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We have theoretically investigated nine unusual isomers of the molecular formula C5H4 using coupled cluster (CC) and density functional theory (DFT) methods. These molecules possess non-classical structures consisting of two pyramidanes, three planar tetracoordinate carbon (ptC), and four spiro types of isomers. Both the pyramidanes (tetracyclo-[2.1.0.01,3.02,5]pentane; py-1 and tricyclo-[2.1.0.02,5]pentan-3-ylidene; py-2) are minima on the potential energy surface (PES) of C5H4. Among the three isomers containing ptC, (SP4)-spiro [2.2]pent-1-yne (ptC-2) is a minimum, whereas isomer, (SP4)-spiro [2.2]pent-1,4-diene (ptC-1) is a fourth-order saddle point, and (SP4)-sprio[2.2]pent-1,4-diylidene (ptC-3) is a transition state. The corresponding spiro isomers spiro[2.2]pent-1,4-diene (spiro-1), sprio[2.2]pent-1,4-diylidene (spiro-3) and spiro[2.2]pent-4-en-1-ylidene (spiro-4) are local minima, except spiro[2.2]pent-1-yne (spiro-2), which is a second-order saddle point. All relative energies are calculated with respect to the global minimum (pent-1,3-diyne; 1) at the CCSD(T)/cc-pVTZ level of theory. Quantum chemical calculations have been performed to analyze the bonding and topological configurations for all these nine isomers at the B3LYP/6-311+G(d,p) level of theory for a better understanding of their corresponding electronic structures. ptC-2 was found to be thermodynamically more stable than its corresponding spiro counterpart (spiro-2) and possesses a high dipole moment (μ = 4.64 D). The stability of the ptC structures with their higher spin states has been discussed.

Expansion of aquaculture in the Sundarbans Biosphere Reserve (SBR) is irreversibly replacing agricultural land and the drivers of this change are disputed. Based on in-depth interviews with 67 aquaculture farmers, this paper characterizes major aquaculture types in the SBR, their impacts, and identifies drivers of conversion from agricultural land. Aquaculture types included traditional, improved-traditional, modified-extensive, and semi-intensive systems. Extensive capture of wild shrimp larvae is environmentally harmful but constitutes an important livelihood. Semi-intensive aquaculture of exotic shrimp (Litopenaeus vannamei) has much higher unit-area profitability than other types but involves greater financial risk. Profitability is the main driver for the transition from agriculture, but environmental factors such as lowered crop yields and cyclone impacts also contributed. Many conversions from agriculture to aquaculture are illegal according to the stakeholders. Existing legislation, if enforced, could halt the loss of agriculture, while the promotion of improved-traditional aquaculture could reduce the demand for wild seed.

This investigation characterized the relationship between percentage occurrences of three size classes of Hilsa juveniles (3–5, 5.1–10, and 10.1–15 cm) and six biogeochemical parameters (water temperature, chlorophyll-a, turbidity, salinity, dissolved oxygen, and pH) in the lower part of the tidal riverine to the entire estuarine stretch of Hooghly. These relationships helped us determine the ranges of each biogeochemical parameter for different suitability criteria in three seasons, pre-monsoon (February–May), monsoon (June–September), and post-monsoon (October–January). Salinity had the highest weight (0.37–0.39) followed by chlorophyll-a (0.26–0.30) and turbidity (0.12–0.20). The geospatial data of the biogeochemical parameters were interpolated followed by reclassification with the suitability ranges, separately for each season. These reclassified data were integrated into GIS-based modeling by a multi-criteria decision-making technique (analytical hierarchy process) to generate the habitat suitability maps of juvenile Hilsa. The model-derived information was verified with the indigenous knowledge of the fishers regarding the suitable habitat of juvenile Hilsa by conducting group discussions at 13 locations along the entire study area. The degree of agreement/disagreement between the model and the field information was determined by measuring Kendall’s tau (0.81–0.96) and Kappa coefficients (0.77–0.86), which indicated a strong agreement. In total, 3.80%, 10.12%, and 31.08% of the total river-estuarine area considered for the present study were identified as highly suitable for juvenile Hilsa during pre-monsoon, monsoon, and post-monsoon seasons, respectively. This mapping can act as baseline information for the policymakers for sustainable Hilsa fishing keeping in view the livelihood of fishers.

