Although India is rich with the availability of freshwater fishes, currently suffering due to may problems such as water pollution, deforestation, habitat loss etc. But in few areas there is one more threat to native fish biodiversity, the invasion of non-native species such as ‘tilapia’.
After independence, the Indian government encouraged people to focus on increasing the food production from agriculture and other food sources to become independent in this area. That period ‘tilapia’ is introduced to India to increase the fishery production. Basically this fish is from Africa particularly from southwestern parts of Africa. This exotic fish very soon escaped from the cultured sites and invaded in the natural ecosystem. Its omnivorous nature, capacity to sustain in the polluted water, high reproduction rate, and good parental caring nature made it successful invader into the Indian freshwater ecosystem at many places.
In commercial terms, tilapia farming can be very successful and million dollar business, provide food to many people, with job opportunity and money source to rural area people. But which role tilapia plays in the native ecosystem if escaped from the commercial farms?
After the collapse of the Soviet Union, India focused on the industrialization to come with the new identity as ‘a developed nation’ instead of ‘a developing country’. Many traditional businesses converted into small and small to medium scale factories after that. This resulted into increase in the pollution and depletion of natural resources. Rivers get polluted and finally the native fishes in the rivers are started to be disappeared. But such condition was favorable for tilapia because it can sustain in the polluted water too. It can keep itself alive and reproductive in muddy or clean, alkaline or acidic, fresh or brackish, moving or stagnant water with less or more dissolved oxygen value.
The reproduction rate and growth rate is high in tilapia. Female lays unfertile eggs and male fertilize that with their sperms as many other fish species but difference is that, tilapia is very much sensitive to take care of their eggs and babies. Male also take care of his offspring aggressively. This results in less death rate and increase in tilapia in that habitat. In general, native fishes generally live although in same habitat but with different niche. For example, rohu, catla and mrigal are the fishes show different niche such as different layers into water in same habitat. But tilapia needs many niches during the reproduction stages.
Tilapia defend eggs and newly hatched babies. As it is omnivorous it can eat both plants and animal food such as from algae, plankton, invertebrates, eggs and fingerlings of other fishes etc. This can impact on the availability of food to other fishes. The baby tilapia grow quickly and reach to maturity to produce next generation. This make its availability easy in the water and other fishes and became rare. With these adverse environmental health, it can become responsible for the adverse impacts on human health too.
Due to easily availability (difficult to get other fishes), lots of flesh or meat with pleasant taste, tilapia is famous in many Indian dishes and curries. If you don’t know which fish you are eating, then there are more chances that you are eating tilapia. Due to its potential to live in the polluted water, consume everything it can show many toxins and heavy metals in its body.
Now you can answer better, would you like fish curry?