Invasive Fish Threaten Coimbatore’s Lakes: Urgent Action Needed
Coimbatore: The rejuvenation of the city’s lakes has transformed them into beautiful spots for residents and visitors to enjoy. However, there’s a troubling issue lurking beneath the surface. Many of these lakes are now overrun by invasive fish species, which pose a significant threat to the local aquatic ecosystem.
Recent reports indicate that invasive species such as African catfish, Tilapia, and common carp are now more prevalent than native fish species, leading to serious ecological concerns. Experts warn that these invasive fish can displace local species, disrupt food chains, and harm other aquatic life.
Adding to the problem, water pollution from sewage and heavy metals is contaminating lakes, which raises fears about toxic substances accumulating in the fish. Environmentalists are calling for urgent measures to control the spread of these invasive species and to better regulate fishing practices that have allowed exotic fish to thrive.
Despite a ban on selling African catfish, many vendors in the area continue to sell this species, highlighting significant enforcement weaknesses. “It’s crucial for the local government to take steps to revive the populations of native fish,” said an environmentalist.
During a recent visit to local lakes, it was noted that Tilapia made up the majority of fish for sale, with African catfish also being present. The Tamil Nadu Wetland Mission has identified several invasive species, including Tilapia and Mosquito fish, as major threats in the state’s wetlands.
R. Manikandan, founder of the Kovai Kulangal Pathukapu Amaipu organization, noted that many tanks connected to the Noyyal river are filled with these exotic species. “People aren’t aware of our local fish because of the dominance of invasive species. The government should conduct surveys of all water bodies to restore native fish populations,” he urged.
He reminisced about the crabs that used to inhabit Kurichi lake three decades ago, now absent due to predation from invasive fish. “These invasive species disrupt the food chain, leading to a decline in local organisms,” he said.
Researchers studying the situation have found that Tilapia, a non-native fish, predominates in local lakes and poses ecological challenges. “This fish can survive in low-oxygen conditions, making it highly resilient, but also a significant threat to our ecosystems,” one researcher pointed out.
Additionally, there are concerns regarding the introduction of Gambusia, or mosquito fish, intended to control mosquito populations. Research shows that this species is also invasive and could negatively impact local aquatic habitats.
S. Raja, an assistant professor in the zoology department at Kondunadu College of Arts and Science, emphasizes the need for stock assessments in lakes to understand the extent of invasive species dominance. “While there have been studies on both invasive and indigenous fish, a thorough stock assessment could provide vital information on the ecological balance within our water bodies,” he noted.
The growing presence of invasive fish species highlights the urgent need for action to protect Coimbatore’s lakes and preserve its aquatic biodiversity.