Application of remote sensing makes the assessment and monitoring of mangroves both time and cost-effective. In this study, the capacity of AVIRIS-NG data in discriminating different mangrove species of Lothian Island of Indian Sundarbans has been evaluated and compared with hyperspectral (Hyperion) and multispectral dataset (Landsat 8 OLI and Sentinel-2). Spectral signatures of mangrove species were retrieved, and spectral libraries were created. With the corrected images and spectral libraries, mangroves were classified using appropriate classification techniques. For multispectral datasets (Landsat 8 OLI and Sentinel-2) and hyperspectral coarser-resolution Hyperion datasets, K-means classification followed by knowledge-based classification was adopted. For fine resolution hyperspectral AVIRIS-NG dataset, classification was accomplished using Support Vector Machine (SVM). The overall accuracy for the classification is significantly high in case of AVIRIS-NG data (87.61%) compared to the Landsat 8 OLI (76.42%), Sentinel-2 (79.81%), and Hyperion data (81.98%). The results showed that AVIRIS-NG hyperspectral dataset has the potential to classify not only the genus level but also species-level with satisfactory accuracy in a complex mangrove forest.

Indian Sundarbans Biosphere Reserve (SBR) comprising over 100 estuarine islands and shared by human habitation and mangrove forests is considered to be a potential area for coastal aquaculture. This study, using LANDSAT imageries of the last two decades (1999–2019), delineated the spatiotemporal expansion of aquaculture at the expense of agricultural land, mudflats, and some mangroves. It also estimated a futuristic land transformation to aquaculture using the Cellular Automata-Markov Chain model. From the geospatial analysis, it is observed that (1) the aquacultures are mostly located around 22° 30′N, i.e., far away from the saline seafront, (2) total aquaculture area has increased to nearly 5.82% of the entire SBR in 2019 from 3.59% in 1999 and, (3) cyclone Aila and its surge inundation have influenced in their expansion. This growth of aquaculture took place with the loss of 3.71% (10,536.67 ha) agricultural land, 3.87% (730.40 ha) mudflat, and 0.28% (623.23 ha) mangrove from 1999 to 2009, and 6.02% (13,471.50 ha) agricultural land, 9.98% (1583.64 ha) mudflat, and 0.18% (382.35 ha) mangrove during 2009–2019. According to the predictive modeling, ~ 6% of the present agriculture area is prognosticated to be converted to aquaculture by the next decade under a business-as-usual scenario.

Adrenal myelolipomas are uncommon tumours of unknown aetiology. They arise from the adrenal cortex and comprise lipomatous and myeloid elements. They are considered to be functionally inert, and metabolic evaluation is not mandatory for them. Adrenal myelolipomas can rarely be functionally active, and patients may present with hypertension, electrolyte imbalance or features of Cushing's syndrome. The association of these tumours with catecholamine secretion is exceptionally rare. We describe a case of a functional adrenal myelolipoma associated with catecholamine secretion in a 55-year-old female patient with a history of hypertension. The surgical excision of the mass resulted in normalisation of the urinary catecholamine levels and resolution of the hypertension.

Aquaculture practices are steadily increasing to meet the fish demand, especially in tropical countries like India. However, efforts to characterize the contribution of these aquaculture ponds towards greenhouse gas emission like CH4 are still very few. CH4 concentration in water [pCH4(water)] and air–water CH4 fluxes were estimated (during the summer months) in two sewage-fed ponds having different depths situated in the East Kolkata Wetlands, India (a Ramsar site). pCH4(water) in both of these ponds showed significant positive correlation with water temperature (R2 = 0.68 and 0.71, p

Tide and lunar phases often influence the behaviour and life cycle of different fishes, especially migratory species. In the Hooghly River estuary, Hilsa shad is an anadromous fish species that migrates from the adjacent sea to the estuary and rivers for spawning. After spawning, the juveniles remain in the rivers and estuary for few months then start their downstream migration towards the adjacent sea. However, the pattern of their downstream migration has not been studied in detail so far. This study investigates the role of tide and lunar phases on the juvenile Hilsa shad migration pattern. In this study, we have estimated the rate of juveniles migrating through the river channel (no. m

