SAMUT PRAKAN: Fishermen in this province bordering the east of Bangkok have complained all their catches now consist of blackchin tilapia, while a fishery guru said they can reproduce at a rate of 1 million babies per day in Thailand.
Fishermen in tambon Khlong Dan of Bang Bo district said the alien fish species was the only kind of fish they could catch in local waterways and other species which used to be ubiquitous, such as other kinds of tilapia, had virtually disappeared.
Sitthikorn Ekwong, 21, cast his net in Khlong Dan canal for the eyes of reporters on Saturday afternoon – and blackchin tilapia were clearly all he caught.
An examination of his catch revealed the females had eggs inside their bodies while the males were holding germinated eggs in their mouths.
Blackchin tilapia
Local resident Pisamon Srisin, 75, said she started to see blackchin tilapia in tambon Khlong Dan last month. She can now catch no other kind of fish. She said blackchin tilapia were edible but their flesh was hard – not as soft as indigenous fish.
Thanapote Songkran, Moo 6 village headman in tambon Khlong Da, said he was seriously concerned about the growing population of blackchin tilapia because they bred very fast and ate all other small water animals and water plants. He urged relevant organisations to control the species.
Thanaporn Jiansuk, president of the Khlong Dan Fishery Association, said blackchin tilapia bred very fast as it took only 22 days from the egg-laying stage to hatching. As many as 99% of their eggs hatched, she said.
The fish could repeat their reproduction cycle right after laying eggs, without any break, she said.
According to Ms Thanaporn, the intestine of a blackchin tilapia is four times longer than the 20cm-length of its body. They eat every hour and statistics suggested that the fish could reproduce 1 million babies a day throughout the country.
Without a quick solution, blackchin tilapia might increase their population at an uncontrollable rate and destroy ecosystems, she said.
Two thousand blackchin tilapia were originally imported from Ghana in 2010 by CP Foods, part of the Charoen Pokphand agribusiness conglomerate, according to Isra News Agency. The company had a permit to study the fish for breeding at its research centre in Samut Songkhram province.
The company subsequently told the fisheries department that the fish had died within three weeks of being brought to Thailand and had been buried. But they later started showing up in local waterways and as their population grew, native fish species started decreasing in number.