AN ECOLOGICAL ASSESSMENT OF MAJOR GROUPS OF FAUNAL BIODIVERSITY IN GAHIRMATHA MARINE WILDLIFE SANCTUARY, ODISHA, EAST COAST OF INDIA

Abstract

The present work carried out, under the aegis of project on sea turtle funded by the Wildlife Institute of India, Dehradun that executed in Odisha coast and this project assist to carry out the ecological assessment of different faunal groups in Gahirmatha Marine Wildlife Sanctuary (GMWS) and its adjoining area along the east coast of Odisha, India. The adjoining area is also fallen under the Bhitarkanika Wildlife Sanctuary as it contributes significant biodiversity. A total ten months of field study yields the 338 animal taxa. The relative abundance was estimated for aquatic mammals i.e. the density (Di) of Indian humpback dolphin was 17.6±7.3 per km2 followed by U.2±3 per km2 for finless porpoise and 6.4±2.4 for bottlenose dolphin. The shallow water of Gahirmatha is also support worlds largest amount of Olive Ridley breeding populations. Apart from this, 13 globally threatened avian species were also documented in and adjoining area of the sanctuary. In preliminary assessment it is evident that ecological assessment of faunal biodiversity in particular ecosystem which may help to park manager to implement proper management strategies for protection and conservation of species. Further, extensive research is required to assess the status and distribution of faunal species in the sanctuary.

Headnote

Abstract

The present work carried out, under the aegis of project on sea turtle funded by the Wildlife Institute of India, Dehradun that executed in Odisha coast and this project assist to carry out the ecological assessment of different faunal groups in Gahirmatha Marine Wildlife Sanctuary (GMWS) and its adjoining area along the east coast of Odisha, India. The adjoining area is also fallen under the Bhitarkanika Wildlife Sanctuary as it contributes significant biodiversity. A total ten months of field study yields the 338 animal taxa. The relative abundance was estimated for aquatic mammals i.e. the density (Di) of Indian humpback dolphin was 17.6±7.3 per km2 followed by U.2±3 per km2 for finless porpoise and 6.4±2.4 for bottlenose dolphin. The shallow water of Gahirmatha is also support worlds largest amount of Olive Ridley breeding populations. Apart from this, 13 globally threatened avian species were also documented in and adjoining area of the sanctuary. In preliminary assessment it is evident that ecological assessment of faunal biodiversity in particular ecosystem which may help to park manager to implement proper management strategies for protection and conservation of species. Further, extensive research is required to assess the status and distribution of faunal species in the sanctuary.

Keywords: Biodiversity; Ecological assessment; Fauna; Gahirmatha; Marine; Sanctuary

Introduction

Biodiversity assessment in Protected Areas (PA) is the commonest tool primarily used for conservation of biodiversity in situ which has been recognized under Article 8 of the Convention on Biological Diversity (CBD). As defined in Article-2 of the CBD, Protected Area (PA) is geographically defined area which is designated or regulated and managed to achieve specific conservation objectives. Ecological assessments of the PAs as a strategy for biodiversity conservation indicate that these are extremely important part of the programmes for the conservation of biodiversity and ecosystems. Particularly for fragile environments that require active measures for the survival of certain components or species or biodiversity, ecological assessment is a bare minimum requirement. The PAs also ensures the respect, living treasures, recognition and maintenance of sacred places, cultures and important traditions [1]. The attempt was made to assess the faunal diversity in Gahirmatha Marine Wildlife Sanctuary and adjoining area which is falling under Bhitarkanika Wildlife Sanctuary, one of the best sanctuary and national park with only significant mangroves habitat in the state. Geographical area of India is extent only 2.4% of the total land surface of the world. However, it supports a significant rich diversity of animal fauna about 6.4% of the entire fauna known from the world [2]. India has been internationally acclaimed as mega-biodiversity nation where four Biodiversity Hotspots are present out of 36 identified globally. The State of Odisha located in the east-coast having about 4.74% of the total geographical area of India having unique biogeographical features. The physiography of the Odisha is amalgamation of different biogeographic provinces like Chhotanagpur Plateau, Eastern Highlands, Lower gangetic plain and Eastern-Coastal plain and supports a large diversity of faunal life.

At the present, it is fact that biodiversity or 'the variability of life' is being eroded on a global scale due to various anthropogenic activities [3]. Worldwide loss of biodiversity has worried the people both politically and socially [4], where in situ model of conservation prevailing as a mean to reduce loss of biodiversity [5]. Effective management and conservation of biodiversity is of prime importance. For this purpose, prior information on the abundance, distribution and diversity of species is required so that significant changes could be detected for appropriate management interventions. Hence, a reliable and resourceful procedure is required for the rapid assessment of species abundance and richness for the determination of conservation priorities [6].