Liposarcoma is an uncommon group of tumors in the pediatric population. Of the various known subtypes,pleomorphic liposarcoma is the most infrequent in children.We present the case of a 7-year old child coming to the radiology department for evaluation of a right knee swelling. Plain radiograph and corresponding MRI images showed features of primary bone tumor possibly Ewing’s sarcoma in right distal femur. The child developed right shoulder pain and CT thorax abdomen was done which revealed retroperitoneal mass with hepatic and pulmonary metastases.Subsequent core needle biopsy from the femur confirmed metastatic liposarcoma with pleomorphic features, extremely rare in childhood.The very rare incidence of metastasis that too presenting as a common primary tumor the misdiagnosis of which could result in catastrophic fate. So it’s of prime importance that clinicians should be aware of this entity. Keywords: FISH; liposarcoma; myxiod dedifferentiated liposarcoma; pleomorphic liposarcoma; softsarcoma

Reproduction and distribution patterns of Sardinella fimbriata had responded differently to oceanographic changes in various parts of the world. This is the first report investigating the effects of oceanographic parameters on the maturation and spawning of S. fimbriata in the northern part of Bay of Bengal. Monthly precipitation rate, sea surface temperature (SST) and chlorophyll-a data were analyzed for possible correlation with Catch per Unit Effort (CPUE) of the fish species under study. Gonado-somatic Index, Gastro-somatic Index, and histology of the gonadal maturity stages were also studied. The peak spawning activity was found to take place during the period with the highest precipitation rate (r2 = 0.5006, p

Partial pressure of CO2 in water [pCO2(water)] and air-water CO2 flux were estimated in two aquaculture ponds (one received no lime treatment (NTP) and in the other lime treatment was performed (LTP) four times a year) every month throughout an annual cycle, situated in East Kolkata Wetlands, a Ramsar Site in eastern India. It was hypothesized that lime treatment can potentially lower the pCO2(water) in aquaculture ponds and hence make these aquatic bodies sinks for CO2. The results portrayed that NTP acted as a source of CO2 throughout the year (annual mean: 1929 ± 1397 μmol m−2 h−1), whereas, LTP acted as CO2 sinks post lime addition (monthly mean ranged from −366 ± 16 to −449 ± 32 μmol m−2 h−1), though the effect of lime addition was found to diminish by the next month and it acted as source for CO2 in the months when no lime treatment was done (LTP annual mean: 1010 ± 1617 μmol m−2 h−1). Lime treatment increased the pH level and reduced the turbidity which facilitated optimum photosynthesis and the productivity increased rapidly. Beyond the critical pH value of 8.9–9.0, the pCO2(water) values became under-saturated with respect to atmospheric CO2 concentration. The effect of lime treatment was not found to prevail in the following months as a steady source of sewage from the Kolkata metropolis which feeds these aquaculture constantly bring in a huge carbon source both in inorganic and organic form. As soon as the flocculation effect of the lime dies off, the water column starts becoming turbid again which aids in converting the system into a net heterotrophic one from a net autotrophic. Based on the results we could successfully accept our hypothesis that lime treatment can not only reduce the CO2 emission but also make the system a CO2 sink.

Land in the Indian Sundarbans Biosphere Reserve (SBR) has been extensively (and illegally) converted from agriculture to aquaculture over the last two decades, with implications for Sustainable Development Goals addressing food, poverty, employment, terrestrial and marine ecosystems and inequality. The economic returns from aquaculture are higher than agriculture, but more unequally shared, demand for labour is lower (and often fullfilled by non-local workers) and the expansion of brackish water aquaculture, in particular can contribute to the salinization of land through seepage from ponds, and intentional water management to bring saline water to farms. While remote sensing can demonstrate the conversion, the drivers behind are less clear. Much literature, along with commonly articulated stakeholder perspectives strongly suggest that sea-level rise and cyclone impacts lead to salinization, resulting in reduced agricultural productivity, leading farmers to convert to saline aquaculture as an adaptation. However, this is unclear in the Indian Sundarbans where the highest rates of conversion are not in areas which have suffered saline inundation. SBR-wide factors that affect rates of conversion include international demand for prawns, technology development and transfer, availability of seed, legal frameworks and land tenure. At a more local level, connectivity (for inputs and for marketing product), proximity to water sources, levels of cyclone inundation, salinity and agricultural productivity, existing aquaculture areas, extension services and local government (dis)incentives may explain spatial patterns of differing conversion rates. In this paper we use a two-decade long timeseries of remotely sensed data on land cover and agricultural productivity along with spatially explicit data on connectivity to evaluate which factors were most associated with conversion from agriculture to aquaculture in the past two decades. We then project future possible conversion based on scenarios of how these drivers may change over the the next decade and discuss their implications for Sustainable Development Goals.

