African catfish, Clarias gariepinus – a major threat to native fish species in Western Ghats Rivers

African Mushi, that is what the farmers in Kerala called that beefy fish, which guaranteed profit for meager investment and care. It ate anything from wastes from slaughter houses and was able to live in any type of water qualities. Moreover, the fish grew faster and bulkier. Within months, a harvest will fetch you kilograms of fish meat from an average fish pond.

Clarias gariepinus

But the after effects were horrid. Recent research reports indicate that the fish has started appearing in fish catches from rivers and lakes in Kerala. Multiple reports suggest that this fish is now commonly caught by fishermen in the lower reaches of Periyar River in Kerala, which is known to house fresh water fresh species only found in Western Ghats Rivers.  Similar reports also indicate that the fish is present in the commercial catches from the Periyar Lake also.  

The writing on the wall is clear. The fish has escaped from fish farms which were connected to natural water bodies and have proliferated in the Western Ghats Rivers and other water bodies in the area. The species is known to devour and sweep away native fish species and other aquatic organisms locally.

The issue is not restricted to rivers in Kerala. It is reported that this invasive fish has also reached the Indrayani River in the southern Deccan Plateau eco-region. It presently raises serious threat to the only existing population of rare Sisorid catfish Glyptothorax poonaensis found in India. Sisorid catfish is listed as endangered by IUCN.

According to IUCN, the southernmost region of the Western Ghats Rivers house more endemic and lesser known fishes in the region. Unfortunately, the devouring African Cat fish has infected the same parts.

Abundance of Globally Threatened fish species 

in Western Ghats Rivers. It can be seen that they are 

more found in the Southern region.

Experts have also expressed concern over the impact of the presence of this African catfishes on lesser known subterranean fishes in Western Ghats. Ichthyologists were able to record just six to seven species from these enigmatic fishes which live in a subsurface ecosystem found under the laterite foot hills of Western Ghats. The chances of the African Cat fish eliminating many of these enigmatic creatures even before the researchers are able to spot and record them are not rare.

There is an urgent need to restrict the aquarium trade and unregulated fish farming. Educating buyers and farmers as well as formulating a proper policy for the management of invasive species are exigencies in this regard.