Wildlife of
Marshall Islands

Primary Threats

• Sea-level rise and increasing wave-driven flooding ("king tides") erode shorelines, contaminate fragile freshwater lenses, and force hardening/raising of coastlines that can degrade reefs. Marine heatwaves drive coral bleaching in atoll lagoons and outer reefs, reducing habitat complexity for reef fish and weakening natural coastal protection. Ocean acidification threatens calcifying organisms (corals, crustose coralline algae) that build reef structure.
• Pressure occurs at two scales: (1) local reef and lagoon fisheries that support food security, where concentrated harvesting near population centers (especially Majuro and Ebeye) can reduce key species and alter reef food webs; and (2) highly valuable industrial tuna fisheries across the EEZ, where sustainability depends on effective regional controls (effort limits, bycatch mitigation for sharks, turtles, seabirds).
• Solid waste and limited landfill capacity on small atolls lead to plastics and debris entering lagoons and reefs. In densely populated areas, inadequate wastewater treatment contributes nutrients and pathogens to nearshore waters, stressing corals and seagrass/algal habitats. The country also faces site-specific contamination issues associated with the nuclear testing legacy in parts of the northern atolls (long-term environmental monitoring and risk management needs).
• Invasive rats, ants, and other non-native species on small islets can devastate seabird colonies by preying on eggs/chicks or disrupting nesting habitat. Invasive plants can alter strand vegetation that stabilizes islets and provides nesting cover, reducing resilience to storms and erosion.
• Coastal erosion, storm damage, and land scarcity drive shoreline armoring, reclamation, and dredging for building materials and infrastructure. These activities can smother corals, reduce water quality in lagoons, and simplify natural shoreline habitats important for fish nursery areas and turtle nesting beaches.
• Dredging of reef flats and lagoon bottoms, creation of causeways, and channel modification for navigation and construction change currents and sediment dynamics in atolls. Altered circulation can increase stagnation or turbidity in lagoons, affecting coral health and nearshore fisheries productivity.
• Ports, seawalls, airports, and urban expansion on narrow atoll land strips often require reef excavation, fill, and coastal hardening. While critical for safety and services, these projects can fragment or degrade nearshore habitats and increase chronic sedimentation and turbidity.
• Freshwater is naturally limited to thin groundwater lenses; drought and saltwater intrusion reduce potable water and constrain vegetation, which in turn affects soil stability and coastal erosion risk. Reliance on reef fish for protein can intensify fishing pressure when imported food costs rise or supply chains are disrupted.
• Boat traffic, shoreline activity, and development near nesting beaches and seabird islets can disturb breeding, reduce nesting success, and increase light/noise impacts. Tourism and recreation are smaller-scale than in many Pacific states but can still concentrate on sensitive reef areas around Majuro and outer-atoll lagoons.
• Traditional take of sea turtles and seabirds has occurred historically; where it persists, it can affect slow-reproducing populations. Management is complicated by the cultural importance of customary harvest and the need for clear, enforceable seasonal/size/area rules.