SCIENTIFIC CORRESPONDENCE CURRENT SCIENCE, VOL. 121, NO. 2, 25 JULY 2021 195 same. The polished sections for selective samples of the flaky carbon lenses were analysed using Raman spectroscopy at National Centre of Excellence in Geosci- ence Researches, GSI Kolkata. Three point measurements each for two poli- shed sections gave graphite band (G) (Figures 3 and 4; 1580 and 1581 cm –1 re- spectively) 6 establishing the prevalence of graphite (Figure 2 d). The graphite lenses extend for a cumulative 650 m length and 20 m average width. The fixed carbon values of systematic chan- nel/groove sampling of graphite lenses ranged from 2.06% to 5.85% (Table 1), against the Indian Bureau of Mines cut- off of 2% for crystalline flake variety. The documentation of graphite lenses within the Palaeoproterozoic Mahakoshal Group increases the possibility of un- earthing of rare earth elements and vana- dium usually associated with graphite. In addition, the presence of huge malachite stains (Figure 2 b and c) and at places malachite and azurite encrustations sup- ported by encouraging copper values up to 1.4% in the CP, suggest the multi- mineral potential of the area. Although earlier explorations carried out in this ar- ea for base metals did not result in delineating any significant resource 7,8 , the confirmation of graphite in this do- main opens up new opportunities for re- evaluating graphite potential of the area. 1. Roy, A. and Bandyopadhyay, B. K., Geol. Surv. India, Spec. Publ., 1990, 28, 226– 240. 2. Roy, A., Hanuma Prasad, M. and Devara- jan, M. K., Gondwana Res., 2002, 5, 489– 500. 3. Acharyya, S. K., Gondwana Res., 2003, 6, 197–214. 4. Kanchan, V. K. and Pandhare, S. A., Re- port, Geological Survey of India, 1974, Accession no. 11043. 5. Tripathi, U., Yuvraj, M., Ravishankar, D. and Gupta, M. K., Report, Geological Sur- vey of India, 2013, Item no. 007/ STM/CR/MP/2012/005. 6. Tuinstra, F. and Koenig, J. L., J. Chem. Phys., 1970, 53, 1126–1130. 7. Dutta, S. M. and Mathur, A. L., Report, Geological Survey of India, 1978, Acces- sion no. CR-014437. 8. Mathur, A. L., Report, Geological survey of India, 1979, Acc. no. CR-015520. ACKNOWLEDGEMENTS. We thank the ADG and HOD, Geological Survey of India (GSI), Central Region, Nagpur for providing the necessary facilities for this study; Hemraj Suryavanshi (NMH-II) for technical guidance and also for foreseeing the potential of the study area. Tapan Pal (Deputy Director Gen- eral, GSI, Madhya Pradesh) for discussions during the preparation of this manuscript; Sandip Nandy (Director, SU: MP, Jabalpur) for technical guidance regarding Raman spec- troscopy analysis; Gladson Bage and D. Ravisankar, Senior Geologists, for formulat- ing this project, and Rupsa Mukherjee (NCEGR, GSI, Kolkata) for timely analysis of the samples for Raman spectroscopy. We also thank the subject editor Prof. N. V. Chalapathi Rao (Banaras Hindu University, Varanasi) for useful suggestions. Received 22 April 2021; revised accepted 20 June 2021 PATEL VANIT VIJAYBHAI * PRABHAT KUMAR SAHU A. K. TALWAR Geological Survey of India, Central Region, State Unit Madhya Pradesh, Jabalpur 482 003, India *For correspondence. e-mail: vanitpatelfr@gmail.com Light-weight unmanned aerial vehicle surveys detect dugongs and other globally threatened marine species from the Andaman and Nicobar Islands, India Unmanned aerial surveys are used across the globe to study marine megafauna as they cover large spatial scales, reduce survey effort and time, and are cost- effective 1,2 . Due to their utility in cover- ing large areas and accessing remote locations, aerial surveys act as excellent tools to monitor several marine taxa such as elasmobranchs 3,4 , marine turtles 5 , pin- nipeds 6 , cetaceans 7 , and sirenians includ- ing manatees 8 and dugongs 9,10 . Dugong is a globally threatened spe- cies of order Sirenia, assessed as vulner- able according to IUCN Red List of threatened species 11 . Its distribution spans from the east coast of Africa, parts of the Red Sea to the Indo-Pacific region, including India, Sri Lanka, Indonesia, Thailand, Malaysia and Australia 12 . In India, dugongs are found along the coasts of Gulf of Kutch (Gujarat), Gulf of Man- nar and Palk Bay (Tamil Nadu), and Andaman and Nicobar Islands 13,14 . Also, their population in the country is consid- ered regionally endangered 11 and is estimated to be less than 200–300 indi- viduals 14 . This has prompted the Govern- ment of India to initiate the Endangered Species Recovery Programme for their long-term conservation and persistence 15 . However, estimating dugong population through traditional methods such as boat surveys is difficult in India due to their low detectability on the sea surface (lack of a prominent dorsal fin like dolphins) and rare occurrence (low population size) 14 . Aerial surveys have been previ- ously utilized to study dugong distribu- tion, estimate populations and determine their habitat use patterns in Austra- lia 10,16,17 . In India, though aerial surveys were recommended to study dugongs 12,18 , no efforts were undertaken prior to this study. In the present study, we conducted reconnaissance aerial surveys to detect dugongs with an aim to systematically estimate their populations from known habitats. These areas have been identi- fied with the help of dugong volunteer- ing network established at the Andaman and Nicobar Islands consisting of fisher- folk, divers, boat operators and other regular seafarers 15 . The surveys were carried out with the involvement of the Department of Environment and Forests, Andaman and Nicobar Islands within the Marine Protected Areas of Mahatma Gandhi Marine National Park and Rani Jhansi Marine National Park, and