Middle Andaman Island Research Articles

Range extension and re-recording of Redigobius bikolanus (Herre, 1927) from Great Nicobar, India

Redigobius is a genus of goby fish belonging to order Gobiiformes. Redigobius is currently represented by 15 species worldwide of which Redigobius bikolanus is a widespread species. This species was recorded previously from Middle Andaman Island in 2002. There was not a single evidence of the species after that time, from Indian region. Recently, during a faunal survey in great Nicobar Island resulted in collection of a R. bikolanus for the first time and proving evidence for range extension of the same from Nicobar group of Islands. The species was collected from one of the estuarine creeks of Great Nicobar island. Details of the morphological data, live colouration and wild habitat are provided for the new record.

A biogeographic assessment of phytoplankton richness and composition in the Andaman Archipelago and the potential links to anthropogenic and environmental impacts: A multivariate approach

We report here a year-round baseline assessment on phytoplankton diversity and abundance from the pristine coastal waters of the Andaman Islands (September 2011–October 2012). A total of 84 phytoplankton species belonging to 47 genera were recorded from the North to South Andaman Islands. The maximum number of phytoplankton diversity (84 species under 47 genera) was recorded during the northeast monsoon (NEM) at a highly urbanized coastal environment like South Andaman Islands, whereas the minimum diversity (53 species under 34 genera) was recorded during the inter-monsoon (IM) period at the less anthropogenic activity sites viz. North and Middle Andaman Islands. All over seasons, the community composition of phytoplankton was mostly dominated by diatoms (45%–87%) followed by dinoflagellates (11%–46%) and blue–green algae (1%–35%). Besides, the abundance of phytoplankton was recorded as a gradual decrease from South Andaman to North Andaman Islands. The Canonical Correspondence Analysis (CCA) revealed the impact of physicochemical variables on phytoplankton assemblages. Thus, the temperature, salinity, and nitrite were the major environmental variables that influenced phytoplankton assemblage and distribution in the coastal waters of the Andaman Islands. The Principal Component Analysis (PCA) showed a strong variability of phytoplankton diversity in the South Andaman Islands (PC1: 32.6–36.2% variance). In addition, the Metric-multidimensional Scaling analysis also showed the gradual species intensity in the South Andaman than the Middle and North Andaman Islands.

A new record of Opisthobranch, Tayuva lilacina (Gould, 1852) and notes on Euselenops luniceps (Cuvier, 1816) from the Andaman Sea, India

The present study reports occurrences of two sea slugs namely, moon headed side-gilled slug Euselenops luniceps (Cuvier, 1816) and spotted foot nudibranch Tayuva lilacina (Gould, 1852) from the Andaman Sea. Euselenops luniceps (Cuvier, 1816) is a very rare species previously recorded from the Andaman and Nicobar Islands without any precise geographical location details, and this study confirms the occurrence of E. luniceps (Cuvier, 1816) from the North & Middle Andaman Islands. The spotted foot nudibranch, T. lilacina (Gould, 1852) is first time recorded from the Andaman Sea. Previously, these two species were recorded from both the east and west coasts of mainland India. These species are illustrated, described, and their distribution details in the Islands are provided.

Occupancy and Population Abundance of Two Serpent-Eagles (Spilornis elgini and S. cheela) in the Andaman Islands, India

