Blast fishing was introduced in Southeast Asia post World War II, by American soldiers who threw grenades into bodies of water to yield a large cache of fish, a technique which is used  during the modern day to produce fish as a food resource in local markets. Dynamite is often used but any explosive will perform the task effectively, even improvised devices which utilize an explosive chemical within a glass drinking bottle with an improvised wick lit by a cigarette. Cyanide fishing is an ecologically destructive method of catching fish in which a diver takes bottled cyanide and pumps it into reef areas where fish reside, stunning the fish and making them easier to catch, so that they can be extracted for the pet and live fish trades. These techniques result in coral reefs losing their color and ultimately dying, eliminating a major food source for marine life within the region. Both methods are extremely damaging to the ecosystem and left unchecked, can decimate entire ecosystems within a few short years. Portions of and entire coral reefs which have slowly built over thousands of years can be destroyed in a matter of seconds by using either of these harmful techniques. Fortunately, both methods of fishing are illegal in most of Southeast Asia