Chennai: The state government has launched a campaign to control the spread of invasive African-origin Tilapia in Adyar Creek, aiming to protect local fish species and restore ecological balance. Originally introduced to Tamil Nadu in the 1950s as an affordable protein source, Tilapia quickly established itself in the state’s water bodies due to its ability to thrive in polluted environments with low oxygen levels.
Tilapia’s dominance is largely due to its mouthbrooding reproduction strategy, where eggs are incubated in the parent’s mouth until hatching. This, along with its aggressive behaviour and habit of preying on larvae of native fish, has caused a decline in indigenous species. The introduction of Genetically Improved Farmed Tilapia (GIFT) in the early 2000s worsened the situation, as this variety spread even more rapidly.
To combat the issue, the Chennai River Restoration Trust (CRRT) initiated a targeted effort at Adyar Creek, a 358-acre area, using nets to capture adult Tilapia and reduce their population. An increase in salinity levels earlier this year also triggered a significant Tilapia die-off, initially misinterpreted as a pollution event. The CRRT later clarified the cause in a report to the National Green Tribunal (NGT), which had taken independent notice of the incident near Kotturpuram Bridge.
Following four months of culling efforts, the return of around 40 native species has been observed, including pacific tarpon (peri meen), milkfish (pokaan), and flatfish (padugai meen).
While this strategy has shown promise in smaller water bodies, experts caution that controlling invasive species in larger ecosystems is more challenging. They emphasize the need for a comprehensive policy to address invasive fish such as Tilapia, suckerfish, and catfish. With the shrinking number of smaller water bodies due to urbanization, pollution threatening native fish populations, and insufficient upkeep of larger lakes, experts advocate for an integrated management approach.
In addition to policy development, specialists highlight the importance of conducting detailed surveys of native fish species. Such research is crucial not only for conservation efforts but also for fostering awareness among future generations about the region’s aquatic biodiversity.
Source: Times of India