ABSTRACT We estimated occupancy and population abundance of the Andaman Serpent-Eagle (Spilornis elgini) and Crested Serpent-Eagle (Spilornis cheela) in the Andaman Islands, India. We divided the islands that were > 100 km2 into a grid of 84 cells, of which we used 34 cells (5 km × 5 km each) for surveys of two populations in the districts of (1) the North and Middle Andaman Islands, and (2) the South Andaman Islands, which includes Little Andaman Island. We performed single-season, single-species occupancy modeling independently for both regions and single-season, two-species occupancy modeling for co-occupancy in the surveyed landscapes. The estimated abundance for the Andaman Serpent-Eagle and the Crested Serpent-Eagle was 4–5 and 7–8 individuals per 25 km2, respectively. The Andaman Serpent-Eagle is commonly distributed in both regions and has a high detection probability (detection probability, P = 0.8). The Crested Serpent-Eagle is widely distributed in the South Andaman Islands with a low detection probability (P = 0.5). The single-season, two-species occupancy model showed that the endemic Andaman Serpent-Eagle occupied only 22% of the area and did not co-occur with the Crested Serpent-Eagle. It also indicates the possible avoidance or exclusion of the Crested Serpent-Eagle by the Andaman Serpent-Eagle. We encountered both serpent-eagles in all the identified habitat types. The Crested Serpent-Eagle's habitat use was not restricted to the coastal forests, as previously reported, and the Crested Serpent-Eagle is probably dominating the Andaman Serpent-Eagle in the co-occupied areas. We further conclude that the occupancy dynamics and competition for space between these two Spilornis species might significantly affect the distribution and population of the vulnerable and endemic Andaman Serpent-Eagle in the future.

Constraints on the configuration of Andaman-Nicobar Subduction zone from EM modeling

The electrical conductivity structures, using Long period Magneto Telluric data at three sites: NBG (Nabagram) & HAV (Havelock) in Andaman and CBY (Campbell Bay) in Nicobar region are investigated. After obtaining 1D responses, 2D forward models of electrical structure are constructed along profiles across North Andaman, Middle Andaman and Nicobar Islands. The initial configuration along each profile is constrained from models based on seismic reflection data. The responses obtained after iterative forward computations match the observed data at respective sites reasonably well. New structures within the forearc high are discerned: from north to south we delineate a moderately conductive body beneath North Andaman, which is associated with the presence of ophiolites around this location, in the Middle Andaman, a highly conductive body below the island is interpreted as presence of fluids along the active Diligent Fault, facilitated by the barrier of the Invisible Bank. A complex geometry of resistive material embedded in a highly conductive body inferred beneath at Great Nicobar at CBY is commensurate with the presence of a layered magmatic body, possibly linked to the volcanic seamount to the east, near the tear of the subducting plate.

The Andaman day gecko paradox: an ancient endemic without pronounced phylogeographic structure

The Andaman day gecko (Phelsuma andamanensis) is endemic to the Andaman Archipelago, located ~ 6000 km away from Madagascar where the genus Phelsuma likely evolved. We complemented existing phylogenetic data with additional markers to show that this species consistently branches off early in the evolution of the genus Phelsuma, and this early origin led us to hypothesize that island populations within the Andaman Archipelago could have further diversified. We sampled the Andaman day gecko from all major islands in the Andamans, developed new microsatellite markers and amplified mitochondrial markers to study population diversification. We detected high allelic diversity in microsatellites, but surprisingly poor geographical structuring. This study demonstrates that the Andaman day gecko has a panmictic population (K = 1), but with weak signals for two clusters that we name ‘North’ (North Andaman, Middle Andaman, Interview, Baratang, Neil, and Long Islands) and ‘South’ (Havelock, South Andaman, Little Andaman Islands). The mitochondrial COI gene uncovered wide haplotype sharing across islands with the presence of several private haplotypes (except for the Little Andaman Island, which only had an exclusive private haplotype) signalling ongoing admixture. This species differs from two other Andaman endemic geckos for which we provide comparative mitochondrial data, where haplotypes show a distinct phylogeographic structure. Testing population history scenarios for the Andaman day gecko using Approximate Bayesian Computation (ABC) supports two possible scenarios but fails to tease apart whether admixture or divergence produced the two weak clusters. Both scenarios agree that admixture and/or divergence prior to the onset of the last glacial maximum shaped the genetic diversity and structure detected in this study. ABC supports population expansion, possibly explained by anthropogenic food subsidies via plantations of cash crops, potentially coupled with human mediated dispersal resulting in the observed panmictic population. The Andaman day gecko may thus be a rare example of an island endemic reptile benefiting from habitat modification and increased movement in its native range.

