Invasive tilapia devour farmed fish and shrimp; fishermen seek compensation from CP Group
On 4 February, Thailand’s Ministry of Agriculture and Cooperatives announced the successful breeding of a genetically modified strain of Blackchin tilapia. These modified tetraploid tilapia produce sterile offspring when mated with naturally occurring diploid tilapia. The government hopes this will curb the spread of the African invasive species and reverse the resulting ecological damage.
Currently, Blackchin tilapia have plagued as many as 19 Thai provinces, devastating local aquatic ecosystems. Consequently, environmental scientists have warned that the proliferation of the Blackchin tilapia is “the most severe ecological disaster in Thailand’s history”.
This news has sparked concern among the public and the scientific community: the release of chromosome-modified experimental animals into the wild could have unpredictable effects on the environment and related species, suggesting a more cautious approach is required.
The Thai government’s strategy feels somewhat like “fighting fire with fire”: attempting to introduce modified, sterile tilapia into the wild to defeat an invasive alien species. It is worth noting that the original arrival of Blackchin tilapia in Thailand from Africa was also the result of a failed experiment.
According to Thai media, CP Foods, a subsidiary of the CP Group, imported 2,000 Blackchin tilapia from Ghana in 2010 for breeding trials at its fish farm in Ampawa, Samut Songkhram Province. This is the only recorded instance of the species being introduced to Thailand. At the time, the experiment aimed to improve the disease resistance of commercial Nile tilapia and test the Blackchin tilapia’s adaptability to saltwater to meet the demands of expanding industrialised aquaculture.
Although CP claimed the experiment failed and the project was quickly terminated, Blackchin tilapia began appearing around the experimental farm. Soon, traces of the fish were found across multiple provinces and even within the canals of Bangkok.
On 13 January 2025, over 200 representatives from 19 Thai provinces gathered outside the CP Group headquarters in Bangkok. Representing fishermen whose livelihoods had been devastated by the tilapia infestation, they accused the CP Group and its subsidiary, CP Foods. They told the media that the invasion had caused the local ecosystem to collapse over the past decade, threatening the livelihoods of fishermen; they demanded government action and compensation from the CP Group.
I. The Tilapia Invasion
This extraordinary adaptability and reproductive capacity mean that once it enters a non-native environment, it can instantly become an invasive species that destroys local ecosystems. In Southern China, tilapia are currently among the most significant invasive fish. Close relatives of the Blackchin tilapia, such as the Nile tilapia and Blue tilapia, were introduced to China in 1978 and subsequently escaped into natural waters. Research indicates that in some sections of the Pearl River Basin, the tilapia population has even exceeded the combined total of all other fish species.
A similar scenario has unfolded in Thailand. A statement submitted by the protesters to the Thai Prime Minister read: “The Blackchin tilapia have consumed all the food in ponds and natural canals; they eat the plankton and young aquatic animals. Consequently, shrimp, fish, molluscs, and crabs in ponds, as well as other aquatic life in natural water sources, have been devastatingly destroyed.”
The destruction of the natural ecosystem has hit individual fishermen engaged in traditional fishing and aquaculture the hardest.
Mongabay, an independent media outlet, quoted Wanlop Kunjeng, a former shrimp farmer from Samut Songkhram Province, who said that ten years ago, his shrimp ponds were destroyed by Blackchin tilapia. This forced him to switch to farming sea bass—a species large enough to withstand tilapia attacks. However, this came at the cost of higher upfront investment and a longer return cycle compared to shrimp farming.
Lin Zhiguang, Southeast Asia head of GRAIN (an organisation supporting small-scale farmers), told Mongabay that Blackchin tilapia have “destroyed traditional shrimp farming systems in coastal areas that did not require commercial feed, forcing small-scale farmers to adopt intensive, closed systems that rely on feed, chemicals, and antibiotics provided by agribusinesses”.
Furthermore, unlike other commercial tilapia varieties, Mongabay cited an environmental scientist from Khon Kaen University who noted that the meat of the Blackchin tilapia is less palatable than that of other commercial tilapia, meaning there is little local demand for them even when fishermen manage to catch them.
