Blast fishing

Dead fish and damaged coral as the result of blast fishing.

Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat (such as coral reefs) that supports the fish.^[1] The frequently improvised nature of the explosives used also means danger for the fishermen as well, with accidents and injuries.

Although outlawed, the practice remains widespread in Southeast Asia, as well as in the Aegean Sea, and coastal Africa. In the Philippines, where the practice has been well-documented^[2], blast fishing was known prior to World War I, as this activity is mentioned by Ernst Jünger in his book Storm of Steel.^[3] One 1999 report estimated that some 70,000 fishermen (12% of the Philippines' total fishermen) engaged in the practice.^[4]

Extensive hard-to-patrol coastlines, the lure of lucrative, easy catches, and in some cases outright apathy or corruption on the part of local officials make enforcement of blast fishing bans an ongoing challenge for authorities.^[5]

Commercial dynamite or, more commonly, homemade bombs constructed using a glass bottle with layers of powdered potassium nitrate and pebbles or an ammonium nitrate and kerosene mixture are often employed. Such devices, though, may explode prematurely without warning, and have been known to injure or kill the person using them, or innocent bystanders.^[1]

Underwater shock waves produced by the explosion stun the fish and cause their swim bladders to rupture. This rupturing causes an abrupt loss of buoyancy; a small number of fish float to the surface, but most sink to the sea floor. The explosions indiscriminately kill large numbers of fish and other marine organisms in the vicinity and can damage or destroy the physical environment, including extensive damage to coral reefs.^[6][7]

Impact on coral reefs

Main article: Coral Reef

Researchers believe that destructive fishing practices like blast fishing to be the biggest threat to the coral reef ecosystems. Blown up coral reefs are no more than rubble fields. The long-term impact associated with blast fishing is that there is no natural recovery of the reefs. Coral reefs are less likely to recover from constant disturbance such as blast fishing than from small disturbance that does not change the physical environment. Blast fishing destroys the calcium carbonate coral skeletons and is one of the continual disruptions of coral reefs.^[8] In the Indo-Pacific, the practice of blast fishing is a main cause of coral reef degradation. As a result, weakened rubble fields are formed and fish habitat is reduced.

The damaged coral reefs from blast fishing lead to instant declines in fish species wealth and quantity.^[9] Explosives used in blast fishing not only kill fish but also destroy coral skeletons, creating unbalanced coral rubble. The elimination of the fish also eliminates the resilience of the coral reefs to climate change, further hindering their recovery. Single blasts cause reefs to recover over 5–10 years, while widespread blasting, as often practiced, transforms these biodiverse ecosystems into continuous unstable rubble.^[10]

Strategies to control blast fishing

Community-based Enforcement

In Tanzania, one of the few methods to help manage blast fishing is a joint approach between fisheries officers and village committees. Working together, they help the enforcement agencies recognize offenders by patrolling the sea as well as providing information collected in the local villages. As a result, this has assisted the enforcement agencies to reduce the occurrence of fish blasting from an average of 8 per day to zero. It has also provided sustainable funding to continue the efficient patrols, a certified planning institution, and suitable training and information to prosecutors and judges.

Similar patrols employed in Indonesia and Philippines have reduced the amount of blast fishing occurrences there. Based on dialogue with stakeholder groups in Southeast Asia and people of Tanzania and Philippines, it is evident that firmer enforcement is an effective strategy in managing blast fishing. Many countries have laws regarding blast fishing, but they are not fully implemented. Effective management of Marine Protected Areas (MPAs) is key in the patrolling of illegal fishing areas.^[11]

Blast Detection System

This method involves a triangulation system of hydrophones one meter apart that is capable of detecting blast events and at the same time eliminating other sources of underwater noise. The goal of the system is to improve and assist the effectiveness of fisheries patrol. Based on tests performed in Malaysia from 7 to 15 July 2002, a total of 13 blasts were recorded with a directional uncertainty of 0.2°. An electronic compass would limit the bearing uncertainty to 0.2° while correcting for the local magnetic effects of ferrous metals, therefore making sure the precision of the system is high.

Similar triangulation systems of hydrophones can potentially locate single blast events within 30 m at a range of 10 km. The detector system can be mounted on a patrol boat to help locate a probable range of blasts. Two or more patrol boats would permit accurate triangulation of blast events. Such a method is also beneficial to enforcement agencies, as it offers stronger evidence to support convictions related to blast fishing.^[11]

Countries

Tanzania

In northern Tanzania, blast fishing, which is illegal, has re-emerged in recent years as a key danger to its coral reefs. This has occurred even though major institutions like local communities and the district government have been put in place for enhanced fisheries management. The damage of blast fishing in the area has contributed to unstable coral reefs, discouragement of tourism investors, and a threat to the habitat of coelacanths in the region. Other impacts of blast fishing in the area include reports that citizens have died or lost limbs due to the blasting. The northern part of the country has many beautiful beaches and uninhabited islands. However, many investors feel and tourists are discouraged due to the fish blasting.^[12]

