Final Report
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Ela Foundation & Mangrove Cell. GOI/UNDP Project Final Report SURVEY OF OTTER SPECIES AND BENGAL MONITOR Varanus bengalensis IN MANGROVE HABITATS OF SINDHUDURGA DISTRICT, MAHARASHTRA Principal Investigator: Chief Conservator of Forests Mangroves, Mumbai Co-Investigator: Ela Foundation, Pune. Principle Researcher from Ela Foundation: Dr. Satish Pande, MB, MD, DNB, PhD (Ornithology); F.M.A.Sci., FLS With Anant Gokhale, Ram Mone, Rajkumar Pawar, Shivkumar Pednekar, Rahul Lonkar, Prashant Deshpande, Dr. Satish Karmalkar and Sudhanwa Rajurkar November 2015 to June 2016 (Photograph by: Dr Satish Pande, Ela Foundation, Pune) 1 Ela Foundation & Mangrove Cell. GOI/UNDP Project Contents Background … 3 Study Area … 4 Objectives … 4 Methodology for Otter and Monitor Lizard Survey … 5 Observations … 7 Analysis … 10 Conclusions … 13 Recommendations … 14 Appendix I: Photographs taken in the field Appendix II: Survey Data Tables and Maps Appendix III: Trap Camera Photographs Appendix IV: Survey Team 2 Ela Foundation & Mangrove Cell. GOI/UNDP Project Background There are possibly six species of otter occurring in Asia – 1. Eurasian Otter (Lutra lutra), 2. Smooth-coated Otter (Lutrogale perspicillata), 3. Asian Small-clawed Otter (Aonyx cinerea), 4. Hairy-nosed Otter (Lutra sumatrana), 5. Japanese Otter (Lutra nippon) and 6. Sea Otter (Enhydra lutris). Out of these, the first three species are reported from India. (http://www.otterspecialistgroup.org). Otters [Mustelidae Family] are poorly studied aquatic mammals. No comprehensive data for the populations and current status of this taxon is available for the Sindhudurga district, Maharashtra, India. The sporadic sightings are rare, mostly in and around mangroves and the habitats are not easily accessible. In this scenario, focused studies such as the one in the present proposal shall provide the much needed scientific data for the conservation of this species. The distribution of Bengal Monitor Family: Varanidae Varanus bengalensis is poorly documented in coastal areas. Hence, this species was also surveyed. The preliminary findings from the survey are presented in this report. 3 Ela Foundation & Mangrove Cell. GOI/UNDP Project Study Area (Transects): The survey for otters and monitor lizards were conducted in Mangrove patches in the coastal areas in Sindhudurga district, Maharashtra. The creeks and backwaters in Sindhudurga where the surveys were conducted included: 1. Vijaydurga Creek – Shanti River 2. Vadatar Creek –Piyali River 3. Devgad Creek and backwaters 4. Mithbav Creek – Naringre River 5. Achra Creek – Achra River 6. Kalaval - Tondavali Creek – Gad River 7. Kolamb Creek and backwaters 8. Karli Creek – Pithdhaval River 9. Mochemadi Creek – Talavade River 10. Aravali Creek and backwaters 11. Aronda Creek and backwaters 12. Terekhol Creek – Otawane River Objectives: 1. Document the diversity of otter species in the study area. 2. Record the distribution of otters and map the GPS coordinates. 3. Document the sites where otters are present. 4. Characterize habitat preference of otters. 5. Study the food preferences by field observations or prey remains. 6. Record the distribution of Monitor Lizard and map the GPS coordinates. 7. Identify threats to otter and Monitor Lizard. Number of visits and data analysis: Total 30 visits were carried out during the period from November 2015 to Jun 2016 for the study of otters and monitor lizards in the Sindhudurga district. Data was analyzed during February 2016 and November 2016. 4 Ela Foundation & Mangrove Cell. GOI/UNDP Project Methodology for Otter and Monitor Lizard Survey CONSISTENCY OF SAMPLING: 1. Same methods were used for transects. 2. GPS methodology was used to record otter presence sites. 3. Same researchers conducted the survey in all creeks. SPECIES IDENTIFICATION: Species identification was done from photographs and / or pugmarks and comparing them with diagnostic keys from published data. SURVEY TECHNIQUES: Study was done strictly as per the provisions of the WPA 1972. Field observations were taken as follows: For the crepuscular species like otters (small to medium sized aquatic mammals) a combination of techniques were used as follows: (GPS locations of otter sightings were recorded). 1. Visual Creek/River Boat Transects by non-intersecting line transects from boats by sailing along the tidal creeks, backwaters and rivers for each of the 12 creeks. 2. Bank Line Transects –(ISU) for 600 m at 6 sites in each 10 km stretch. These sites are designated as the Intensive Search Units (ISU). GPS locations of otter sightings were recorded for all positive sites. Transects shall were made for each of the 12 creeks. 3. Under Bridge Surveys (because spraints/scats tend to stay longer in these areas as compared to on open banks). GPS locations of otter sightings were recorded. 4. Modified Scent Station Surveys: The prawn and crab farms in the study areas were used as modified scent stations. Such sites were visited to find the presence or absence of otters. GPS locations of otter sightings were recorded. 