Indonesia’s Disappearing Coral Reefs

Coral Reefs Indonesia Disappearing
Coral reef in Indonesian waters. Photo courtesy of Tiket2.

The Indonesian Institute of Sciences has found that one-third of Indonesia's 5.1 million hectares of coral reef are in a precarious state. Destructive fishing techniques, increased carbon dioxide emissions, and nutrient and sediment loading have all contributed to reef deterioration. The close proximity of coastal populations who are reliant on the biodiverse coral reefs for sustenance means that the destruction heavily impacts coastal welfare. According to the Coral Reef Economy, the positive effect of healthy coral reefs on Indonesia’s coastal fisheries, development, and tourism sectors could contribute an additional $37 billion to the economy by 2030. By understanding and addressing human-induced threats to the coral reefs, Indonesia can revitalize and sustain coastal economies. 

Destructive Fishing Techniques

Activities like cyanide fishing, dynamite fishing, and bottom trawling harm the delicate reef ecosystems. Dynamite fishing harms coral reef tissues, inhibits the recovery of adjacent colonies, and decimates local aquatic life. The corrosive effects of cyanide and the physical destruction left in the wake of bottom trawlers likewise severely damage the reefs. The Indonesian government has prohibited fishers from using dynamite and cyanide poisoning since 2004, with violators facing a maximum of five years of incarceration and up to $147,000 in fines. The use of illegal fishing techniques, however, continues to persist. On December 6th, authorities arrested three fishermen in East Nusa Tenggara province for using explosive devices. The incidents follow a larger trend where weak local maritime law enforcement capacity coupled with low catch rates leads to fishers employing illegal and destructive fishing techniques. 

Carbon Dioxide Emissions

Rising sea temperatures and ocean acidification cause coral bleaching, a process in which coral structures lose essential algae. The ocean absorbs roughly a quarter of the carbon emissions released by burning fossil fuel. The resulting chemical reactions have increased ocean-surface acidity levels by around 30 percent since the beginning of industrialization 200 years ago. The increased acidification ultimately makes it harder for corals to create their calcium skeletons. Meanwhile, increased concentrations of carbon emissions in the atmosphere, a process known as global warming, leads to an increase in ocean temperatures. This thermal stress causes coral bleaching, a condition that makes the organisms more susceptible to disease. In 1997, El Niño caused widespread coral bleaching in Indonesian reefs, leading to the mortality of over 90 percent of reefs off the Seribu islands. Likewise, climate-induced changes to coastal habitats, including altered ocean currents, storm patterns, and sea levels, all detrimentally affect coral reef vitality.  

Nutrient and Sediment Loading

Coastal agricultural and industrial centers contribute to nutrient loading of reef waters. Runoff with compounds like nitrogen and phosphorus disrupts the nutrient balance required for coral reef ecosystems to flourish. Likewise, a buildup of sedimentation levels from anthropogenic stressors including deforestation and drainage networks harms coral reef colonies by increasing turbidity. According to a study focusing on three Indonesian regions published in the Marine Pollution Bulletin, the combined impact of nutrient and sediment loading can cause a reduction in coral biodiversity of up to 60 percent in shallow depths. The strong effect of nutrient and sediment loading on shallow reefs means the impact on coastal communities is substantial.  

Conservation Measures 

Over the years, Indonesia has implemented several initiatives to facilitate conservation. In April 2019, Indonesia succeeded in designating a combined 191,400 square kilometers of its waters as marine protected areas. The government has also bolstered maritime law enforcement oversight by recruiting local volunteers to help monitor against illegal fishing activity. Room for improvement, however, continues to exist. A study published in the Annual Review of Marine Science, for example, concluded that although marine protected areas help manage local anthropogenic stressors, coral reefs will continue to decline at an alarming rate as a result of global warming. By increasing our understanding of how human activity impacts the coral reefs and building on existing conservation initiatives, Indonesia can address these environmental threats. 

Wider Ramifications for The Blue Economy: Maritime Security Index 

The Maritime Security Index launched by Stable Seas provides an overview of the maritime security challenges and mitigation efforts of 70 African and Asian countries. Indonesia’s above-average blue economy score in the the Maritime Security Index is indicative of how important marine resources are to the country. As detailed on the website’s country brief for Indonesia, a diverse blue economy has contributed to higher economic security. Without the reefs present to bolster the resilience of marine ecosystems, blue economy sectors like tourism and fishing would suffer, detracting from Indonesia's diverse economic exports.   


The degradation of coral reefs in Indonesia has serious ramifications for the marine environment and coastal welfare. Illegal fishing techniques, land-based runoffs, and pollution all whittle away at coral reef resilience, causing a reduction in biodiversity and fish stocks. The rapid rate of destruction currently experienced by coral reefs means decisive government action is essential to ensure their survival. By improving coral reef conservation measures on both local and national levels, Indonesia can enhance its blue economy potential and more effectively protect a vulnerable marine ecosystem.