In Tanzania, coral reefs are essential for both ecological and socio-economic reasons. They are full of fish, lobsters, prawns, crabs, octopuses, mollusks, and sea cucumbers. In addition, coral reefs are one of the major tourist attractions in Tanzania. The coastal tourism provides a living for the people as well as foreign currency for the country. However, there has been an increase in the people living along the coast which has led to a large demand for fisheries. It has led to overexploitation and destructive fishing practices. Blast fishing has been practised in Tanzania since the 1960s. It was during the 1980s and 1990s that blast fishing was at its peak in Tanzania. For example, in Mnazi bay, Mtwara, 441 blasts were recorded in two months in 1996, and 100 blasts were witnessed through one 6 hour period in Mpovi reef.^[13]

Indonesia

Blast fishing in Indonesia has been around for over 50 years. The use of bombs made with kerosene and fertilizer is very popular in the region. In the market in the city of Makassar, an estimated 10 to 40 percent of the fish are caught in this manner. The local fishermen find the technique to be easier and more productive than traditional methods. The goal for the country has been to implement stricter polices and fisheries management programs to limit the killing of the fish as well as the destruction to the marine ecosystem. Forty years ago, blast fishing was practiced with dynamite which was in plentiful supply after World War II. Today, fishermen mostly use homemade bombs that are made from bottles filled with an explosive mixture; weights are also added to make the bottle sink faster underwater. After the bomb explodes, the fish killed or stunned by the shock wave from the explosion are collected.^[14]

See also

• Environmental effects of fishing
• Fish kill
• Marine conservation

References

1. ^ ^{a b} http://www.eoearth.org/article/Coral_degradation_through_destructive_fishing_practices Coral degradation through destructive fishing practices
2. ^ http://www.tracc.00server.com/Fisheries/blast_fishing/economics.html Blast Fishing
3. ^ Jünger, Ernst (2004 ed) Storm of Steel Penguin Classics. Page 104. Translated by Michael Hofmann. ISBN 9780142437902
4. ^ http://www.oneocean.org/overseas/may99/a_closer_look_at_blast_fishing_in_the_philippines.html A Closer Look at Blast Fishing in the Philippines
5. ^ http://www.spc.int/Coastfish/News/lrf/8/LRF8-05-Pet.htm Destructive fishing mini symposium at the 9th International Coral Reef Symposium, Bali, Indonesia
6. ^ http://stigmes.gr/br/brpages/articles/dinambr.htm Explosions In The Cretan Sea: The scourge of illegal fishing.
7. ^ http://www.ecoreefs.com/ Blast Fishing and Coral Reef Damage
8. ^ Fox, H. E., Pet, J. S., Dahuri, R., & Caldwell, R. L. (2003). Recovery in rubble fields: long-term impacts of blast fishing. Marine Pollution Bulletin, 46(8), 1024-1031. Retrieved October 25, 2009, from ScienceDirect.
9. ^ Raymundo, L. J., Maypa, A. P., Gomez, E. D., & Cadiz, P. (2007). Can dynamite-blasted reefs recover? A novel, low-tech approach to stimulating natural recovery in fish and coral populations. Marine Pollution Bulletin, 54(7), 1009-1019. Retrieved October 25, 2009, from ScienceDirect.
10. ^ Fox, H. E., & Caldwell, R. L. (2006). Recovery From Blast Fishing On Coral Reefs: A Tale of Two Scales. Ecological Applications, 16(5), 1631-1635. Retrieved October 25, 2009, from EBSCOhost.
11. ^ ^{a b} Woodman, G. H., Wilson, S. C., Li, V. Y., & Renneberg, R. (2004). A direction-sensitive underwater blast detector and its application for managing blast fishing. Marine Pollution Bulletin, 49(11), 964-973. Retrieved October 25, 2009, from ScienceDirect.
12. ^ Wells, S. (2009). Dynamite fishing in northern Tanzania – pervasive, problematic and yet preventable. Marine Pollution Bulletin, 58(1), 20-23. Retrieved October 25, 2009, from ScienceDirect.
13. ^ Wagner, G. M. (2004). Coral Reefs and Their Management in Tanzania. Western Indian Ocean, 3(2), 227-243. Retrieved October 25, 2009
14. ^ Pet-Soede, L., & Erdmann, M. V. (1998). Blast Fishing in Southwest Sulawesi, Indonesia. Naga, The ICLARM Quarterly, 1-6. Retrieved October 25, 2009

Further reading

• Verheij E., Makoloweka S., Kalombo H. Collaborative coastal management improves coral reefs and fisheries in Tanga, Tanzania (2004) Ocean and Coastal Management, 47 (7-8 SPEC. ISS.), pp. 309-320.
• Martin, G. (2002, May 30). The depths of destruction Dynamite fishing ravages Philippines' precious coral reefs. Retrieved October 25, 2009, from http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2002/05/30/MN232485.DTL
• Bell J.D., Ratner B.D., Stobutzki I., Oliver J.Addressing the coral reef crisis in developing countries (2006) Ocean and Coastal Management, 49 (12), pp. 976-985.

External links

• Coarse & Even Coarser Fishing
• Sustainable Fishing
• International Working Group Draft Report
• Exploitive Fishing
• Blast Fishing