Current study was carried out in the prime breeding ground for Olive Ridley Sea Turtles which was also having important aquatic mammals wintering shore birds and adjoin Bhitarkanika area also falling under in an Important Bird and Biodiversity Areas (IBAs) [7]. Many ecological works have been done in GMWS, basically focused on Olive Ridley Turtles. The ecological studies were carried out on Olive Ridley turtles in onshore and offshore area of GMWS by different researchers. The most noteworthy work documented by several workers in this region [8-16]. In biodiversity standpoint, no reasonably assessment of the biodiversity wealth especially of faunal diversity of the Gahirmatha Marine Wildlife Sanctuary has been made till date. The vital information pertaining to available abundance of faunal species and their ecology in the Gahirmatha marine ecosystem is limited due to its remoteness and proximity to prohibited defense establishment (missile test range) which in turn leave a void in significant understanding of faunal biodiversity. The onshore habitat of the marine sanctuary, i.e. outside of protected area was threatened by various unregulated aquaculture activities. Thus, this investigation was carried out to provide an ecological assessment of faunal diversity in Gahirmatha Marine Wildlife Sanctuary as well as adjacent onshore habitat. In the current study, abundance indices or abundance of major faunal groups present in the sanctuary was documented so as to generate baseline information to be implemented in future conservation and management interventions.

Experimental

Study area

The Gahirmatha (Marine) Wildlife Sanctuary of Odisha, India that lies between the mouths of the Dhamra and Barunei Rivers covers 35 km of coast from 20.5049°N, 86.7602°E in the south to 20.7233°N, 87.0701°E in the north. In addition to territorial water area of Bay of Bengal, the sanctuary includes adjoining mangrove reserve forests, accreted beaches and sand bars and mud flats. The Sanctuary consists of 27km2 of land mass area and 1,408km2 area of water body with 725.50km2 core area and 709.5km2 of buffer area (Fig. 1). In order to manage properly, fishing and other derogatory have been either restricted or regulated inside the sanctuary.

Materials and methods

The attempt was made first time to quantify the faunal species akin to mammals, reptiles, amphibians, birds, fishes, molluscs, crustaceans etc. in the sanctuary during 2012 along with offshore Olive Ridley Turtle monitoring project. The following field methods were adopted to quantify individual group of animals in the sanctuary.

Mammals

The line transect method [17-18] was adopted to estimate the abundance of terrestrial mammals in 27 km2 of land mass in the sanctuary. Boat line transect method had also been carried out for aquatic sea mammals in the sanctuary. Five footpaths parallel to coastline was laid in land mass (Mangrove and casuarinas plantations) of the sanctuary to estimate the encounter rate/km of mammalian fauna like wild pig, jackal, hyena, chital, porcupine. Each footpath is approx. 3 km in length (interval of 300 m apart from each other) and each footpath was walked continuous three days and same was carried out every month. Data generated through this observation was used to estimate rate of species encounter (index of abundance) by following formula:

Total number of individual species observed

Total distance (km) covered during that period

The cumulative value of all three walks was obtained for estimation of encounter rate for each species.

Sampling in offshore region was carried by moving on a seaworthy country boat having 9hp onboard engine. Monitoring of sea mammal akin to dolphin, porpoises, whale etc. was carried out in six transects having a stretch of 20 km each at an interval of 1 km parallel to the shore. Transects were determined with the help of GPS (Garmin 72, Garmin Inc.). Average boat speed was minimized to 9km/h to carry out observation for 2.5 to 3 hours in each of the transect.

The parameters which were used to record the existence of potential mammalian species during boat travel and walking included angular sighting distance using laser range finder, animal bearing using compass, individual species, cluster size, etc. The numbers of animals were counted manually after sighting and the distance of sighting was measured. The angle of sighting was measured and adjusted so as to get an angle of 90° to the transect line [20-21]. Visual detection probabilities were modelled as a decreasing function of distance from the transect line. Modelling, estimation of densities of animal and their variances were carried out with the help of 'DISTANCE' programme [22].

Amphibians and Reptiles

Since study area is dominated by the occurrences of Olive Ridley Sea Turtles, their abundance was estimated through the line transect method by moving in boat, in conjunction with the estimation of abundance of sea aquatic mammals [16].

Intensive search (IS) was carried out along the terrestrial transect within a width of 6 m belt. All the microhabitats which included weathered and fallen logs, boulders, grass patches, dense bushes, leaf litters and tree crevices which were within transect line were thoroughly investigated by flushing & beating and overturning logs for amphibians and other reptilian fauna [23].

Birds

Birds were assessed primarily based on field work conducted in the potential sites from March 2012 to December 2012. A total of 242 days were spent in the field observing bird diversity. Birds were observed from 05:30 to 09:00h in morning and 15:30 to 17:30h in evening with the help of spotting scope and 8 x 40 Bushnell binoculars. Shore birds were surveyed in all along the Gahirmatha coast and all major habitats were covered including sand dune region during their wintering season. Surveys were conducted on foot in mangrove forests and agricultural fields while in the river and sea surveys were made with the help of mechanized or non-mechanized boats respectively [24]. The status and frequency of bird sightings have been noted basing on their occurrence. Species diversity indices and species richness were measured based on their frequency of occurrences.

