Panaji: The growing presence of invasive species in Goa’s wetlands and water bodies is increasing, as fishermen in Cansaulim caught a mixed haul of exotic fish and fewer native species in a local pond on Sunday, according to a local report. In summer, fishing is traditionally undertaken in freshwater lakes and ponds, once rich with native species such as tigur, inzull, chikale, and other varieties in the past years.
Exotic Catch in Cansaulim
On Sunday, fishing at a privately-owned pond in Cuelim, Cansaulim, yielded a catch of invasive species including tilapia, sailfin armoured catfish, and African catfish. “There were some quantities of rohu, katla, and some native species like keri. But armoured sucker fish (pterygoplichthys), tilapia, snakeheads, and African catfish comprised a sizable part of the catch,” a local said.
Decline of Native Species
At Batim lake in Tiswadi taluka a week ago, the annual harvesting yielded a dominant catch of African catfish, a carnivore feeding on smaller fish, and Mozambique tilapia. Native species such as inzull, keri, and others once prized as delicacies have significantly depleted over the years in recent years. At Cansaulim, when fishermen cleaned the catch, exotic South American armoured fish was found discarded on the pond’s bank. “There is no market for it. This fish has been found in water bodies here for nearly two decades,” another resident said.
Ecological Impact of Armoured Fish
The ornamental fish, also called janitor fish and sagor by locals, is found in home aquariums. It is considered dangerous for smaller local fish species as it preys on them and also damages aquatic vegetation. Its overall impact on the local ecosystem remains to be studied, sources said. In March and April 2021, TOI reported about this non-native fish species after snake and domestic rescuer Stephen Johnson posted photographs of it in a catch at another pond in Cuelim. ICAR fisheries scientists identified it as the exotic aquarium fish species.
Expert Concerns
“The significant increase in populations of exotic fish species raises a concern about the competition native species face in a grim survival battle,” said Baban Ingole, a fisheries scientist and retired chief scientist at NIO-Goa. He had raised the issue as a serious concern for the local aquatic environment at a fish mela organised by the fisheries department. “A study is needed before this unwanted and dangerous species spreads to other areas,” Ingole added.
