Event Inauguration at the hands of Mr. Sanjayan Kumar, Dy. Dir., PTR
(L-R) Krishna Kumar, Sanjayan Kumar, Sanjay Molur

The first ever attempt to remove the invasive (non-native) African Catfish Clarias gariepinnus from a canal of the Periyar Lake and Stream System (PLSS) in the Periyar Tiger Reserve, Kerala held on the 30th April 2013. A trial/ pilot attempt was tried out to reduce the threat from invasive fishes faced by the threatened and endemic native freshwater fish found in PLSS.

Volunteer with his catch of the African Catfish

The African Catfish is an exotic freshwater fish not native or naturally found in India. It is a hardy fish and can tolerate adverse water conditions and feeds on live prey and dead meat. It has been introduced into the freshwater systems in India over the last few decades and has established itself at the cost of many native fishes. It is a threat to the native endemic freshwater fish in Periyar as it occupies a certain niche, is a competitor for the same resources and can reproduce prolifically. This threatens the endemic freshwater fish in Periyar and hence needs to be eradicated.

The one-day attempt was made with the help of volunteers, the forest guards, fish experts and conservationists as a collective effort. The fish was baited with chicken intestine using hook and line method and indigenously developed wire-mesh cages. The volunteers were divided into five teams with a team leader, forest guard and forest officer accompanied each team. The team also consisted one member from the organisers and one volunteer who was to act as a rescue person in case a native fish was caught. The teams were provided with two plastic bags (one for the catfish and one with water for native fishes, if any). All exotics caught were collected in one place, measured, weighed and given to the Eco-Development Committee for safe disposal.

The entire event was organized by the Conservation Research Group in collaboration with the Zoo Outreach Organization, Indian Alliance for Zero Extinction, Periyar Foundation, Periyar Forest Department, Periyar Eco Development Committee, Invasive Species Specialist Group, Freshwater Fish Specialist Group, Friends of Target 12, the Ruffords Small Grants Foundation, Critical Ecosystem Partnership Fund, Ashoka Trust for Research in Ecology and the Environment and a host of eager and helpful volunteers without whom the exercise would not have been possible.

Briefing of volunteers on Do's and Dont's in Periyar Tiger Reserve

Length and weight data of the African Catfish that were caught

Result: About 100 individuals of the African Catfish were caught and removed from the canal. These individuals were measured and weighed for data analysis. Not a single native fish was caught in this exercise. This programme helped create awareness about the problem of invasive species and the impact that they can have on our native fish. The forest department was very supportive and is enthusiastic to have more such exercises. Also, any plastic waste that was found in the vicinity of the canal was removed.

PTR invasive catfish removal poster

Behind the scenes:
1). The activity was planned pre-monsoon since the canal is connected to the lake during peak monsoon and catfish from the canal can travel into the lake, which can spell disaster for the native fish. 2). The canal was chosen as a location after looking at the habitat preferences of the African Catfish, the canal would provide an ideal set up for a first-of-its-kind exercise in the country, since it is not a very large area it would mean easier coordination between the volunteers and the experts. 3). A poster to distinguish native fish (that could have occurred in the canal) from the African Catfish was provided to all volunteers. The volunteers were informed of the rules to be followed within Periyar Tiger Reserve.