Back to homepage

Threats to Biodiversity

There are numerous threats to the biodiversity of Komodo National Park including human population pressure, tourism, the introduction of exotic species and poaching.  However, the most potent threat lies in the destructive fishing practices that take place in and around the Park. These practices destroy the coastal environment at great economic costs in terms of coastal protection, fisheries and tourism. 

To learn more about destructive fishing practices and the trade that supports them please click on one of the following topics.

Blast fishing
Cyanide Fishing
Reef Gleaning
Fish traps (bubu), Hook and Line and Gillnets
Over-harvesting
Live Reef Fish Trade

BLAST FISHING :  

Fish bombs are mostly made with artificial (chemical) fertilizers such as ammonium- and potassium nitrate (NH₄NO₃; KNO₃), which is mixed with kerosene in a bottle.  Blast fishers hunt specifically for schooling reef fish, so that only a few bombs will assure a relatively large catch. After the charge explodes, diving fishers enter the water to collect the fish, which have been killed or stunned by the shock-wave from the explosion.  The size of the coral area destroyed by a single blast is dependent upon the size of the bomb and the position of the explosion relative to the coral reef. A beer bottle bomb will shatter an area of stony corals approximately 5 m in diameter.

Many blast fishing operations use "hookah" compressors to collect their catch from the reef. Blast fishing is considered one of the most destructive anthropogenic threats to coral reef ecosystems. It has been estimated that the economic costs of this practice are US$100,000 per km² on average in terms of coastal protection, fisheries and tourism.  Moreover, there has been a loss of around 85,000km² of coral reefs creating a total loss of  US$8.5 billion.  

CYANIDE FISHING :

Cyanide solutions are used extensively to catch live reef fish for consumption and ornamental purposes. The concentrations of dissolved poison are not meant to kill but only to tranquilize the target fish, which facilitates their capture. The live food-fish trade concentrates on the catch of groupers and Napoleon wrasse. The aquarium fish trade concentrates on a much wider variety of species of colorful reef fishes. Live spiny lobsters, are also caught with cyanide. Cyanide fishing is done by divers, using "hookah" compressors and hoses to supply air. A diver on a "hookah" compressor-hose descends 10-40 meters until he spots a target fish. He chases the fish into a crevice in the reef and then squirts cyanide from a plastic bottle into the hole. As the fish begins to weaken, the diver breaks away the coral around the hole, reaches in, grabs the fish, and slowly escorts it to the surface. The cyanide fishery for aquarium fish destroys large areas of corals, which are broken down after an area has been sprayed with cyanide and the target fishes have fled in between the corals. The use of hookah compressors is a key factor in cyanide fishing practices.

REEF GLEANING :

The fishery for abalone (mata tuju) has destroyed large areas of coral reefs in recent years. Many fishermen are digging through the reefs, using compressors and steel bar tools (the method is called 'meting'), in search of abalone and other marine invertebrates. The fishermen break down and turn over the corals (which are also trampled by them in the process) and leave behind them fields of near 100% dead coral rubble. Collecting invertebrates from reef flats is a traditional activity, which used to be focused on sea cucumber  and carried out during very low tides. The high price for abalone and the availability of dive gear and 'hookah' compressors changed this into a more serious activity in the early nineties and initiated an increase in the total applied effort.

FISH TRAPS (BUBU), HOOK & LINE AND GILLNETS :

The use of bamboo mesh traps) is widespread in Indonesian reef fisheries. The process of setting and retrieving the trap is responsible for extensive destruction on the reef. To hide the traps in the reef, divers break off live coral to cover them. Traps set by simply lowering the trap from boat side via a buoyed rope are responsible for even more serious reef damage. These traps are often heavily weighted, and can destroy entire stands of corals during their installation.

The main yield category from the Park is fish (almost 95%). These fish are mostly caught by gillnets, and by trolling and bottom hook and lines. Demersal trolling lines or 'kedo kedo' are wiping out the coral trout stocks. Bottom hook and lines catch all predators and bottom longlines are decimating the sharks and large groupers. Gillnets kill indiscriminately, including turtles, dugong, cetaceans, and all species of reef fish. The fish stocks of the Park are seriously threatened by the use of gillnets and bottom longlines.

OVER-HARVESTING :

The target fish species in the live reef fish trade commonly aggregate at specific sites to spawn. Groupers and Napoleon wrasse migrate many miles each season to these spawning sites. Spawning aggregation sites are extremely vulnerable since experienced fishers are skilled in locating them. Wiping out the fish on one aggregation site equals the elimination of top predators from several square miles of reef. Grouper and Napoleon wrasse spawning aggregation sites

Mangroves, seagrass, lontar palms, and other species have been over harvested in the past. Seagrass is collected for use as a food source and as an ingredient for cosmetics. There is a large external market for these products. Mangrove tress are used for fire wood. The palm trees are used to make furniture and buildings locally. The decrease in the seagrass population may lead to increased coral mortality and decreases in species dependent upon them for shelter and food.

This website is maintained by PT. Putri Naga Komodo, the implementing unit of Komodo Collaborative Management Initiative (KCMI).


Today: