Ichthyofaunal diversity and conservation status of the Tsurang and Milak Rivers of Mokokchung District, Nagaland
Article Main
Abstract
Nagaland, located in northeast India, is rich in biodiversity and boasts numerous rivers that support a diverse array of fish species. However, the fish populations in the Tsurang and Milak rivers of the Mokokchung district remain largely unexplored. This study aimed to document the fish diversity in these rivers and assess their conservation status. Seasonal sampling was conducted from 2020 to 2023 using various fishing gear, and species identification was performed using standard taxonomic keys. A total of 37 fish species were recorded, belonging to 4 orders, 13 families, and 25 genera. The Milak river demonstrated greater species richness, with 32 species compared to 22 species in the Tsurang river. The families Cyprinidae and Danionidae were the most dominant, each comprising 10 species. The conservation assessment revealed that one species, Tor putitora, is listed as endangered, four species as vulnerable, and four as near threatened, according to the IUCN Red List. Significant anthropogenic threats, such as habitat degradation, open coal mining, and overfishing, pose serious risks to these freshwater ecosystems. The findings highlight the urgent need for sustainable management and conservation strategies to protect the ichthyofaunal diversity of the Tsurang and Milak rivers.
Article Details
Article Details
Keywords
Conservation, Fishery resources, Freshwater ecosystems, Ichthyofaunal diversity
References
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Vishwanath, W., Lakra, W. S. & Sarkar, U. K. (2007). Fishes of North East India. NBFGR, Lucknow, Uttar Pradesh, India, 264 pp.
Arthington, A. H., Dulvy, N. K., Gladstone, W. & Winfield, I. J. (2016). Fish conservation in freshwater and marine realms: status, threats, and management. Aquatic Conservation: Marine and Freshwater Ecosystems, 26(5), 838–857. https://doi.org/10.1002/aqc.2712
Baro, P. & Narzary, J. (2024). Maiden study on fish diversity of the Diring River in Baksa District, Assam, India. Journal of Fisheries, 12(3), 123202. https://doi.org/10.17017/j.fish.725
Cao, L., Shao, W. H., Yi, W. J. & Zhang, E. (2024). A review of conservation status of freshwater fish diversity in China. Journal of Fish Biology, 104(2), 345–364. https://doi.org/10.1111/jfb.15606
Chong, V. C., Lee, P. K. Y. & Lau, C. M. (2010). Diversity, extinction risk, and conservation of Malaysian fishes. Journal of Fish Biology, 76(9), 2009–2066. https://doi.org/10.1111/j.1095-8649.2010.02685.x
Cooke, S. J., Fulton, E. A., Sauer, W. H., Lynch, A. J., Link, J. S., Koning, A. A. & Gillanders, B. M. (2023). Towards vibrant fish populations and sustainable fisheries that benefit all: learning from the last 30 years to inform the next 30 years. Reviews in Fish Biology and Fisheries, 33(2), 317–347. https://doi.org/10.1007/s11160-023-09765-8
Dudgeon, D. & Strayer, D. L. (2025). Bending the curve of global freshwater biodiversity loss: what are the prospects? Biological Reviews, 100(1), 205–226. https://doi.org/10.1111/brv.13137
Ezung, S., Shangningam, B. & Pankaj, P. P. (2021). A new fish species of genus Garra (Teleostei: Cyprinidae) from Nagaland, India. Journal of Threatened Taxa, 13(6), 18618–18623. https://doi.org/10.11609/jott.6029.13.6.18618-18623
Ezung, S., Kechu, M. & Pankaj, P. P. (2022). First record of Garra birostris Nebeshwar & Vishwanath, 2013 (Cypriniformes: Cyprinidae) from Doyang and Dikhu rivers of Brahmaputra drainage, Nagaland, India. Journal of Threatened Taxa, 14(7), 21453–21457.
Ezung, S., Kechu, M., Longkumer, S., Jamir, A. & Pankaj, P. P. (2020). A review on the ichthyofauna of Nagaland, North-East India. World News of Natural Sciences, 30(2), 109–121.
Ezung, S., Shangningam, B. & Pankaj, P. P. (2020). A new fish species of the genus Garra (Teleostei: Cyprinidae) from the Brahmaputra basin, Nagaland, India. Journal of Experimental Zoology India, 23(2), 1333–1339.
Goswami, P. & Singha, S. (2023). Fish diversity of the Beki River, Assam, India: Present status and conservation needs. Ecocycles, 9(2), 1–6. https://doi.org/10.19040/ecocycles.v9i2.23
IUCN (2025). The IUCN red list of threatened species. Version 2025-1. Retrieved from https://www.iucnredlist.org (accessed on 16.102.25)
Jayaram, K. C. (2010). Freshwater Fishes of Indian Region (2nd ed.). Narendra Publishing House, New Delhi, 616 pp.
Kechu, M. & Pankaj, P. P. (2023). Traditional fishing methods practiced by Ao and Sumi tribes in Dikhu River of Nagaland, India. Journal of Fisheries, 11(2), 112202. https://doi.org/10.17017/j.fish.458
Kechu, M. & Pankaj, P. P. (2025). Checklist on the ichthyofaunal resources and conservation status of Dikhu River, Nagaland, India. Journal of Threatened Taxa, 17(2), 26504–26514. https://doi.org/10.11609/jott.9181.17.2.26504-26514
Kechu, M., Ezung, S. & Pankaj, P. P. (2023). Bionomics, length-weight relationship and condition factor of Chocolate mahseer, Neolissochilus hexagonolepis from Dikhu River, Nagaland. Journal of Environmental Biology, 44, 706–712.
Kechu, M., Ezung, S., Longkumer, S., Jamir, A. & Pankaj, P. P. (2021). Progress and prospects for sustainable production and conservation of threatened coldwater fishes of northeast India with special reference to Nagaland state. Journal of Experimental Zoology India, 24(1), 27–33.
Mishra, R. K. (2023). Fresh water availability and its global challenge. British Journal of Multidisciplinary and Advanced Studies, 4(3), 1–78. https://doi.org/10.37745/bjmas.2022.0207
Pankaj, P. P. & Pongen, R. P. (2025). Fishes of Nagaland: Status and new additions (1st ed., pp. 1–209). Academic Publishers and Distributors, Lucknow. ISBN: 978-81-985978-5-4.
Reid, A. J., Carlson, A. K., Creed, I. F., Eliason, E. J., Gell, P. A., Johnson, P. T. & Cooke, S. J. (2019). Emerging threats and persistent conservation challenges for freshwater biodiversity. Biological Reviews, 94(3), 849–873. https://doi.org/10.1111/brv.12480
Sayer, C. A., Fernando, E. & Jimenez, R. R. (2025). One-quarter of freshwater fauna threatened with extinction. Nature, 1–8. https://doi.org/10.1038/s41586-024-08375-z
Shilpa, Pankaj, P. P., Thakur, K., Brar, B., Kumar, S., Upmanyu, S., Sharma, D., Mahajan, D. & Kumar, R. (2023). Ecological implications of dam and barrage construction in the Indian Himalayan region: A comprehensive assessment. International Journal of Oceanography and Aquaculture, 7(2): 000239. https://doi.org/10.23880/ijoac-16000239
Talwar, P. K. & Jhingran, A. G. (1991). Inland fishes of India and adjacent Countries, Vols. I and II. Oxford and IBH Co. Pvt. Ltd., New Delhi, 1158 pp.
Tsurunla, K., Limatemjen, L., Konyak, S. L. & Chüzho, V. (2024). Fish fauna and their IUCN conservation status of Chessore sub-division of Shamator, Nagaland, India. World News of Natural Sciences, 56, 58–66.
Vishwanath, W., Lakra, W. S. & Sarkar, U. K. (2007). Fishes of North East India. NBFGR, Lucknow, Uttar Pradesh, India, 264 pp.
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Ichthyofaunal diversity and conservation status of the Tsurang and Milak Rivers of Mokokchung District, Nagaland. (2025). Journal of Applied and Natural Science, 17(4), 1745-1752. https://doi.org/10.31018/jans.v17i4.7005
