It will take three years to bring the population of invasive blackchin tilapia under control, using genetic modification that will produce infertile offspring, according to the Department of Fisheries.
Male blackchin tilapia would be genetically modified so that they would mate and produce infertile fry, Bancha Sukkaew, the director-general of the department, said on Wednesday.
The department will release at least 250,000 genetically modified males over a period of 15 months, starting in December at the latest, he said. The method should substantially reduce the population of the invasive fish within three years, Mr Bancha said.
Apart from the long-term solution, the department is buying blackchin tilapia from the public at 15 baht per kilogramme, compared with market prices of seven to 10 baht, and promoting dishes and fishmeal made from the fish, he said. The department will also release predator fish to eat blackchin tilapia.
Two thousand blackchin tilapia were originally imported from Ghana in 2010 by CP Foods (CPF), 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.
Normally the import of the species is prohibited, but applications for research purposes are permitted on a case-by-case basis, said Mr Bancha.
CPF subsequently told the 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.
The Department of Fisheries early this year found large numbers of blackchin tilapia in Bangkok, Samut Prakan, Samut Sakhon, Samut Songkhram and Phetchaburi.
DNA tests conducted by the department confirmed that all the fish came from the same parent stock.
The fish are also present in large numbers in 11 other provinces: Chanthaburi, Rayong, Chachoengsao, Ratchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Songkhla, Nakhon Pathom and Nonthaburi.
According to local media reports, CPF has asserted that it disposed of all the blackchin tilapia properly in 2011.
In a document submitted to the House committee on science, technology, research and innovation, the company said it ended its blackchin tilapia research programme because of high mortality rates. The fish were euthanised using chlorine concentrate, their carcasses buried, and preserved samples submitted to the Department of Fisheries.
The company maintains it has no connections with the more recent outbreak, which reportedly began in 2017 and has worsened this year.
- Editorial: Really fishy business
Fisheries chief Bancha Sukkaew eats cooked blackchin tilapia during a press conference on Wednesday. (Photo: Nutthawat Wicheanbut)