According to data from the Royal Thai Lawyers Association, fishermen have suffered direct economic losses as high as 2.486 billion baht (approximately 533 million yuan), while additional losses to society and the ecosystem exceed hundreds of billions of baht—and even these estimates are likely conservative. “Many are burdened with debt or have lost their land; some have even committed suicide, particularly in Samut Songkhram Province.”
In July 2024, the Thai government added the control of the Blackchin tilapia infestation to the national agenda, approving a budget of 450 million baht (approximately 97 million yuan) to encourage their capture, offering up to 15 baht (approximately 3 yuan) per kilogram.
However, this government buy-back scheme lasted less than four months, and the purchase price later dropped to 3–4 baht (approximately 0.6–0.8 yuan) per kilogram. At this rate, fishermen would need to catch a tonne every day to make a profit—a daunting task. Many fishermen stopped fishing once the government ceased its buy-back programme.
II. What responsibility should CP Group bear?
In 2017, affected community fishermen and farmers filed a complaint with the Thai National Human Rights Commission, seeking remedies and government intervention.
CP Foods denied any responsibility for the environmental crisis. They claimed that while the company did import Blackchin tilapia from Ghana for research in December 2010, the fish became weak and died a month later, leading to the project’s termination. The company stated that all fish were subsequently disposed of using approved methods, and samples and documentation were sent to the Department of Fisheries.
However, the committee handling the complaint reported that CP Foods had failed to comply with the biosecurity regulations set by the Department of Fisheries. They noted, “The company failed to report the test results and deaths of the Blackchin tilapia in writing, which violates the standards and conditions for permits regarding non-native aquatic species”.
Despite multiple subsequent investigations by the Thai government, the origin of the Blackchin tilapia has yet to be officially determined, leaving the affected fishermen unable to hold CP Foods accountable or claim compensation.
In July 2024, the BioThai Foundation, a non-profit organisation focused on biodiversity and sustainable agriculture in Thailand, announced it would seek corporate accountability through legal means. Withoon Lienchamroon, a director of the foundation, told the Bangkok Post: “The government has been spending taxpayers’ money to solve this problem, which is unfair to us. We need to ensure that those responsible are held legally accountable.”
A rally on 13 January reaffirmed the demand for compensation through litigation and urged the government to identify the party responsible for the ecological disaster. An open letter released at the rally noted that CP Foods’ profits in the third quarter of 2024 alone reached 7.3 billion baht (approximately 1.56 billion yuan). They argued that as a listed company, CP Group “should redistribute a portion of these profits to society to address issues such as the infestation of blackchin tilapia”.
III. Will there be a response?
Even if everything proceeds smoothly, the process of ecological restoration is far more arduous and prolonged than the pursuit of accountability and compensation; the blackchin tilapia itself is unlikely to be “eradicated” as hoped. A Thai fisheries expert told the BBC: “The problem with invasive species is that once they have established themselves, they are very difficult to eliminate.”
HaRDstories, a Thai independent media outlet, cited a senior aquatic ecology expert from the Mekong River Commission warning that without systematic action to resolve the issue, the Mekong Delta and Singapore could also be threatened within the next five years.
It is clear that this long struggle involving humans and nature over the blackchin tilapia is far from over.
In a statement of support, MASIPAG wrote that it was “corporate greed and a disregard for ecology and community welfare” that fuelled this environmental disaster. Can the short-sighted learn a lesson from the fact that a small number of invasive organisms can have such profound and irreversible effects? Without mechanisms to ensure perpetrators compensate for losses and restore the environment, and without cautious management of similar breeding experiments, environmental disasters born of economic interest will remain inevitable in the future.
❸ The Cabinet must establish a national committee and provincial task forces to eradicate the blackchin tilapia, restore the ecosystem, and recover the livelihoods of farmers and other affected parties. The committee and task forces must aim for the complete eradication of blackchin tilapia by 2026 and be allocated a corresponding budget.
❹ Once the investigation is complete and the responsible party identified, the government must bring legal charges and initiate litigation proceedings. The negligent party must provide compensation and pay for losses, ensuring that the cost of restoration does not fall upon the Thai taxpayer.
References
https://bkktribune.com/cpf-accused-of-breeding-blackchin-fish-since-first-fish-import/
https://bkktribune.com/series-of-legal-action-taken-in-blackchin-tilapia-fish-invasion-case/
Editor: Wang Hao