In Southeast Asia, blast fishing was occasionally practiced during the colonial era in the late 19th century, before nation states in Southeast Asia were formed. Evidence shows the use of dynamite to catch fish in Southeast Asia continued in the 1900s. For example, from 1907 to 1910, the Philippine expedition of the USA Bureau of Fisheries used explosives to gather underwater samples, including fish.
There is also evidence that in the 1930s the Japanese used blast fishing in Southeast Asia waters to feed its advancing preparation effort to establish and occupy key areas. During the 1940’s, blast fishing was widely practiced among Filipino fishermen who paid a high fee to the municipal authorities. After that, blast fishing spread throughout South Asian waters, including China, Indonesia and Malaysia. Since the end of the Second World War, coral reefs of the Indo Pacific and especially the South China Sea have been subjected to dynamite or blast fishing. More recently, the practice has continued, shifting from dynamite to ANFO fertilizer bombs.
Fishermen put a fertilizer-petroleum oil mix into a bottle and include a small detonator cap to make a bomb. The bombs are usually on 5-second fuses and are dropped into the center of an area judged to have many fish. After the bomb has exploded, the fishers use dip-nets or fry nets to collect the stunned and dying fish, either from the boat or underwater. The fishers do not blast at random but choose the site carefully for a maximum catch.
The short term gain from blast fishing is the attraction for fishermen. Economic models show that blast fishing is initially four times more efficient than non- destructive fishing methods. However, after 20 years, income declines to one fifth of what would have been available by sustainable methods. For example, in North Sulawesi, Indonesia, net annual income per fisherman dropped from US$6,450 to less than US$550.
Although many blast fishers understand that their activities destroy fish habitat, most are not aware that their activities threaten their own livelihood. They know that their reefs have deteriorated, but most are convinced that there are still better reefs further afield. For some, lower yield from traditional fishing methods are forcing them to turn to blast fishing, even though it exposes them to many dangers.
One problem impeding more effective action on fish bombing is lack of data. The coasts are vast and we acknowledge that it is almost impossible to patrol all areas. But with a more consistent dataset, it is possible to pin point the “hot spots” where blast fishermen conduct their activities and possibly when they are most likely to do so.