The birds were identified in the field with the help of "Field guide to the birds of the Indian Subcontinent" [25-26].

Fishes

Altogether, fishing data was also collected from the field over a period of ten months similarly. The data were collected in regular interval of seven days from fishing trawlers, gillnetters and traditional fishermen. Fishing data also collected from nearest fishing harbours like Dhamra, Talachua and Paradeep jetties. Specimens were collected and preserved in 4% formalin for identification in the laboratory. The variations in the abundance of species were also estimated. Some of the species were identified and others were examined in the field laboratory with keys for identification as per Talwar and Kacker [27].

Molluscs

The specimens of molluscs were collected twice a month through hand picking method [28] from March 2012 to December 2012 along the shoreline of sanctuary and from the intertidal zone of Ekakula (Sanctuary area). The samples were collected in polythene bags before bringing to the laboratory and sorted out according to species. The specimens were preserved by providing a few drops of 70% alcohol. The shells were air dried then sundried and then kept in separate vials. The snail species were identified as per standard keys and catalogues prescribed in "Fauna of British India" [29] and "Book of Indian Shells" [30].

In additions to the above, two living fossils "Horseshoe crabs" under class Arachnida were enumerated in the area under study. Sampling of Horseshoe crabs were carried out in 'Ekakula' (19° 16'N; 84° 53'E) which is an estuarian ecosystem formed by the tributaries of two major rivers of Odisha State i.e 'Brahmani' and 'Baitarani'. Sampling in this site was done by demarcating a belt transect with 5m width x 900m length symmetric to the river mouth. The transect was further parted into three equal sections enumeration of horseshoe crabs following published protocols [31-33]. The transects were having different habitats. Towards the river mouth it was characteristically sandy, in the middle-mixed sand and mud and muddy sediment at the mangrove fringes. Data on abundance of species were collected fortnightly during full moon and new moon high tides across the study site. Counting of species was done both for live and dead horseshoe crabs washed ashore at an interval of 2-3 days during full moon and new moon. The dead horseshoe crabs were marked on their carapaces with white paint and were dragged up the shore in order to avoid repeated counting during subsequent surveys.

The conservation status of the species provided in the checklist is based on the IUCN Red List, 2016.

Results and discussion

After 10 months of survey and monitoring, 11 species of mammals including terrestrial and aquatic, 38 reptilian species, 11 amphibian species, 149 avifaunal species including shorebirds, 64 species of marine and estuarine fishes, 41 species of molluscs, two species of horseshoe crabs, 16 crab species and 6 shrimp species have been recorded in the study site. Overall faunal assemblage is estimated to be 338 including all groups in the study area. The details ecological analysis of different groups of animals is as follows.

Mammals

During survey period four species of aquatic mammals i.e. dolphins including porpoises were documented in the sanctuary. The relative density of Indo-pacific humpback dolphin (Sousa chinensis) was 17.6/km2 followed by finless porpoises (Neophocaena phocaenoides) 11.2/km2 and bottle nose dolphin (Tursiops aduncus) was 6.4/km2. The overall densities of dolphins were 30.8/km2. One dead washed Irrawaddy dolphin (Orcaella brevirostris) was documented near Habalikhati beach in 2012. The detail results are given in table 1.

Index of abundance of terrestrial mammalian species

As per rates of encounter of different species during survey, highest encounter has been found for jackal (Canis aureus) with mean (±SE) encounter rate of 13±0.62 individuals/km which was followed by wild pig (Sus scrofa) (7.3±0.13 animals/km), chital (Axis axis) (6±0.17 animals/km), porcupine (Hystrix indica) (0.6±0.17 animals/km) and striped hyena (Hyaena hyaena) (0.4±0.11animals/km). The rhesus macaque (Macaca mulata) and smooth-coated otter (Lutrogale perspicillata) were sighted only two times along the footpath; therefore, their index of abundance was not estimated.

Reptiles and amphibians

Simultaneously, the relative densities of Olive Ridley Turtles were estimated through boat line transects along with the population estimation of aquatic mammals in sea. During prenesting season (December to January) the density of turtles were 22.1/km2 followed by 154.4/km2 in nesting season (February to March) and 1.4/km2 in post nesting season (April to May). The overall densities of Olive Ridley Turtles were 78.3/km2 and details are given in table 2.

In addition, hawksbill and green turtles were also occurring in Gahirmatha shallow water. However, during boat line transect their occurrence was minimal only three occasions juvenile hawksbill turtle were encountered and one sub-adult green turtle encountered once in the off Gahirmatha. Therefore, their density was not estimated.