Assessment of plastic debris in remote islands of the Andaman and Nicobar Archipelago, India

An attempt was made in during August 2018 to study the plastic debris present in beach sediments at the remote islands of the Andaman and Nicobar Archipelago, India. The maximum number of plastic debris was noticed in the North and Middle Andaman Island sector and the Nicobar Island sector. White, irregular shaped polyethylene and polypropylene debris were the predominant plastic varieties found in the study area. The plastic litters disposed in the marine environment could be carried away by currents, which then circulate around the island and finally reach the coastal areas of the Andaman and Nicobar Archipelago. The plastic litter was contributed from tourist, shipping activities and improper handling of solid wastes.

Evaluating sensitivity of hyperspectral indices for estimating mangrove chlorophyll in Middle Andaman Island, India.

Mangroves are the highly productive and extensive ecosystem in the tropical coasts. Chlorophyll is the key foliar determinant of mangrove productivity. Optical characteristics of mangrove markedly differ from land vegetation; hence, defining narrowband spectral indices most sensitive to mangrove chlorophyll is crucial, in view of their importance to the coastal environment and mounting biotic pressures. We assessed the sensitivity of a set of satellite hyperspectral remote sensing indices to mangrove canopy chlorophyll in Middle Andaman Island, India, and propose most robust spectral indices for mangrove chlorophyll estimation. We generated simple, modified simple, normalized difference vegetation, and non-linear indices from all possible two band combinations of EO-1 Hyperion bands in the 500-900nm spectral range. The strength of correlation between each pair of spectral indices to mangrove chlorophyll was analyzed in 2D correlograms and validated using k-fold cross-validation technique. Results show that 549 nm,559nm (green) and 702nm, 722nm, 742nm, and 763nm (red-edge) wavelengths are the most sensitive to mangrove chlorophyll. We report performance of traditional chlorophyll indices and new indices with higher predictive capability for mangrove chlorophyll prediction. Simple ratio (559nm/885nm) offered the strongest correlation with mangrove chlorophyll (R2-0.75, RMSE-0.60, p < 0.05). Study findings will help researchers in deciding suitable chlorophyll indices for mangrove productivity and stress assessment. The best calibrated index was used to prepare mangrove chlorophyll spatial variability map of the study area.

Estimation of prevalence and screening of communication disorders in North and Middle Andaman and Nicobar Islands

ObjectiveAndaman and Nicobar Islands is a union territory in the Indian sub-continent. Though housing a highly diverse and large population, there is very limited data regarding the prevalence of communication disorder in this region. This information would play a crucial role in creating awareness amongst the people of the islands regarding communication impairments, providing rehabilitation services, and improving policies and facilities for the affected individuals. MethodThe study was conducted in two phases. The first phase involved a door to door survey. The survey was carried out across towns in North and Middle Andaman by NSS student volunteers and staffs of All India Institute of Speech and Hearing, Mysuru. During this phase, individuals with communication disorders were identified and referred for a two-day camp. The second phase involved diagnosis and rehabilitation of these referred individuals in a campsite set in a well accessible point in the city of Mayabunder. Results3.38% of the surveyed population was referred for the camp. Hearing impairment was found to be more prevalent than language and speech disorders. It was also found that delayed birth cry, low-birth weight and pre-mature delivery were the major risk factors of communication disorders in the region. Amongst the referred individuals who attended the camp, 46.8% of ear-related issues and 53.2% of speech and language disorders was estimated. It was also observed that males were more affected by communication disorder than females. ConclusionThe high prevalence values indicate the need for immediate action in terms of facilities and infrastructure in these regions for enabling a better quality of life of individuals with communication disorders.

