The pressures on the region
There are many threats to the Coral Triangle. Overfishing, destructive fishing, pollution and coastal development are all direct threats to the habitats and resources of the region. On top of those direct threats lie the ever-increasing impacts of the changing climate. Climate change results in weakened coral reefs through bleaching and ocean acidification, while rising sea levels and increasing storm frequency threaten coastlines and coastal communities.
Overfishing is driven by extremely high population density, especially in the western Coral Triangle where even small islands are occupied. Coupled with large fleets of commercial trawlers and purse-seiners, there is strong evidence that many of the fisheries in the Coral Triangle are overfished or nearing their limits. Some fisheries, particularly for coral reef fish and sea cucumbers, are well beyond their limits of sustainability. In some areas, destructive practices employing explosives or poisons are devastating reefs.
The governments of the region, supported by non-governmental organisations, academia and some companies, are working to improve resource management and protection. The six governments signed the Coral Triangle Initiative Regional Plan of Action in 2009. Together they have committed to conserving the region's marine wealth for sustainable use. This includes declaring more protected areas, particularly in important habitats. Existing protected areas must also be better managed — many are only "paper parks" without any real management on the ground.
To address overfishing, the countries are turning to a new paradigm that shifts the focus of management from just the fish to include the environment the fish live in and the fishers who target them. This system, called the ecosystem approach to fisheries management, requires substantial changes in practice. The countries are also working to stop illegal, unreported and unregulated fishing in the region.
The one process now going on that will take millions of years to correct is the loss of genetic and species diversity by the destruction of natural habitats. This is the folly our descendants are least likely to forgive us. — E. O. Wilson
Five serious threats to the Coral Triangle
1. Overfishing
One of the biggest threats to the marine resources of the Coral Triangle is overfishing, which occurs when fish populations are unable to replenish themselves because too many are caught. It is considered the most widespread local threat to coral reefs in the region.
Specific fisheries for groupers and wrasses, aquarium fish, and some invertebrates such as sea cucumber are heavily exploited. Bottom trawling, where nets are dragged across the sea floor, is still prevalent in many areas, and demersal fish populations in heavily trawled regions have declined by as much as 95% since the 1960s.
Overfishing in the region is driven by the large and dense human populations in some areas, as well as by increased demand for seafood from North America, Europe and East Asia. Tuna, shrimp and live reef fish are just some of the products that move from the Coral Triangle around the world.
2. Destructive fishing
Destructive fishing is a particular threat where the act of fishing actually destroys the habitats and ecosystems on which fish populations depend. Fishing with explosives (variously called bomb, blast or dynamite fishing), cyanide fishing and bottom trawling are the most widespread forms in the Coral Triangle. Both bomb fishing and cyanide fishing are illegal throughout the region.
Bomb fishing originated with the use of unexploded Second World War munitions and has grown into a practice using explosives fashioned from bottles and fertiliser. The bombs have rudimentary fuses and are thrown from a small boat onto a reef; the underwater explosion stuns and kills many fish in the vicinity. They often explode close to the corals and blow up large areas of reef, damage that can take decades to recover. Bomb fishing is also dangerous — every year many fishers are injured fabricating and using these devices.
Cyanide fishing is one form of poison fishing used in the region. Fishermen dive on a reef, often with a rudimentary hookah rig, carrying a squeeze bottle of sodium cyanide. When a target fish is spotted, the poison is squirted into the reef where the fish is hiding and the fish is stunned. To retrieve it, corals are often broken, and the poison can kill the corals where it was applied.
3. Climate change
A changing climate is projected to have profound impacts on the Coral Triangle. Increased incidents of coral bleaching from elevated sea temperatures threaten the future of the reefs. Acidification of seawater threatens any organism that makes a calcium-carbonate shell, including many molluscs, crustaceans and corals. More frequent and more powerful storms, combined with sea level rise, will change the shape of small islands and beaches and may erode them away entirely. Increased temperatures even influence the sex of hatchling turtles, producing more females when nests are slightly warmer than usual. Human communities in the Coral Triangle, many of whom already live with very few resources, are particularly exposed as their ways of life and home islands come under threat.
4. Land-based pollution
Runoff from logging, agriculture, development and cities brings large amounts of sediment, fertiliser and chemicals to coastal areas. When land-based activities are conducted without regard for their potential impact, the effect can be devastating. Poorly conducted logging and conversion to agriculture can result in tonnes of excess sediment washing down rivers, eventually settling on coral reefs and smothering the corals. Fertilisers and sewage from human settlements can cause algal blooms that outcompete corals and eventually kill them.
This is where the built environment and marine conservation meet directly. Setback rules, on-site wastewater treatment, retained mangrove belts and construction practices that control erosion during building are, in practical terms, reef protection measures.
5. Wildlife trade
All species of marine turtle in the Coral Triangle are threatened with extinction (there is a lack of data on the flatback turtle). Their complex life histories expose them to many threats: being caught inadvertently in fishing gear, hunted for their shells and meat, having their eggs dug up and consumed, or losing nesting beaches to degradation and development.
Many other species in the region are threatened with extinction, including dugongs (hunting and loss of grazing grounds), seahorses (international trade in dried specimens), many shark species, groupers, and the humphead wrasse (Cheilinus undulatus).
Bycatch: the cost that never reaches a market
Bottom trawling illustrates the problem more clearly than any other gear type. A trawl dragged across the sea floor catches whatever is in its path, and a large share of that catch has no commercial value and is discarded. Marine turtles are among the most visible casualties: caught in trawl nets, they drown before the net is hauled. Turtle excluder devices reduce this substantially and are mandated in some fisheries in the region, but enforcement across thousands of vessels and thousands of kilometres of coast remains the limiting factor.
The wider point is that the damage from destructive gear is invisible in the landings data. What arrives at the market is only the fraction that sold; the reef structure broken, the juveniles killed and the turtles drowned never appear in a catch statistic. Ecosystem-based management exists precisely to bring those costs back into the accounting.
What is being done
Alongside the Coral Triangle Initiative Regional Plan of Action, work is happening at every scale: national marine protected area networks, locally managed marine areas run by village authorities, gear restrictions and seasonal closures, spawning aggregation protection, community patrols, turtle nesting beach protection, and certification schemes for fisheries and tourism operators.
Sustained funding is the recurring constraint. Marine park entrance fees, conservation trust funds, debt-for-nature swaps, blue bonds and payments for ecosystem services are all being used in the region to convert one-off grants into recurring income for management. The Coral Triangle overview on the homepage covers those financing mechanisms in more detail.
See the conservation initiatives and organisations working in each country →
Where to go next
Conservation is one strand of the wider Coral Triangle story. Return to the coraltriangle.org homepage for the full overview, including how this work is financed and communicated.