school of fish swimming among an active reef

Reef Threats

Land based sources of pollution on reefs icon
Invasive species icon
Environmental change icon

Land-Based Sources of Pollution

Invasive and Nuisance Species

Environmental Change

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  • Nonpoint source pollution is a leading cause of coral reef degradation in the southern CNMI. Water quality is particularly impacted by urban runoff, failing sewage systems, unpaved roads, farms, land clearing, and development [4]. 
  • Harmful soil erosion and sediment runoff are locally caused by poor erosion control during construction, and deforestation from frequent wildfires and invasive pigs and deer.
  • Growing populations and increased development have caused land-based threats such as polluted stormwater runoff and nutrient discharge, leading to algal blooms that continuously smother coral and compromise reef health and resilience.
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  • Environmental changes have caused some species to reproduce in large numbers, upsetting the ecosystem balance, including nuisance species such as the crown-of-thorn sea stars (COTS), Drupella snails, and Terpios sponges. 
  • Such species have exacerbated the stress of reefs by preying on corals and outcompeting other species during outbreaks.
  • Ongoing spread of nuisance species, such as crown-of-thorns starfish (COTS) outbreaks, with densities reaching 48 times higher than the average recorded over the past twenty years, has exacerbated coral decline and caused significant hindrances to reef recovery [5].
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  • The CNMIs’ distinctive traditions, landscape, and dependence on natural resources make the islands particularly vulnerable to the impacts of global environmental change, such as increasing sea surface temperatures, ocean acidification, rising sea levels, intensifying storms, and changing rainfall patterns.  
  • The coral reefs in the CNMI are in a continual state of recovery from past mass bleaching events, notably those in 2013, 2014, and 2017, which resulted in over a 60% loss of total coral cover in shallow reef sites around Saipan [6].

Reef Protections

  • The CNMI is home to 6 locally-managed marine preserves, with 5 of the preserves on Saipan and 1 on Rota. No take preserves include Sasanhaya Bay Fish Reserve in Rota (est. 1994), and Mañagaha Marine Conservation Area (est. 2000), Bird Island Sanctuary (est. 2001), and Forbidden Island Sanctuary (est. 2001) on Saipan. The remaining two preserves also reside on Saipan and include the Laolao Bay Sea Cucumber Sanctuary (est. 1996), which bans sea cucumber harvest, and the Lighthouse Reef Trochus Sanctuary (est. 1996), which bans trochus harvest [7].
  • The CNMI passed the Coral Reef Protection Act of 2018 (PL 20-79) to protect coral reefs from vessel damage through financial compensation. Although this law will be implemented once regulations are established, the DFW’s Enforcement Section’s Conservation Officers have received training from the Coral Reef Restoration Coordinator in preparation for the law to come into effect. 
  • In November of 2024, at the 49th USCRTF Meeting held in Saipan, CNMI Governor Arnold I. Palacios signed Executive Order 2025-001, declaring CNMI’s Reefs as Critical Natural Infrastructure, directing their protections at both federal and local levels, and calling on agencies to align regulations with Federal Partners for streamlined protection.
Coastline image from the Commonwealth of the Northern Mariana Islands

Bright Spots and On-Going Initiatives

Diver performing work on corals hanging from a tree structure in a coral nursery

The CNMI has 2 active coral restoration nurseries, both of which are in the Saipan West Lagoon.

  • The first nursery was established in 2019 by local NGO Johnston Applied Marine Sciences (JAMS) with funding from NOAA. Their nursery now has 23 coral trees and 4 tables with corals from 11 different local species, including the endangered Acropora globiceps. 
  • The second nursery is known as the CNMI Government nursery and has six trees, two tables, a small rope nursery section, and is working to expand its capacity in the coming year.
Group shot of participants in MINA’s Tasi Watch Ranger Program

To support reef education and engagement, local NGOs such as the Mariana Island Nature Alliance (MINA) provide training to community members to become conservation messengers [8].

  • MINA’s Tasi Watch Ranger Program, formed in 2010, recruits high school graduates, teaching them about the threats facing our fragile marine environment. The rangers serve as an effective means of communication with their peers, families, villages, and the wider island population. 
  • They get basic training in report writing, monitoring, ecology, outreach, community enforcement, data collection, and surveying, and are encouraged to provide written statements or testimonies to report witnessed violations.
Group photo in CNMI. Participants are holding a banner that reads Tides of Stewardship.

Each year in June, the CNMI hosts Ocean Month to celebrate the Marianas’ rich coastal resources and promote sustainable stewardship. Ocean Month includes educational events and activities such as beach cleanups, ocean-themed movie nights, free swimming and fishing lessons, and Ocean Fairs held on Saipan, Tinian, and Rota. [9] During Ocean Month in 2024, over 100 coastal families participated in Ocean Fairs. [10]

Logos on environmental management agencies in CNMI

The reefs of the CNMI are primarily managed by agencies affiliated with the Coral Reef Initiative (CRI), including: the Division of Fish and Wildlife (DFW) under the Department of Lands and Natural Resources (DLNR), the Division of Coastal Resource Management (DCRM), which currently houses the Coral Reef Initiative (CRI), and the Division of Environmental Quality (DEQ) under the Bureau of Environmental and Coastal Quality (BECQ). By fiscal year 2025, the CRI will be housed under the DLNR office of the Secretary. CRI agencies also receive support from the Office of Planning and Development (OPD), the Department of Public Lands (DPL), and DLNR’s Division of Agriculture (DOA) and Division of Parks and Recreation (DPR). [8]

Check out their websites to learn more about their work!

DLNR Coral Reef Restoration Program

DCRM Coral Reef Initiative

Connect with CRI on social media @cnmicri and @goingcoastal_cnmi

Two fish swimming on a coral reef.
Underwater coral reef scene with several swimming fish
Bleached coral
Small white fish swimming in front of a bleached coral
Large school of fish swimming in tight formation

Other resources to explore

Sources cited