Biodiversity of fishes in Manipur - Prof. W. Vishwanath
The diversity of species in the North Eastern India region is attributed to the recent geological history, especially the Himalayan orogeny. Since both the Brahmaputra and Chindwin system of rivers drain Manipur, its fauna included both Asamese and Burmese elements. Though, there is great specific diversity, the genera of the Brahmaputra and the Chindwin drainages are almost the same. Fresh water from the Indian mainland would have migrated towards Myanmar and other parts of south east Asia only then. Thus, the species of fishes in this region probably evolved only very recently from their old gondwanan ancestor. The diversity is attributed to the vigorous movements of earth’s crust and constant changes in the courses of waters.
THREATS TO MANIPUR FISHES
The freshwater fishes of the Eastern Himalaya were assessed and evaluated to assign their threat criteria and red listing by the International Union for Conservation of Nature (IUCN) in 2009-10. Out of more than 580 species assessed, 50 were found Vulnerable and 15 were reported as Endangered. Twenty-seven species in Manipur are Vulnerable and 10 (ten) species were Endangered. Of the whole eastern Himalaya, the most threatened fishes are confined in Manipur and its adjoining areas.
Map Showing Threatened Freshwater Fish Species Richness - IUCN
What is to be done to save the fishes?
There are means to save the threatened fishes and their habitats. Some of them are as follows:
-Availability of water and maintenance of water quality is the foremost requirement for fishes to survive. Afforestation is a means to retain water and reducing soil erosion in catchments. An extensive social forestry programme and controlling of shifting cultivation would bring a change and reduce silt burdens in rivers.
-There is need for water quality monitoring, assessment and control and also use of pollution reduction technologies.
-Dam and river management authorities should try to restore natural flow regimes and restore the migratory routes of fishes. EIA (Environmental Impact Assessment) has important roles to play in this matter.
-Concerned authorities should assess any species before introduction whether it would affect the native species and the habitats. Control of unwanted introduced species is urgently needed to prevent further impact.
-Destructive fishing techniques such as dynamiting, poisoning and electric fishing should be prevented. Catching of brooders and juveniles be banned.
-Research and training on taxonomy and habitat ecology and biology of fishes is essential for the conservation and sustainable use of threatened fishes.
-Fish sanctuaries for the protection of threatened species or vulnerable habitats should be established in suitable areas.
-Participation of local communities in the conservation of fishes and their habitats is required. Thus there should be education to make the people understand the problems.
The largest global environmental network, International Union for Conservation of Nature(IUCN) has listed 15 fish species including 7 from Manipur as ‘endangered freshwater fish species’ in their recently released Red list of threatened species report on the status and distribution of freshwater biodiversity in eastern Himalaya which covers the entire NE states and parts of eastern India, Bangladesh, Nepal.
Manipur’s 7 fishes in the IUCN red list are Ngakha Meingangbi(Puntius manipurensis)Ngatup (Schistura Kanjupkhulensis ), Ngatup makhal ama (Schistura minutes), Ngatup manba nga (Schistura reticula), Ching-ngakra (Pterocryptis barakensis), Ching-Ukabi (Badis tuivaiei) and Nung-nga (Psilorhynchus microphthalamus).
A 6 member research team headed by renowned fish researcher Prof Waikhom Vishwanath of Manipur University’s Life Science department conducted the research work on the status and distribution of freshwater fishes of the eastern Himalaya region which comprises Ganga delta and plain, Ganga Himalayan foothills, Upper Brahmaputra, Middle Brahmaputra, Chin hills-Arakan coast and Sittang-Irrawaddy eco-region, for compiling IUCN’s Red list report.
The other co-researchers are Heok Hee Ng of National University of Singapore, Ralf Britz of The Natural History of Museum,London,L Kosygin Singh of Zoological Survey of India(Orissa),Shivaji Chaudhry of BG Pant Institute of Himalayan Environment and Development and Kevin W Conway of Texas and A&M University.
“It took one year to compile it(IUCN’s report) by studying 115 fish species out of 520 species found in the eastern Himalaya region”,Prof W Vishwanath said.“Interestingly out of the 50 freshwater fishes listed as vulnerable there are 23 more fish species from Manipur”.
According to the IUCN document, half of fish species (263) in eastern Himalaya are categorized as Least Concerned while 27 per cent (141 species) are under Data Deficient category.
Only 1 per cent of the species (5) are Critically Endangered including one nemacheiline loach, Schistura papulifera is endemic in eastern Meghalaya’s Krem Synrang Pamiang cave system in Jaintia hills, while Endangered occupies hardly 3 per cent species(15). Besides 9 per cent of them(46) categorized as Near Threatened category.
Though no species was categorized as globally extinct or extinct in the wild in the eastern Himalaya assessment region, Manipur`s state fish Pengba (Osteobrama belangeri) was reported to be regionally extinct in wild as the route of this Ayeyarwaddy basin(Myanmar) origin minor carp has been disturbed with the construction of Ithai barrage across Manipur river for the operation of Loktak hydro-electric project 28 years ago.
Drying up of wetlands due to siltation and conversion of Loktak,largest freshwater lake in NE India(40,000 hectare),into a water reservoir after commissioning of the above project,causes drastic change in Manipur’s aquatic environment forcing many species including Nganap (Pangio pangia),Sareng Khoibi (botia berdmorei), Ngasep (mystus bleekeri) and Ngamu (Channa orientalis) vulnerable. Manipur has more than 200 fish species.
“Pollution,habitat lost,damming,over-exploitation besides species invasion are the major threats in Manipur,” Prof Vishwanath said when enquired. “Fishes in Chindwin basin in Manipur particularly Imphal river and its tributaries are so vulnerable unlike the Bramhaputra basin where the species may find similar habitat for their survival.”
Besides the development of Moreh(India) and Tamu(Myanmar)-both border townships for 16 year old Indo-Myanmar border trade has impacted on the aquatic environment in Lokchao river in Manipur and Yu river in Myanmar.
Barak basin in south western Manipur is also under threat, the IUCN report added.Manipur’s western hills are drained by the Barak and its tributaries before it enters Assam’s Cachar district and finally enter Bangladesh to join Surma-Meghna basin.
The proposed development of the Tipaimukh High Dam hydro-electric project along Manipur-Mizoram-Assam border there will be flow modification and flooding of the Barak basin in the western part of Manipur.
“Many species endemic to the Barak basin including Ching-Ukabi(Badis tuivaiei),Ching-Ngakra(Pterocryptis barakensis),Ngatup manbi(Schistura minutus) and Ching-nga(Schistura tigrinum) are assessed as endangered or as vulnerable”,it added.