The United Nations Sustainable Development Goals (SDGs) and their corresponding targets are significantly interconnected, with many interactions, synergies and trade-offs between individual goals across multiple temporal and spatial scales. We propose a framework for the Integrated Assessment Modelling (IAM) of a complex deltaic socio-ecological system in order to analyse such SDG interactions. We focus on the Sundarbans Biosphere Reserve (SBR), India within the Ganges-Brahmaputra-Meghna Delta. It is densely populated with 4.4 million people (2011), high levels of poverty and a strong dependence on rural livelihoods. It is only 50 km from the growing megacity of Kolkata (about 15 million people in 2020). The area also includes the Indian portion of the world’s largest mangrove forest – the Sundarbans – hosting the iconic Bengal Tiger. Like all deltaic systems, this area is subject to multiple drivers of environmental change operating across different scales. The IAM framework is designed to investigate current and future trends in socio-environmental change and explore associated policy impacts, considering a broad range of sub-thematic SDG indicators. Integration is achieved through the soft coupling of multiple sub-models, knowledge and data of relevant environmental and socio-economic processes. The following elements are explicitly considered: (1) agriculture; (2) aquaculture; (3) mangroves; (4) fisheries; and (5) multidimensional poverty. Key questions that can be addressed include the implications of changing monsoon patterns, trade-offs between agriculture and aquaculture, or the future of the Sundarbans mangroves under sea-level rise and different management strategies, including trade-offs with land use to the north. The novel high-resolution analysis of SDG interactions allowed by the IAM will provide stakeholders and policy makers the opportunity to prioritize and explore the SDG targets that are most relevant to the SBR and provide a foundation for further integrated analysis.

The United Nations Sustainable Development Goals (SDGs) and their corresponding targets are significantly interconnected, with many interactions, synergies, and trade-offs between individual goals across multiple temporal and spatial scales. This paper proposes a framework for the Integrated Assessment Modelling (IAM) of a complex deltaic socio-ecological system in order to analyze such SDG interactions. We focused on the Sundarban Biosphere Reserve (SBR), India, within the Ganges-Brahmaputra-Meghna Delta. It is densely populated with 4.4 million people (2011), high levels of poverty, and a strong dependence on rural livelihoods. It is adjacent to the growing megacity of Kolkata. The area also includes the Indian portion of the world’s largest mangrove forest––the Sundarbans––hosting the iconic Bengal Tiger. Like all deltaic systems, this area is subject to multiple drivers of environmental change operating across scales. The IAM framework is designed to investigate socio-environmental change under a range of explorative and/or normative scenarios and explore associated policy impacts, considering a broad range of subthematic SDG indicators. The following elements were explicitly considered: (1) agriculture, (2) aquaculture, (3) mangroves, (4) fisheries, and (5) multidimensional poverty. Key questions that can be addressed include the implications of changing monsoon patterns, trade-offs between agriculture and aquaculture, or the future of the Sundarbans’ mangroves under sea-level rise and different management strategies. The novel, high-resolution analysis of SDG interactions allowed by the IAM will provide stakeholders and policy makers the opportunity to prioritize and explore the SDG targets that are most relevant to the SBR and provide a foundation for further integrated analysis.