Future Mangrove Suitability Assessment of Andaman to strengthen sustainable development

Islands are threatened by various natural and anthropogenic factors including climate change, overpopulation, unsustainable use of natural resources and increasing trend in seismic events. Therefore, studies on island in specific aspect (ecological, social and economic) is very essential for sustainable resource management and future development. Mangroves are highly important natural resources of coastal regions in respect to coastal livelihood and natural defense. Although, around 46% of the mangrove forest area has vanished worldwide in the last few decades. In this present research, Future Mangrove Suitability Index (FMSI) using the Analytic Hierarchy Process (AHP) method has been performed for sustainable forest management under the United Nations Sustainable Development Goal no 15. It is a new framework applied on North and Middle Andaman Island to determine the future distribution of mangrove forest. Land-use and land-covers (LULC) are prepared in supervised classification (maximum likelihood algorithm) techniques with 3000 signatures. A total number of fourteen parameters has been used in multi-criteria decision making (MCDM) platform to generate future scenarios. Among them, Representative Concentration Pathways (RCPs) projected climatic data (RCP 6.0 scenario shows the best result comparing to 4.5 and 8.5) and projected population data has been used for the first time in the investigated area. The final results are validated using 556 field sample point. Seven major sensitive parameters have been selected from sensitivity analysis and three statistical correlation analysis has been performed using 300 field points to generate the actual correlation between the parameters. The final outcome shows that major unsuitable zones are located in Diglipur tehsil whereas; highest suitable zones are located in Rangat tehsil region which are the result of the continuous increase of sea surface height (1.5 mm observed during 1980–2009), seismic events with frequent storm surges, anthropogenic influences and impact of climate change. Thus a planned sustainable development practice is essential to control the biodiversity loss and future livelihood management. Moreover, this study will strengthen future planning projects and researches in mangrove ecosystem management of Andaman.

Mangrove Wetlands of Dhani Nalla, Betapur and Baratang Island Gateway, Middle Andaman and Nicobar Islands, India- An Overview

Mangrove Wetlands of Dhani Nalla, Betapur and Baratang Island Gateway, Middle Andaman and Nicobar Islands, India- An Overview

Spatiotemporal roosting movements of the cave-dwelling Andaman Edible-nest Swiftlet (Aerodramus fuciphagus inexpectatus)

We collected data from 10 caves (3 sites) in the North and Middle Andaman Islands to determine the spatiotemporal changes in the roosting pattern of the Andaman populations of Edible-nest Swiftlet (Aerodramus fuciphagus inexpectatus). This echolocating diurnal aerial forager showed temporal variation in its round-the-clock entry and exit patterns. With spatiotemporal variations (site-wise, cave-wise, hourly, and monthly), more than 98% of birds returned daily to the roosting caves between 1700 h and 2000 h. However, their daily departure time (between 0400 h and 0700 h) did not vary spatially (site-wise and cave-wise). The movements of birds at the cave openings were higher during the nestling period in April and May. The daily roosting period inside the caves (mean 525.20 min; SD 82.98) also showed spatiotemporal variation. Day length affected movement of the birds before and after sunset and sunrise. We conclude that roosting movement of the Andaman Edible-nest Swiftlet varied spatiotemporally in the Andaman Islands. This first detailed description of such variation in the roosting patterns of the species will stimulate further exploration of the various biological and environmental factors affecting movements of this cave-dwelling endemic.

Channa royi (Teleostei: Channidae): a new species of snakehead from Andaman Islands, India

A new species of snakehead fish Channa royi sp. nov., has been described based on 21 specimens collected from the South, Middle and North Andaman Islands, India. It is distinguished from all its congeners by a greenish-grey dorsum, pale brown to black pectoral fin with 2-3 inconspicuous semicircular bands, a series of 7-9 obliquely-arranged, saddle-like, dark olive to grey oblique streaks on green background on upper half of the body, 42-45 pored lateral-line scales, 12-13 branched caudal rays, 6-7 pre-dorsal scales, 43 vertebrae, two rows of teeth on the lower jaw, an outer row of numerous minute slender, pointed teeth and single inner row of large uniform sized teeth without any large canine like teeth on the anterior fourth of the lower jaw. Phylogenetically C. royi sp. nov. is closely related to C. harcourtbutleri, with a genetic distance (K2-P) of 2.4-2.8%, but morphologically differs in having greater inter-orbital width, fewer pelvic-fin rays (5 vs. 5-7, mode 6); fewer caudal-fin rays (ii- i, 10-12, i-ii vs. ii, 15, ii); more pre-dorsal scales (6-7 vs. 4) and fewer mid row lateral-line scales (9-13 vs. 15-16). Though Channa royi sp. nov. is a part of C. gachua species-group, it differs from the topotypic C. gachua from Bengal with higher pair-wise sequence distance of 19.5-20.9%.