The Asian water monitor lizard (Varanus salvator) frequently seen along the seashore of turtles nesting rookery and mangrove swamps area. The common Indian monitor lizard (Varanus bengalensis) also recorded in the Casuarinas plantation near Satabhaya village. The other reptilian fauna includes Pangshura tentoria, Pelochelys cantorii, Chitra indica, Lissemys punctata, Hydrophis platurus, Enhydrina schistosa, Python bivittatus, Ahaetulla nasuta, Lycodon striatus, Lycodon aulicus, Dendrelaphis tristis, Boiga trigonata, Atretium schistosum, Amphiesma stolata, Ptyas mucosus, Enhydris enhydris, Xenochrophis piscator, Bungarus caeruleus, Bungarus fasciatus, Naja kaouthia, Naja naja, Ophiophagus hannah, Daboia russellii, Trimeresurus gramineus; among lizards Calotes versicolor, Sitana ponticeriana, Lygosoma punctatum, Lygosoma punctata, Hemidactylus leschenaultia, Hemidactylus frenatus, Hemidactylus flaviviridis, Chamaeleo zeylanicus were documented in terrestrial and aquatic mangrove fringe area of sanctuary. One species of crocodiles Crocodylus porosus even recorded in the shallow coast of Gahirmatha Marine Sanctuary, though saltwater crocodile population were abundantly found in different creeks of Bhitarkanika National Park (Table 3).

The species like Grey francolín, Blossom-headed parakeet, Indian cuckoo, Chestnut-headed Bee eater and large cuckoo-shrike were considered as a vagrant species and individual species were documented well outside their normal range. Similarly Eurasian Coot, Crab Plover, Pied Avocet, Grey Plover, Common Snipe, Bar-tailed Godwit, River Tern, Lesser Adjutant, Pallas's Fish Eagle, Brahminy Kite, Osprey, Bar headed geese, Stork-billed Kingfisher, Common Kestrel, Small Pratincole, Oriental Pratincole, Alexandrine Parakeet, Brown Fish-owl, Barn Owl, Orange Headed Ground Thrush, Black Redstart and Eurasian Golden Oriole were considered as rare birds of the area. The frequency and encounter rate of these birds were very unusual and individual populations were recorded very less. However, rest species were believed as a common and uncommon to the area. The 13 species of globally threatened birds were found in the sanctuary including adjacent mangrove area as well as paddy field (Table 6). The percentage of occurrence was estimated for globally threatened birds that found in the sanctuary and average occurrence was 7.7 during the study period. The species diversity index, Shannon Index (H) was calculated to be 4.4 and species richness was estimated 3 in the study area for the period of ten months. The Index value indicates that the structure of bird habitat is stable and balanced.

Ichthyofauna

During this survey 64 species of fishes were recorded from Gahirmatha coast (Table 7). Highest numbers of species were found at Paradeep fishing harbour followed by Dhamra harbour whereas Talachua witnessed a low turnout of species. The most noteworthy feature is that in December maximum numbers of species were recorded along the Gahirmatha coast as well as in three fishing harbor sites. However, in March and April minimum numbers of species were seen i.e. 43% less.

Different fishing gears like trawlers, gill-netters, and country boats were being used for fishing all along the coast. Country Boats were also used by fishermen in three fishing harbour for transportation of fish from river to shore.

Normally two types of nets are being used to catch all types of available fish species in the coast. These were gill net and trawl net. There are three types of Trawl nets: mini high opening shrimp-cum fish trawl net, high opening trawl net and Low opening trawl net. Gill nets and trawl nets are made up of monofilament and multifilament nylon respectively. Gill nets are being used to catch small size fishes whereas trawl nets are used to catch both big and small ones. Mesh size and length of trawl nets are smaller than gill net.

Few groups of fishes were observed in both marine and estuarine water habitats. Their occurrence in both these habitats was restricted to particular season due to their migration from sea to river and vice versa in search of food and to spawn.

Molluscs

Total 41 species of molluscs were recorded along the coast during the study period. Of which nassa mud snail, spindle cone, horn snails, button tops and clams were encountered more in the area followed by others. The list of mollusks was recorded from the sanctuary have given in table 8.

The living fossils "Horseshoe crabs" (Marine arachnids)

Total 5,025 specimens of Tachypleus gigas (live and dead) and 601 individuals Carcinoscorpius rotundicauda were recorded from Ekakula during the study. Sighting frequency of horseshoe crabs during the new and full moon phase were statistically similar for Tachypleus gigas (t = -0.320, p = 0.579) and Carcinoscorpius rotundicauda (t = 0.624, p = 0.431). However, sighting of both the species was less in winter season. It is a matter of concern to observe more dead individuals than alive during the period of study where dead individuals accounted for 95.3 and 92.5% for Tachypleus gigas and Carcinoscorpius rotundicauda respectively. Only 63 live Tachypleus gigas with 20 males and 43 females and 21 live Carcinoscorpius rotundicauda with 15 males and 6 females were recorded.

