Cyanide that is sprayed or dumped on reefs can damage and kill corals. In addition, fishers often break corals when attempting to extract the stunned fish, causing further damage to the coral reef ecosystem. Unfortunately, about one-third to one-half of fish collected using this method die soon after they are harvested, ref making this a particularly destructive method of harvest.
Some types of fishing gear, including gill nets and beach seines, can also damage reef ecosystems. These types of fishing gear drag along the ocean floor and capture or flatten non-targeted juvenile species and corals in their path. Additionally, scuba and hookah diving have opened up deeper areas to fishers of sea cucumbers, pearl oysters, lobsters, octopus, fishes, seashells, and corals. The researchers counted more than explosions in 30 days, from the Kenya-Tanzania border down to Mozambique.
Now new video footage for National Geographic by reporters Sophie Tremblay and Willy Lowry captures some of the blasts in real time. Why do they do it? Making a bomb is cheaper and vastly more productive than sticking with traditional fishing methods such as basket traps and hook and line.
Dynamite is also easier to find nowadays. A boom in mining and construction in Tanzania has made it less challenging for people to get their hands on explosives. But the practice has disastrous consequences. Off the coast of Dar es Salaam, fishermen aim for lucrative tuna, Tremblay says.
But the blasts destroy not only their targets but entire coral reefs, which support fish, crabs, and other species and play a crucial role in controlling carbon dioxide levels in the ocean. Aside from the environmental impact, dynamite fishing threatens the livelihood of legitimate fishermen, as well as the economy as a whole.
Check out the film to learn more about the dangerous fishing tactic and see blast fishermen in action. Send tips, feedback, and story ideas to ngwildlife natgeo. The frequently improvised nature of the explosives used also means danger for the fishermen as well, with accidents and injuries common.
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. The underwater shockwaves produced by the explosion cause the fish's swim bladder to rupture, killing or stunning them.
A small number of fish float to the surface, but most sink to the sea floor. The explosion indiscriminately kills 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. Areas around the blast are reduced to lifeless rubble and do not recover very fast because coral larvae are unable to find places to settle on unfavourable substrate such as unconsolidated coral rubble or dead coral covered with algae.
Without the coral reef, fish populations do not easily recover. Although banned in Malaysia under the Fisheries Act, both fish bombing and cyanide fishing are widespread in Sabah. Given the illegal or undocumented status of many fish bombers, it is difficult to find ways to involve them in government projects promoting alternative livelihoods such as seaweed farming and aquaculture. Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big.
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