5. Trap Camera Surveys were be conducted at pre-selected sites for following parameters: Confirmation of presence of otters, Identification of otter species, Group compositions, Behavior and 5 Ela Foundation & Mangrove Cell. GOI/UNDP Project Presence of other animals particularly monitors lizards. 6. Supplementary data from questionnaire response from local fishermen. See Appendix I observations recorded during the creek-wise surveys. UNITS OF THE DATA: 1. Otter Presence / Absence for study sites. 2. Identification of otter species. 3. Group composition and population. 4. Presence of monitor lizards and populations. Smooth-coated Otter family in the mangrove habitat in Sindhudurga district, Maharashtra (Photograph by: Dr Satish Pande, Ela Foundation, Pune) 6 Ela Foundation & Mangrove Cell. GOI/UNDP Project OBSERVATIONS 1. DIVERSITY OF OTTERS IN THE STUDY AREA a. Species: Our survey revealed that only one species of otter; the Smooth-coated Otter Lutrogale perspicillata was present in the mangrove habitats in all the creeks of Sindhudurga district. The photographs taken during the survey are presented in Appendix I. Otters are generally well known among the fishing community and are called as Hud, Ood and Uda in Marathi language. 2. OTTER DISTRIBUTION AND GPS MAPPING: Presence of otter sparints and otter sightings were important indicators of otter presence for recording their distribution. GPS coordinates of all survey sites including intensive survey units (ISU’s) were recorded. Smooth-coated Otter Lutrogale perspicillata was present in all the 12 creeks. Table 13 in Appendix II summarizes creek-wise otter presence / absence data. 3. OTTER PRESENCE SITES a. Creeks: The sites of otter presence are detailed as GPS coordinates of each ISU (Table 1 to 12 in Appendix II). The GPS Maps are also shown in Maps 1 to 12 in Appendix II. Otter spraints are the most reliable indicators for the presence of otters. Otter spraints are visible on open banks along the creeks, on Kharland Scheme bunds and also on the coasts. However, they are not seen when the coasts are occupied by dense mangroves. b. Minor Irrigation Tanks (MI Tanks): The presence and absence data of Smooth- coated Otter is shown in Table 14. In all 14 MI Tanks were surveyed, of which only 3 MI Tanks showed presence of otter as evident by spraints out of which in 2 MI Tanks otters were also sighted. The remaining 11 MI Tanks were negative for otter presence. Detailed scrutiny of the MI Tanks showed that otters were present only in those MI Tanks that were connected with the creeks. The MI Tanks positive for otter presence were Tithawali (5 otters), Hatheri (4 otters) and Harkul (spraint data). (Table 14 and Map 14.) c. Under Bridge Surveys: In all 17 bridges in all the creeks in Sindhudurga district were surveyed for otter presence. 16 bridges showed presence of otters as evident by spraints. We therefore conclude that otter spraints are reliably seen under bridges where they remain for a long time and old spraints could also be seen and recognized by their brittleness and white colour. (Table 15). 7 Ela Foundation & Mangrove Cell. GOI/UNDP Project d. Otter sightings are relatively rare as compared to otter spraints. During the study a minimum of 2 otters and maximum of five otter individuals were sighted at one time. As per the supplementary local information the otter groups between 9 to 12 individuals were regularly observed. Otters mostly exhibit crepuscular habits but also were recorded fishing and swimming during the noon in our study. Otters were associated with mangrove habitats along the creeks and they use mangroves for cover and resting. e. Modified Scent Station Surveys: 6 modified scent stations were surveyed. These were crab and prawn farms. Large sized spraints of otters (up to 3 m x 3 m) were seen in all 6 stations. Otters were sighted in one station (n =4; Meethbav-Naringre creek). Hence we conclude that Modified Scent Stations are reliable sites for presence of otters due to abundance of food in a small area. (Table 16). f. Trap Camera Images: We could get otter pictures in trap cameras installed in various sites that were previously documented positive for otter presence. (Trap Camera Photographs in Appendix III). 4. HABITAT PREFERENCE: A] Otters were recorded in: i. all creeks and backwaters with mangrove habitats, ii. on the coasts near fishing jetties at the time of fish harvesting (rapan), iii. on Kharland bunds, iv. narrow roads with creek on one side and seepage water on the other side v. sandbars in offshore areas, vi. MI Tanks with sweet water that were connected to the creeks or rivers, vii. near crab and prawn farms. B] Otters were not recorded where: 1. human disturbance was significant, ii. coastal areas with infrastructure development, ii. sand dredging activity was ongoing, iv. where thick mangrove cover made accessibility to the water body impossible making this a false negative site, v. such sites where otters were killed in the past.