Although the abundance of horseshoe crabs at Ekakula, varied among the transects over time, the mean density of live and dead Tachypleus gigas and Carcinoscorpius rotundicauda was 1.16 and 0.11 individuals/m2 respectively. Sighting was highest in the summer season (April-June) for both species. In addition to this, the group decapods crustaceans including Ocypode macrocera, Ocypode ceratophthalma, Ocypode brevicornis, Matuta victor, Doclea rissonii, Scylla olivacea, Scylla tranquibarica, Portunus pelagicus, Portunus sanguinolentus, Charybdis feriata, Metopograpsus latifrons, Metopograpsus messor, Metaplax distinct, Uca rosea, Uca triangularis, and Uca annulipes were documented and among shrimps Melicertus canaliculatus, Metapenaeopsis stridulans, Metapenaeus affinis, Metapenaeus brevicornis, Total 16 species of crabs and six species of shrimps were listed that includes occurrence in inter-tidal area, benthic and pelagic habitat of the sanctuary.

Ecological assessment is a process for identifying and quantifying the number of species occurrence in an ecosystem and providing a scientifically justifiable approach to ecosystem management. Odisha, with its unique bio-geographic features like the Chhotanagpur Plateau, Eastern Highlands, Lower Gangetic Plains and Eastern Coastal Plains supports a large diversity of faunal assemblage in the state. The high faunal diversity is attributed to a large number of estuaries, coastal ecosystems, rivers and the presence of many pristine forests with high mountains.

Out of six hundred fifty-six globally threatened faunal species in India, sixty-nine (10% of India) distributed in Odisha, comprising 16 critically endangered, 21 endangered and 32 vulnerable categories. The faunal diversity of Odisha was recently compiled based on available data, new discoveries and comprises 114 species of mammals (103 wild and 11 domestic mammals), 537 avifaunal species, 131 reptilian species, 29 amphibian species, about 800 fish species and thousands of other invertebrates [34].

The Gahirmatha marine wildlife sanctuary and its neighboring area were found to support 338 faunal species which is very significant in relevance to species for the conservation and management of biological diversity of that particular site. The river Brahmani and Baitarani forms a large estuary and opening at the sanctuary and also many small river and rivulets opens to the Gahirmatha sanctuary, which provides more diversified habitats for large amount of faunal diversity. Generally, the global or continental diversity is well described by the abundance or richness of species [35], whereas regional or landscape diversity is less well described [36] and local diversity is often poorly described [37, 38]. The abundance and distribution of most faunal species may vary temporarily in relation to daily, seasonal or long-term cycles or fluctuations in their environments. This variation indicates the presence of greater genetic diversity and the diversity of communities to which the species belongs. Thus, sampling and observation of various faunal groups should be undertaken in day or night and in the seasons of highest activity. However, in present study the assessment of faunal species was undertaken for ten months merely. In this view, the random sampling was adopted for different groups of animals residing in the study site. In other case, expertise of the observer to record the species during ecological assessment of the faunal diversity is very important. Particularly in case of amphibians and birds the expertise and experience of the observer becomes very crucial for the identification of species with specific calls, and behavior. In the case of mammals, it is very important to identify from indirect evidence such as scats, droppings, pugmarks, footprints, scrape and feeding signs, etc.

Inventories of species are used in wide contexts and can be analyzed in many different views. As previous study states, "Look at species lists in a standard ecological paper and check how accurate are the data sets that, often, are analyzed with the most robust statistical analysis" [39]. In a given time window, no continuous sampling was done for faunal assessment in the sanctuary, it could have a greater number of species variations if the long-term monitoring of faunal biodiversity is allowed there. However, repeated surveys provide Long-term monitoring of faunal biodiversity is required to get basic information on the seasonal, annual and other cyclical changes and also to obtain detailed ecological assessment of rare, endangered, threatened or uncommon species in a particular location [40]. However, these are very cumbersome and expensive activities.

