Changing temperature and precipitation regimes are responsible for shifting the balance of nature. The sudden change in climate alters the habit and habitats of floral and faunal diversity including the aquatic species. Technically, climate change expanding the growth of invasive species and undergoing significant changes in their ecological character are some factors for vanishing of any kind of species (land & water) .
Similarly, eutrophication disturbs the water quality of rivers leading to reduction in the overall water holding capacity and its aesthetic value. The fish species ‘Ngawa’ (Baril) is one of the delicacies for the people of Manipur; known for its sweet taste is disappearing from the river, Khuga. Studies suggest that the reason behind the loss of Ngawa is due to delicate ecological balance, unchecked large-scale deforestation and natural factors like climate change.
Out of the six Barilius species distributed in the state, the three species Barilius basna, Barilius bendelisis and Barilius doger singhi inhibit in the Khuga River. Though still found rarely in the hilly stretch of Khuga River, the fish has almost gone extinct from the River’s valley stretch.
Since it is adapted to fast flowing, cold and oxygen rich water, the disappearance of the fish could also serve as an alarm for the harmful effects that climate change can Cause. Quoting data maintained by the Directorate of Environment and Climate Change, Senior Consultant (Scientific) Dr Manichandra Sanoujam pointed out that the Khuga River originates from the north of Churachandpur district neighbouring Myanmar near border pillar 46 having a total of 600.1 square kilometres catchment area. After passing the hilly stretch of 66.6 Km, the river starts its journey in the valley near Mata village in Churachandpur district which then travels for another 47.2 Km before merging with the Manipur River at Ithai village in Bishnupur district.
He expressed that reduction in the rate of flow of the river, rise in temperature and scanty rainfall are possible reasons for disappearing of Ngawa species. The Baril is a surface feeder which consumes its food by filtering water through its gills. The species would not survive when the water becomes muddy or less oxygenated.
The extensive extraction of minor minerals such as stone pebbles and sand which serve as a natural aerator thereby oxygenating the river, could also be one of the reasons for the disappearance of the fish species, according to the senior consultant. He also said that other species like Ngara (Tor putitora), Thangonpanbi (Schistura vinciguerrae), Ngaton (Bangana dero), Sareng Khoibi (Botia berdmorei), Nganap (Glyptothorax species), Ngasep (Mystus cavasius), Ngaril Laina (Anguilla bengalensis Gray), etc., need survey before they meet the same rate of ngawa.
On the other hand, the disappearance of Ngawa has not only impacted the ecosystem but also the lives of local fishermen who rely on the river for their survival. Many fishermen have now shifted their occupation as not only Ngawa but many other fish species have reduced drastically to the extent that they hardly managed to get a good catch.
According to Moirangthem Dhananjoy, a fisherman in his 70s of Phougakchao Ikhai in Bishnupur district, the rate of flow of water in the river has changed drastically in the past few years. A couple of decades ago, especially during monsoon, the river would even over flow and cause havoc in the surrounding farmlands, Dhananjoy recalled, adding that, at present, as there is less and less rainfall, the water level isn’t half the volume as it used to be.
On the other-hand, ICAR Research Complex for North Easter Region Manipur principal scientist (Fishery) Dr Ch Basuda pointed out that climate change, habitat loss and degradation in water quality are major causes for the disappearance of Ngawa from Khuga River. Dr Basuda said that depending on the species the Baril (Ngawa) sizes range from just two inches to a foot in length and they prefer fast flowing, cold and highly oxygenated water. The disappearance of the fish is a clear indication that the temperature of water has become warmer and less oxygenated, she cautioned, adding that, with a specific fish disappeared from a particular habitat could also mean extinction of several other fishes.
Equilibrium between breeding and fishing should be maintained to conserve it from complete extinction, she said. Dr Basuda opined that identification of vulnerable fish species and declaration of sanctuary for its habitat, afforestation programmes along with awareness especially in the catchment areas, ban on unethical way of fishing, prohibition of fishing in breeding season and more researches will not only help conserve the species which are on the brink of extinction but will also help mitigate climate change.
Awareness among the villagers is the only solution to protect the fish species from Khuga River. Locals must strictly follow the rules and regulation for conserving the floral and faunal diversity presence inside the river. Promoting education regarding conservation issues will be helpful.
Besides, information on aquatic status, population and community interactions and their contributions to ecosystem development is needed for effective conservation of aquatic management in the surrounding areas. Most importantly, monitoring of rivers from time to time is absolutely necessary. The climate change will force each and every individual species to adjust in this era. It is the right time to check fishes behavioural which can be used as a role model to track the mechanism and velocity of climate change in the state.