Evaluation of the Use of Hyperspectral Vegetation Indices for Estimating Mangrove Leaf Area Index in Middle Andaman Island, India

ABSTRACTMangroves are highly productive ecosystems of the coastal environment in tropics and subtropics. The Leaf Area Index (LAI) is a key structural variable of the canopy, useful for estimating the primary productivity of vegetation including mangroves. We evaluated the sensitivity of narrowband spectral indices viz., Simple Ratio, Normalized Difference Vegetation Index, Soil-Adjusted Vegetation Index and Non-Linear Vegetation Index to mangrove LAI, and thereby propose the optimal bands and spectral indices for mangrove LAI estimation. The study was carried out using EO (Earth Observation)-1 Hyperion data in the Middle Andaman Island, situated in the Bay of Bengal, India. We constructed simple, normalized and non-linear band indices from all possible band pairs in the Hyperion image, and correlated them with mangrove LAI, and empirical relationships were validated through a k-fold cross-validation. The 2-D correlation plot analysis indicates that wavebands in Shortwave Infra-Red and Near Infra-Red regions, have a high potential for mangrove LAI estimation. The wavebands at 834 nm, 844 nm, 864 nm, 1034 nm, 1185 nm, 1276 nm, 1296 nm, 1629 nm and 1679 nm were the most sensitive to mangrove LAI. The non-linear vegetation indices performed better than linear indices in predicting LAI of mangrove. The identified indices are expected to improve quantification of spatial variability of mangrove LAI.

Petrology of Peridotites and Nd-Sr Isotopic Composition of Their Clinopyroxenes from the Middle Andaman Ophiolite, India

The Andaman Ophiolite, India, is located at the southeastern end of the Tethyan ophiolites. We examine petrology and mineralogy of two lherzolites and a completely serpentinized dunite associated with lherzolite from the middle Andaman Island. Major and trace element compositions of minerals in the lherzolites suggest their residual origin after low-degree of partial melting with less flux infiltration, and are similar to those of abyssal peridotites recovered from mid-ocean ridges. The dunite with spinels having low-Cr/(Cr + Al) ratio was formed by interaction between peridotite and mid-ocean ridge basalt-like melt. The 87Sr/86Sr and 143Nd/144Nd isotopic systematics of clinopyroxenes of the two lherzolites are consistent with MORB-type mantle source. Petrology and light rare earth element (LREE)-depleted patterns of clinopyroxene from the studied lhezolites are the same as those from some of the western Tethyan ophiolites. The age-corrected initial εNd values of the Tethyan lherzolite clinopyroxenes with LREE-depleted patterns are likely to be consistent with the depleted mantle evolution line.

A new subspecies of Momordica cochinchinensis (Cucurbitaceae) from Andaman Islands, India

The middle Andaman Island populations of Momordica cochinchinensis are quite distinct from true M. cochinchinensis in some floral characters. Such deviating specimens are described here as a new subspecies. A full technical description, a morphological comparison between the two subspecies, ecology, phenology, confirmation of genomic distinctiveness through DNA barcoding of matK and rbcL chloroplast loci and viability under cultivation are discussed. An epitype is also designated for Momordica cochinchinensis subsp. cochinchinensis.