Gahirmatha is dignified to be the largest mass nesting rookery for Olive Ridley Sea Turtles in the world [41, 42]. The coastal water of Gahirmatha was declared as wildlife sanctuary in September 1997 to protect the Olive Ridley Sea Turtles in both nesting beaches and in near-shore habitats. Conservation measures need to be taken up for safeguarding of the offshore congregation sites of the turtles. For this purpose, generation of base level information on the abundance and distribution of Olive Ridley Turtles in offshore water of Gahirmatha marine sanctuary is very much important. Off rookery congregations or "reproductive patch" of the turtles are observed up to a distance of 5-7km from the seashore, hence, such sites need to be identified and effective protection measures need to be taken up to protect the breeding turtles in a targeted manner with effective use of available resources. This is very much necessary to avoid guarding large number of spatial entities which may or may not be active in turtle habitats. Various studies have indicated the dynamic nature of the congregation patches in the breeding season of turtles. Hence, conservation measures need to be based on area specific rather than time specific in offshore for Olive Ridleys at Gahirmatha rookery or elsewhere in the world. Such reproductive patches need to be identified in every breeding season and demarcated with floats. Gahirmatha area encounters large number of fishing activities, incidental capture of Olive Ridley turtles occurs in trawl fisheries, longline fisheries, gill net and other net fisheries. As a major threat to this species in this site, intensive patrolling need be carried out in these potential sites to prevent any harmful fishing activities. Participatory approach to management which includes awareness, dialogues, discussions with various organizations, local fishermen and other stakeholders to get cooperation and coordination, has been highly stressed for this purpose [14].

Monitoring faunal biodiversity studies are of great significance in the ecological estimation of living resources occurring in distinct geographical locations of the world, defining extension of protected areas and documenting local extinctions or invading species for inferring impeding impact as well as assessment of environmental interferences [43]. In this context, the mammals, amphibians, reptiles, avifauna, fishes, mollusks, crustaceans, arthropods (arachnids) are important, as a number of species were documented in the sanctuary as well as adjoining Bhitarkanika area and an incredible assortment of little forms contributes to the complexity and function of ecosystems. The sanctuary area potentially rich in fisheries resources and three fishing harbours mostly depends on these sites for fishing. Therefore, fishing resources data have been obtained from these three harbours and other sources. The information on some crustacean species like Ocypode macrocera, Ocypode ceratophthalma, Ocypode brevicornis, Matuta victor, Doclea rissonii, Scylla olivacea species occurring in the study site have been confirmed (As per personal interaction with Dr. Anil Mahapatra).

With the purpose to develop a feasible conservation policy for horseshoe crabs, there is an urgent need of action which need to include sensitization of local law enforcement agencies like Forest Department. Effective implementation of monitoring protocols across the vulnerable intertidal areas of the Gahirmatha coast will further strengthen the conservation. Involvement of local fishermen and non-government organizations (NGOs) motivated for conservation are important part for this purpose. More particularly the activation of the fishing community only may fulfil major part of the purpose to conserve the horseshoe crabs. As the current study revealed the occurrence of great number of dead crabs along the stretch of coast and in spawning grounds, mass awareness programmes need be initiated to highlight the local conservation of horseshoe crabs [33]. Similarly, trained bird watchers may be deployed in the study area during annual bird census programme to confirm the accurate species and avian diversity. Odisha coast harbors 11 species of dolphins and one species porpoise, however, during this present study documented three species of dolphins and one porpoise in the sanctuary area. As previous study, the other dolphins are inhabited with deep or coastal water in Odisha coast [44]. Many threatened fish species documented in this study and those species export to neighbor states through the nearest fishing harbour. Therefore, fishing harbour close to the study sites need monitor properly and should aware them to on threatened category species, not to catch those species, if accidentally caught, release back to sea immediately and these to be carried out through public participations. Rampant trawl fishing, standing net and aquaculture practice in near shore area major threats to the faunal biodiversity.

Conclusions

The sanctuary and adjacent area harbours the major faunal species and these areas need to be monitored properly. Consequently, it is extremely necessary for ecological assessment of faunal biodiversity in particular ecosystem which may help to park manager to implement proper management strategies for protection and conservation of various species before they undergone. Further, a comprehensive study in this site is required to explore details on the distribution and status of various faunal groups in this important marine sanctuary.

Acknowledgments

Authors are grateful to the PCCF Wildlife & Chief Wildlife Warden, Odisha for allowing the researchers to carry out this investigation. Authors are also grateful to the Director & Dean, Wildlife Institute of India, Dehradun, India. Special thanks to Prof. B. C. Choudhury and Dr. K. Sivakumar for providing opportunity to work in such a varied coastal ecosystem. Authors are grateful to the Chairman/Member Secretary, Odisha Biodiversity Board, Bhubaneswar. We are grateful to all the field staffs for their assistance in the field.

Sidebar

Received: August 19, 2020 Accepted: October 20, 2021

References

References

[1] D. Harmon, A.D. Putney, The Full Value of Parks: From Economics to the Intangible, Rowman and Littlefield, New York, NY, 2003, p. 360.

[2] K. Chandra, C. Raghunathan, T. Mondal, S. Dash, Current Status of Marine Faunal Diversity in India, Published by the Zoological Survey of India, Kolkata, 2016, p. 525.

[3] H.M. Pereira, P.W. Leadley, V. Proença, R. Alkemade, J.P. Scharlemann, M.B. Fernandez-Manjarrés et al., Scenarios for global biodiversity in the 21st century, Science, 330(6010), 2010, pp.1496-1501.

