Flushing pet fish or turtle down the toilet or releasing them in a pond, letting a pet bird fly away, abandoning a pet dog or cat does not only endanger their life but it can also set off a possible biological invasion in the future.
The much loved pet could become an invasive species and destroy an entire eco-system, said scientists at CSIR-Centre for Cellular and Molecular Biology (CCMB).
Stray cats and dogs are considered among the worst invasive species in the world and are responsible for killing scores of native birds and terrestrial animals annually. Invasive species are also responsible for incurring huge economic losses every year for the country, said invasion biologist Gopi Krishnan from Dr. G. Umapathy’s lab in an official online post.
Biological invasion is a multi-step process wherein a species is intentionally or accidentally transported for agriculture, ornamental or recreation purposes and then introduced to a new location outside its natural range. This species may soon establish a self-sustaining population and disperse to other regions. Since it negatively impacts the new ecosystem it is called an invasive species, although they are not inherently invasive.
Mr. Gopi Krishnan took the example of the aquarium cleaning, catfish like ‘armoured sailfin’, which is just about two inches in size but can grow up to two feet in length when let out into a pond. Catfish species from South America are very popular among aquaculture hobbyists in the country as they do not need high maintenance and also help keep the tank clean by feeding on algal growth.
When the pet owner wants to give up the fish, usually it is released into a nearby pond or a lake where they grow into huge numbers and lead to decline of native fishes through competition for food and other resources. Their sharp bony plates provide them protection against potential predators such as birds and other fishes. They can also damage fishermen nets when caught, though these fish are not a delicacy, he said.
Other fish species like goldfish, alligator gar and arapaima, too, can grow into huge sizes, up to five feet in length. Rose-ringed parakeet, Burmese pythons, red-eared slider turtles are other examples of ‘pets’ becoming invasive species after initially moved as part of the pet trade, Mr. Gopi Krishnan explained.
He pointed out that Australia has been trying to control rabbit population there owing to the havoc they have been wreaking on crops, land and native biodiversity. This population originated from the 24 rabbits introduced for gaming in 1859.
Controlling invasive species is extremely difficult due to the lack of natural predators, high reproduction, adaptability to newer conditions, etc. Government departments and voluntary organisations have been been working towards tackling invasive species by conducting eradication drives, monitoring illegal pet trades, etc., said the scientist, who called for “collective action”.
He urges citizens to register their pets – dogs, cats or any other animal — with the authorities, take licence/permission and learn about the species by consulting a biologist or doing a simple Google search. Most important, those wanting to give away their pet should contact animal shelters or animal welfare organisations instead of letting them loose into the open. Buying exotic and banned pet species should be avoided, added Mr. Gopi Krishnan.