Chapter 16 Natural resources

Abstract The natural resources of the Andaman–Nicobar Islands and surrounding seas are discussed. Rocks and minerals found on the Andaman Islands include magnetite, pyrite-chalcopyrite, chromite, gold, nickel, sulphur, coal and limestone, but in most cases their concentrations are sub-economic. Lensoid bodies of algal-biohermal limestones of Palaeogene age on Middle Andaman Island are abundant, accessible and of good grade for cement or foundry work. The Neogene limestones are also suitable for this purpose. Basalts and strongly indurated sedimentary rocks, without any overburden, are quarried for construction work. Limited offshore exploration for oil and natural gas shows great promise, but has yet to be developed.

Chapter 10 Provenance of Oligocene Andaman sandstones (Andaman–Nicobar Islands): Ganga–Brahmaputra or Irrawaddy derived?

Abstract Interpretation of the origin of Oligocene Flysch exposed in the Andaman–Nicobar Islands has been the subject of debate. Previous work on the provenance of the Andaman Flysch based on samples from South Andaman has indicated major contributions from Myanmar affected by the India–Asia collision, mixed with subordinate detritus from the nascent Himalayas. This study examines the provenance of a larger suite of samples that extend to North and Middle Andaman islands as well as Great Nicobar Island. Rather monotonous petrographic and heavy-mineral assemblages testify to strong diagenetic imprint, leading to a poorly constrained identification of the sediment source. U–Pb zircon ages provide more robust and diagnostic provenance discrimination between the Myanmar Arc and the growing Himalayan range. Combining petrographic and mineralogical data with detrital zircon U–Pb analyses, we find that most of the Andaman Flysch is dominated by a strong continental-crust signal with only a minor contribution from arc material. Statistical analyses of the data show that most of the samples have a provenance similar to Palaeogene Bengal Fan sediments, although the type section on South Andaman has a closer affinity to the provenance of the modern Irrawaddy. Supplementary material: Sample location (Table A1), the complete petrographic (Table A2), heavy mineral (Table A3) and U–Pb zircon-age datasets (Table A4) are all available at https://doi.org/10.6084/m9.figshare.c.3634328.v1

The rediscovery of Brownlowia tersa (L.) Kosterm. (Malvaceae), from the Andaman Islands, India — a Near Threatened mangrove species

Brownlowia tersa, described by C.E. Parkinson from the Andaman Islands during the 1920s, was never recollected. The present report concerns its recent collection from North Andaman and Middle Andaman Islands with updated nomenclature, detailed description and distribution notes. It is considered a near threatened species due to habitat loss.

Assessment of trends in morbidity and mortality of the rural population of Rangat, Middle Andaman-A hospital based study

The study was conducted as an attempt to gather information on the diseases prevalent in rural population of Rangat, Middle Andaman Islands. The study was carried out as a hospital based retrospective study by going through the three years viz., 2013, 2014 and 2015 , hospital attendance records of the Community Health Centre Rangat and its five subcentres, Bakuntala, Nimbutala, Sabari, Dasarathpur and Kaushalya Nagar. The data of deaths for the years 2014 and 2015 was also collected from the death register. From the three years data, 28% of the cases were categorized as unclassified and constituted the largest proportion. Communicable and non-communicable diseases constituted almost equal proportions of cases (14%). Hypertensive heart disease was found to be the most common non-communicable diseases present in (47%) cases while among the infectious diseases, cases due to acute respiratory infection (ARI) were(45%) followed by skin infections (20%) and diarrhoeal diseases (14%). Total no. of deaths analysed in 137 adult deaths, 64 (43%) were due the non-communicable diseases, 35(24%) due to senility and 12 (8%) suicide. 25% of the deaths due to non communicable diseases were attributed to Chronic kidney (renal) diseases (CKD). Suicidal deaths were also found to be higher among this population. The findings of the study suggest that Rangat has not remained untouched from epidemiologic transition where there is shift in trend of morbidity and mortality due to chronic non communicable diseases being more common than as due to infectious diseases. As per the findings of the present study, an in depth study is required to be find the prevalence of non communicable diseases ,associated risk factors ,socio behavioural determinants and mental health status in order to plan strategies for prevention and control of non communicable disease and better physical and mental