[4] S. Lele, P. Wilshusen, D. Brockington, R. Seidler, K. Bawa, Beyond exclusion: alternative approaches to biodiversity conservation in the developing tropics, Current Opinion in Environmental Sustainability, 2(1), 2010, pp. 1 -7.

[5] G. Eken, L. Benun, T.M. Brooks, W. Darwall, L.D.C. Fishpool et al., Key biodiversity areas as site conservation targets, Bioscience 54(12), 2004, pp.1110-1118.

[6] L. Silviera, T.A. Jacomo Anah, J.A.F. Diniz-Filho, Camera trap, line transect census and track surveys: a comparative evaluation, Biological Conservation, 114(3), 2003, pp. 351 - 355.

[7] A.R. Rahmani, M.Z. Islam, R.M. Kasambe, Important Bird and Biodiversity Areas in India: Priority Sites for Conservation (Revised and updated), Bombay Natural History Society, Indian Bird Conservation Network, Royal Society for the Protection of Birds and BirdLife International (U.K.), 2016, 1992 + xii.

[8] M.C. Dash, C.S. Kar, The Turtle Paradise: Gahirmatha, Interprint, New Delhi, 1990, p. 295.

[9] B. Pandav, B.C. Choudhury, Conservation and management of Olive Ridley Sea Turtle (Lepidochelys olivacea) in Orissa, Project Final Report, Wildlife Institute of India, Dehradun, 2000, p. 77.

[10] B. Pandav, Conservation and Management of Olive Ridley Sea Turtle (Lepidochelys olivacea) along the Orissa coast, Ph.D. Thesis, Utkal University, Orissa, 2000, p. 106.

[11] K. Ram, Behavioral Ecology of the Olive Ridley Sea Turtle Lepidochelys olivacea (Eschscholtz, 1827) during the breeding period, Masters' Dissertation, Salim Ali School of Ecology, Pondicherry University, India, 2000, p. 60

[12] G. Prusty, S. Dash, M.P. Singh, Spatio-temporal analysis of multi-date IRS imageries for turtle habitat dynamics characterization at Gahirmatha coast, India, International Journal of Remote Sensing, 28(5), 2007, pp. 871-883.

[13] S. Behera, Ecology and distribution pattern of Olive Ridley Sea Turtles Lepidochelys olivacea at Gahirmatha rookery of Orissa Coast, India, Ph.D Thesis, North Orissa University, Odisha, India, 2012, p. 208.

[14] S. Behera, B. Tripathy, K. Sivakumar, B.C. Choudhury, B. Pandav, Fisheries impact on breeding of olive ridley turtles (Lepidochelys olivacea) along the Gahirmatha coast, Bay of Bengal, Odisha, India, Herpetological Journal, 26(2), 2016, pp. 93-98.

[15] S. Behera, B.C. Choudhury, S.K. Dutta, Spatial Dynamics of Olive Ridley Turtles (Lepidochelys olivacea) Density in the Tropical Sea Water of India, Proceedings of the Zoological Society 72, 2018, pp. 364-371. DOI: 10.1007/s12595-018-0277-8.

[16] S. Behera, B. Tripathy, K. Shivakumar, B.C. Choudhury, S.K. Dutta, B. Pandav, Nesting Space Dynamics and its Relationship with the Arribada of Olive Ridley Turtles at Gahirmatha Rookery, East Coast of India, Journal of Herpetology, 52(4), 2018, pp. 381 - 386.

[17] K.P. Burnham, D.R. Anderson, J.L. Laake, Estimation of density from line transect sampling of the biological populations, Wildlife Monograph, 72(3), 1980, pp. 1-202.

[18] S.T. Buckland, D.R. Anderson, K.P. Burnham, J.L. Laake, Distance Sampling: Estimating Abundance of Biological Populations, Chapman & Hall, London, 1993, p. 446.

[19] W.J. Sutherland, Ecological Census Techniques: A Handbook, Cambridge University Press, Cambridge, U.K, 1996, pp. 1-9.

[20] S.T. Buckland, D.R. Anderson, K.P. Burnham, J.L. Laake, D.L. Borchers, L. Thomas, Introduction to Distance Sampling, Oxford: Oxford University Press, 2001, pp. 260-280.

[21] L. Thomas, K.U. Karanth, Monitoring tigers and their prey: a manual for researchers, managers and conservationists in Tropical Asia, (Editor K.U. Karanth, J.D. Nichols) Centre for Wildlife Studies, Bangalore, India, 2002, pp. 121-138.

[22] L. Thomas, S.T. Buckland, E.A. Rexstad, J.L. Laake, S. Strindberg, S.L. Hedley et al., Distance software: design and analysis of distance sampling surveys for estimating population size, Journal of Applied Ecology, 47(1), 2010, pp. 5-14.