The coral reefs of Andaman Islands with an area of 948.8 km2 have an affinity to the South-East Pacific Coral Triangle in terms of species diversity. These reefs are of fringing; channel and patch types with 588 species of hard corals. The paper reviews the diversity and status of reefs in the north, middle and south Andaman and with the help of Remote Sensing and GIS mapped the various events that are threatening the health of these reefs. The mass coral bleaching event induced by sea surface temperature (SST) anomalies coupled with the El Nino Southern Oscillation (ENSO) phenomena in 2010 led to a loss of almost 70% of live coral in the South Button Island, Havelock Island, North Bay, Chidiyatapu and Redskin Island. Between 28th March and 30th April 2016, in-situ temperatures of 31.80 ° C to 32.30 ° C were reported at North Bay leading to bleaching of Acropora fungoid. The crustal upliftment and crustal subsidence associated with the mega earthquake during December 2004 Tsunami led to loss of 30% coral cover in north Andaman and 20% loss in south Andaman, respectively. Siltation and tourist activities in certain areas of south Andaman that were affecting the coral reefs were identified as important anthropogenic threats to the survival of the reefs. The study reviewed the recovery status of different coral species from existing literature and observed that massive species like the Porites sp. were comparatively stress tolerant, and showed good resilience to bleaching and with better recovery potential due to higher thermal thresholds. In contrast, species like the Fungiid sp. were reported to be susceptible to bleaching with capabilities to regenerate and recruit slowly.

An ecosystem model was constructed for the northern Bay of Bengal (nBoB) using Ecopath (version 6.4.4). The model covered an area of 18,500 km2. There were 32 functional groups in the model including the non-living group, detritus. Trophic levels (TLs) for individual groups ranged from 1.0 to 4.22. Ecotrophic efficiency for most of the small pelagic fishes was found to be greater than 0.7. For hilsa it was 0.853, indicating high exploitation of this fish within the system. The nBoB was estimated to be a low ascendancy area (~ 19.2%) with a system overhead of 80.8%, which indicates system stability and a certain maturity. The total system throughput and the total primary production/total respiration estimated for the study area indicate that nBoB is a maturing ecosystem. The mean TL of the catch for the study area was 3.115. The results indicate that the nBoB system is still in a developing stage. The low mean TL of the catch indicates fishing practices targeting fish of lower TLs in the system. In the long run, this may cause fishing down the food web, which will eventually lead to declining catches. These results indicate that present fishing practices are unsustainable for the nBoB ecosystem.

The hilsa, Tenualosa ilisha fishery in the northern Bay of Bengal (nBoB) is passing through a crisis manifested by the persistent decline of fish catch in spite of increasing efforts. During the period 2002–2015, the number of boats engaged in the fishery increased by 25% while the hilsa catch decreased by 13%. The exponential value (b) and condition factor (K) of hilsa has also decreased by 46% and 28% respectively. The value of fishing mortality (F = 2.34 year−1) has considerably exceeded the natural mortality (M = 0.56 year−1) during the study period. It is observed that in place of maximum exploitation rate (Emax) of 0.78, the current exploitation rate (E) of hilsa is 0.81 which is above the sustainable limit. It is a matter of serious concern that with 75% probability the first spawners of the population are being targeted by the present fishing practice. The present study observes that the hilsa population of nBoB are being significantly overexploited in the present level of fishing pressure. The maximum sustainable yield (MSY) limit for hilsa is estimated to be around 25,440 tons per year with the corresponding effort (fMSY) that may be deployed to achieve the above mentioned catch ranged from 3571 to 3987 (number of boats). It can be inferred that the hilsa fishery in the nBoB is being unsustainably exploited.

Graphical abstract, Over the last few decades several vegetation indices were used to map Mangrove forest using satellite images. Difficulty still persists in discrimination of mangroves from non-mangrove vegetation, especially in areas where mangrove species are mixed with other vegetation types. In the present study we have attempted to develop an improved index, which utilizes the information from the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) of Bhitarkanika mangrove forest of Odisha, India. These indices are negatively correlated (r = –0.988; p

