One type of farmed fish, with the common name tilapia, is now breeding abundantly in rivers and creeks, putting wild species at risk, U Aung Myo Chit, founder of a local NGO Grow Back for Posterity, told The Myanmar Times. Myanmar is subject to regular flooding, which leads to farmed fish escaping into the wild. The tilapia are often caught in the Ayeyarwady River, U Aung Myo Chit said. The residue of chemicals and foods used in fish farming are also harmful to wild species, he added. Tilapia’s proliferation comes at the expense of wild fish, who find food sources depleted. Farmed fish species can also infect wild species with diseases against which they have no defence, he said. The foods and chemicals also make farmed fish more resilient to pollution, and so when rivers are contaminated it is the farmed fish that survive, U Aung Myo Chit said. Oceanographer Daw Toe Nanda Tin said a more systematic approach to farming tilapia would bring clear benefits, and suggested several measures. To control the proliferation of tilapia you can only breed males in the farm, she said, adding that if the fish were to be released from the farm they would be unable to reproduce. As the fish grow to sufficient size to eat within four to six months, farming could be confined to winter and summer avoiding the rainy season and floods, she added. But because farmed fish species are chosen for their fast growth, this also makes addressing the issue even more important. It’s not just tilapia, Daw Toe Nanda Tin said. Other [farmed] fish species need to be controlled or wild species could end up being eaten or being pushed to other regions. Environmental exports say there are no laws or regulation for preventing the spread of farmed fish outside of the farms, or any system to control them once this happens. But Myanmar is not the first country to tackle a farmed fish outbreak. The US and Australia faced similar problems with carp and roho labeo, and had to design a plan to catch them, said U Aung Myo Chit. But there hasn’t been much research on aquatic biodiversity in Myanmar. We can’t say how many fish species inhabit the Ayeyarwady River, so we can’t say how many species have gone extinct. In a recent conversation with fisherman on the Ayeyarwady River, it transpired that a species of barbus could not longer be found, he said. But even that is unsure because different regions have different names for the same fish, he said.
2016 The Myanmar Times.