[23] B.K. Koirala, K. Cheda, T. Penjor, Species diversity and spatial distribution of amphibian fauna along the altitudinal gradients in Jigme Dorji National Park, western Bhutan, Journal of Threatened Taxa, 11(3), 2019, pp. 14249-14258

[24] G.V. Gopi, B. Pandav, Avifauna of Bhitarkanika Mangroves, India, Zoos' Print, 22(10), 2007, pp. 2839-2847.

[25] R. Grimmett, C. Inskipp, T. Inskipp, Pocket Guides to the Birds of the Indian Subcontinent, Cristopher Helm Publishers, Oxford University Press, 2001, p. 384.

[26] S. Ali, S.D. Ripley, A Pictorial Guide to the Birds of the Indian Subcontinent, Bombay Natural History Society, Oxford University Press, India, 1983.

[27] P.K. Talwar, R.K. Kacker, Commercial Sea fishes of India, Zoological Survey of India, 1984, p. 997.

[28] D.L. Geiger, B.A. Marshall, W.F. Ponder, T. Sasaki, A. Warén, Techniques for collecting, handling, preparing, storing and examining small molluscan specimens, Molluscan Research, 27(1), 2007, pp. 1-50.

[29] H.B. Preston, The Fauna of British India, Mollusca, Taylor and Francis, London, 1915, pp. 244.

[30] D.A. Apte, Book of Indian Shells, Bombay Natural History Society, Oxford University Press, India, 1998, p. 191.

[31] L. Cartwright-Taylor, J. Lee, C.C. Hsu, Population structure and breeding pattern of the mangrove horseshoe crab Carcinoscorpius rotundicauda in Singapore, Aquatic Biology, 8(1), 2009, pp. 61-69.

[32] L. Cartwright-Taylor, V.B. Yap, C.C. Hsu et al., Distribution and abundance of horseshoe crabs Tachypleus gigas and Carcinoscorpius rotundicauda around the main island of Singapore, Aquatic Biology, 13(2), 2011, pp. 127-136.

[33] S. Behera, B. Tripathy, K. Sivakumar, B.C. Choudhury, P. Bhadury, Distribution and Abundance of Two Sympatric Species of Horseshoe Crabs Along the Odisha Coast, India, Changing Global Perspectives on Horseshoe Crab Biology, Conservation and Management, (Editor: R.H. Carmichael et al.), DOI 10.1007/978-3-319-19542-1_9, 2015, p. 599.

[34] S. Behera, P.P. Mohapatra, S.K. Dutta, Turtles and Tortoises of Odisha, Published by Odisha Biodiversity Board, Forests and Environment Department, Government of Odisha, 2019, p. 120.

[35] N. Myers, R.A. Mittermeier, C.G. Mittermeier, G.A.B. Fonseca, J. Kent, Biodiversity hotspots for conservation priorities, Nature, 403(6772), 2000, pp. 853-858.

[36] H. Gomez de Silva, R.A. Medellin, Evaluating completeness of species lists for conservation and macroecology: A case study of Mexican land birds, Conservation Biology, 15(5), 2001, pp. 1384-1395.

[37] R.A. How, Long-term sampling of a herpetofaunal assemblage on an isolated urban bushland remnant, Journal of the Royal Society of Western Australia, 81(3), 1998, pp. 143-148.

[38] G.G. Thompson, P.C. Withers, E.R. Pianka, S.A. Thompson, Assessing biodiversity with accumulation curves; inventories of small reptiles by pit-trapping in Western Australia, Australian Ecology, 28(4), 2003, pp. 361-383.

[39] F. Boero, Light after dark: the partnership for enhancing expertise in taxonomy, Trends in Ecology and Evolution, 16(5), 2001, p. 266.

[40] R.A. How, N.K. Cooper, Terrestrial small mammal fauna of the Abydos Plain in the northeastern Pilbara, Western Australia, Journal of the Royal Society of Western Australia, 85(2), 2002, pp. 71 -82.

[41] H.R. Bustard, World's largest sea turtle rookery? Tiger Paper, 3(3), 1976, pp. 25.

[42] S. Behera, H. Kaiser, Threats to the nests of Olive Ridley Turtles (Lepidochelys olivacea Eschschholtz, 1829) in the world's largest sea turtle rookery at Gahirmatha, India: need for a solution, Herpetology Notes, 13, 2020, pp. 435-442.

[43] D.U. Hooper, F.S. Chapin, J.J. Ewel, A. Hector, P. Inchausti, S. Lavorel, Lawton et al., Effects of Biodiversity on Ecosystem Functioning: A Consensus of Current Knowledge, Ecological Monographs, 75(1), 2005, pp. 3 -35.

[44] M. Khan, S. Panda, S.S. Srivastava, Whales, Dolphins and Porpoises of Odisha, Published by Wildlife Organization, Forests and Environment Department, Government of Odisha, 2015, p. 162.