Jakarta is currently engaged in a massive effort to purge its waterways of an invasive fish species that has turned a pollution crisis into an ecological and public health emergency. The fish, known locally as sapu-sapu, are thriving in heavily contaminated rivers that one cleaning organizer described as being “like dark black” and smelling like “rotten eggs.”
A Crisis Born from Aquariums
Originally brought to Indonesia from South America to clean algae from aquariums, sapu-sapu were introduced into local waterways after being dumped by owners. Once in the wild, the species multiplied rapidly, pushing out native fish and dominating the ecosystem.
The fish are particularly hardy and lack the natural predators they have in the Amazon. They can grow to approximately 20 inches and produce thousands of eggs annually, allowing them to quickly overwhelm waterways already under environmental pressure.
Mass Removal Efforts
In response to the infestation, Jakarta has launched a broad removal campaign. This initiative involves a coalition of residents, soldiers, fisheries staff and sanitation crews working to kill the destructive fish.
The scale of the problem is evident in South Jakarta, where workers hauled roughly 5.8 tons of sapu-sapu from the rivers in just two weeks. While the invasive fish are killed and buried, any native fish caught in the nets are released back into the water.
Environmental and Structural Damage
Beyond displacing native wildlife, the sapu-sapu are actively damaging the city’s infrastructure. The fish dig holes in riverbanks to lay their eggs, a process that can weaken and cause the collapse of river walls.
Public Health Risks
There are growing concerns regarding the consumption of these fish. Mayor Muhammad Anwar explained, “In some places, it is consumed as a dangerous snack called siomay (steamed fish dumpling) and pempek (fish cakes).”
Local warnings suggest the fish are not fit for human consumption because they may contain contaminants and heavy metals absorbed from the polluted water.
The Role of Pollution
The success of the sapu-sapu is closely linked to the state of Indonesia’s waterways. Data from the United Nations Environment Programme indicates that over half of the country’s rivers are heavily polluted.
only 7.4% of municipal wastewater is safely collected and treated. Local advocates suggest that while removal campaigns provide immediate relief, cleaning up river pollution may be the only way to effectively reduce the waste that the invasive fish depend on.
Future Outlook
Given the current environmental conditions, the removal of sapu-sapu may only serve as a short-term fix. A more sustainable outcome could depend on systemic improvements to wastewater treatment to make the rivers less hospitable to the invasive species.
Frequently Asked Questions
Where did the sapu-sapu fish originate?
They were brought to Indonesia from South America, originally intended for use in aquariums to clean algae.
Why is eating sapu-sapu considered dangerous?
Locals warn that the fish may contain heavy metals and other contaminants due to the heavily polluted waterways in which they live.
How do these fish affect the physical structure of the rivers?
Sapu-sapu dig holes in the riverbanks to lay their eggs, which can cause river walls to weaken and collapse.
Do you believe urban pollution is the primary driver of invasive species outbreaks in major cities?