The present paper dealt with the annual dynamics of the absorption coefficient of chromophoric dissolved organic matter at 440 nm {aCDOM(440)} during February 2015 to January 2016 in the continental shelf of northern Bay of Bengal (nBoB) for the first time. Sea surface salinity (SSS), chlorophyll-a (Chl-a), total suspended matter (TSM) were also analyzed. It was hypothesized that CDOM should exhibit significant spatial and temporal variability in this region. aCDOM(440) and spectral slope ranged between 0.1002 m−1–0.6631 m−1 and 0.0071 nm−1–0.0229 nm−1 respectively during the entire study period. Higher values of aCDOM(440) were observed in the near shore stations and gradually decreased towards the offshore. Significant seasonal variability of aCDOM(440) was observed between the monsoon and non-monsoon seasons (p

Hilsa (Tenualosa ilisha) is an important commercial fish in India. This study investigates relationships among Hilsa catch per unit effort (CPUE) and the corresponding lunar phase, rainfall variability, wind vector, and month in the northern Bay of Bengal. Hilsa catch during the monsoon season of three consecutive years (2013–2015) was analyzed by using a Generalized Least Square model with lunar phase and monsoon months (June–September) as categorical variables and wind direction as circular variable. Significantly higher Hilsa catch was observed during the waning crescent and waxing gibbous lunar phases and during easterly winds. There was no significant effect of wind velocity. Daily rainfall was significantly correlated with Hilsa migration toward the estuary. Among the four monsoon months, September exhibited the most positive significant correlation with the Hilsa CPUE. Model predicted CPUE underestimated the actual CPUE in 2016 by 20%

Absorption coefficient of chromophoric dissolved organic matter (CDOM) at 440 nm [ a CDOM (440)], sea surface salinity (SSS), total suspended matter (TSM) and chlorophyll- a (chl- a ) were measured during October, 2014 to March, 2015 in the shallow continental shelf waters of the Hugli Estuary, adjacent to West Bengal coast, India. The primary objective of the study was to characterize the relationship between a CDOM (440) and the above mentioned biogeochemical parameters. Upon analyzing the results, we observed that SSS portrayed the best possible relation with a CDOM (440) followed by TSM. Chl- a did not exhibit any statistically significant relationship with a CDOM (440). TSM showed a positive linear relationship with a CDOM (440) ( R 2 = 0.75) but the relationship did not work at all for the lower end members of TSM values. SSS and a CDOM (440) showed a strong negative relationship throughout the entire data range ( R 2 = 0.96). In the lower SSS ranges, the relationship showed maximum goodness of fit ( R 2 = 0.99). Though the goodness of fit between SSS and a CDOM (440) decreased for the higher SSS end members, the relationship was statistically significant all through.

Monthly catch of Hilsa in the Northern Bay of Bengal was modeled and predicted using the Bayesian structural time series (BSTS) with chlorophyll and rainfall as explanatory covariates. Chlorophyll and rainfall were used in the model with a lag time of eleven months and one month, respectively. These lag time values were determined from the exploratory data analysis. In this study, four separate models were developed to predict the Hilsa catch and compare the results. In the first model, the catch was predicted based on trend and seasonality of the previous years’ catch data. The second and third models predicted monthly catch with chlorophyll (having a lag time of 11 months) and rainfall (having a lag time of 1 month), respectively, as the only covariate in the model. The fourth model had both chlorophyll and rainfall as covariates with a lag time of 11 months and 1 month, respectively. The training mean absolute percentage error (MAPE) of the fourth model (measuring model fit) was observed as 0.2827, while the test MAPE (measuring model accuracy) was 0.2786. The coefficient values for both chlorophyll and rainfall were very close (0.999 and 1.064) which indicated the almost equal effect of both the parameters on the Hilsa catch. This study indicated that more abundance of the food material (phytoplankton) during the post-monsoon season would promote the growth and maturity of more Hilsa that would successively migrate towards river or estuary during the subsequent monsoon season and the catch would likely increase with the intensification of the southwest monsoon.

