The government has imposed a ban on farming of African catfish, an invasive species that is proliferating in waterbodies across the State, posing a threat to native aquatic species.
Experts, however, feel that the ban would have little effect unless the existing stocks are destroyed through selective culling.
The order banning catfish farming was based on a recommendation by the Fisheries Director. A study conducted by the government had found that the practice, widespread in Palakkad district, was posing a threat to several local varieties of fish and polluting waterbodies. MLAs from the district had repeatedly raised the demand to ban the species in the light of environmental impact.
Known locally as African Mushi, the African catfish (Clarias gariepinus) is a carnivorous species introduced in India without official sanction. A survey carried out by the University of Kerala and the Department of Environment and Climate Change last year reported that most reservoirs in Kerala were teeming with African catfish. The species was found to thrive well in the Kundala, Mattupetti, Anayirankal, Munnar head works, Shengulam, Ponmudi, Kallarkutty, and Lower Periyar dams and in all the tributaries of the Periyar river.
Native to Africa and the Middle East where it inhabits freshwater lakes, rivers, swamps, and urban sewage systems, the African catfish was introduced all over the world in the early 1980s for aquaculture. The voracious predator feeds on living and dead animal matter, including fish and invertebrates, and is known to attack small birds. Its ability to survive in shallow mud for long periods of time, high tolerance for poorly oxygenated water, and fast breeding give it an edge over other native species.
A. Biju Kumar of the Department of Aquatic Biology, University of Kerala, said it was imperative for the government to come out with an action plan for selective culling of the invasive species, considering its dominance in waterbodies across the State.
Despite a ban imposed by the Union government in 2013, clandestine farming of catfish continues to thrive in the eastern border villages of Palakkad. Many of the farms use chicken waste as feed, polluting water sources, and the environment.