Partial pressure of CO

Potential fishing zones (PFZ’s) are those regions where the fishes aggregate due to an abundance of food and they are demarcated by tracing those regions in the ocean, where a sharp sea surface temperature (SST) gradient along with optimal chlorophyll (Chl) concentration co-exists at a given time. In this regard, Indian National Centre for Ocean Information Services (INCOIS) disseminates the daily PFZ forecasts in Bay of Bengal and Arabian Sea to aid the fishermen community. The present study is an endeavor to develop a local spatial model derived Potential Fishing Zone (PFZ) in the northern Bay of Bengal (nBoB) lying adjacent to the West Bengal coast. Satellite derived SST and chlorophyll data obtained for two consecutive winter seasons of 2010–11 and 2011–12 were used to generate line density (LD) raster. Shapefiles of INCOIS predicted PFZs were overlaid on these LD raster to extract the corresponding pixel values. Histogram ranges of the extracted pixels were fixed and same values lying in the LD raster of both SST and chlorophyll other than INCOIS PFZs were detected by a spatial model in ERDAS. The PFZs thus derived were validated against the ground fish catch data and it was observed that good fish catch was seen in the model derived additional PFZs also. The catch per unit effort (CPUE) values was found to be very close to that of the CPUE value of PFZ advisories of INCOIS. However, the CPUE in the non PFZ areas were significantly lower than the former two categories.

Conservation and management of Sundarban mangrove forest is difficult chiefly due to inaccessibility and hostile condition. Remote sensing serves as an important tool to provide up-to date baseline information which is the primary requirement for the conservation planning of mangroves. In this study, supervised classification by maximum likelihood classifier (MLC) has been used to classify LANDSAT TM and LANDSAT ETM satellite data. This algorithm is used for computing likelihood of unknown measurement vector belonging to unknown classes based on Bayesian equation. Image spectra for various mangrove species were also generated from hyperspectral image. During field visits, GPS locations of five dominant mangrove species with appreciable distribution were taken and image spectra were generated for the same points from hyperion image. The result of this classification shows that, in 1999 total mangrove forest accounted for 55.01 % of the study area which has been reduced to 50.63 % in the year 2010. Avicennia sp. is found as most dominating species followed by Excoecaria sp. and Phoenix sp. but the aerial distribution of Avicennia sp., Bruguiera sp. and Ceriops sp. has reduced. In this classification technique the overall accuracy and Kappa value for 1999 and 2010 are 80 % and 0.77, 85.71 % and 0.81 respectively.

Blackspotted Croaker ( Protonibea diacanthus ) is one of the most commer- cially important croakers which migrate along West Bengal coast during winter season. This paper deals with the importance of the species along with its market value and the cause of its popularity in West Bengal. This species is gaining prime importance among the fishermen due to the high market price of its swim bladder. The dried swim bladders are sold in local markets for Rs. 40,000-50,000 per kg. There is a risk factor involved as the fishermen do not get the catch at a time and, moreover, they often lose common pelagic fishes due to the usage of larger mesh nets. In spite of this risk, a shift from pelagic to demersal fishing across the northern Bay of Bengal marks an important emerging trend of winter fishing in this area.

Blackspotted Croaker (Protonibea diacanthus) is one of the most commercially important croakers which migrate along West Bengal coast during winter season. This paper deals with the importance of the species along with its market value and the cause of its popularity in West Bengal. This species is gaining prime importance among the fishermen due to the highmarket price of its swim bladder. The dried swim bladders are sold in local markets for Rs. 40,000-50,000 per kg. There is a risk factor involved as the fishermen do not get the catch at a time and, moreover, they often lose common pelagic fishes due to the usage of larger mesh nets. In spite of this risk, a shift from pelagic to demersal fishing across the northern Bay of Bengal marks an important emerging trend of winter fishing in this area., Protonibea diacanthus jedna je od gospodarski najvažnijih vrsta ribe na obali zapadnog Bengala u posljednjih nekoliko godina. Provedeno istraživanje u ovom radu bavi seispitivanjem tržišta i uzrocima popularnosti ove vrste u zapadnom Bengalu. Ova riba jako je važna za ribare zbog visoke tržišne cijene njezinog plivaćeg mjehura. Cijenaosušenih plivaćih mjehura na lokalnim tržnicama iznosi 40 000 – 50 000 indijskih rupija po kilogramu. Međutim, postoji velik rizik jer nemaju svi ribari dobar ulov u određenom vremenskom periodu i k tome često gube uobičajene pelagične ribe zbog uporabe prevelikih mreža.Unatoč riziku, postoji pomak od pelagičkog ka pridnenom ribolovu na sjeveru Bengalskog zaljeva, što pridonosi razvitku trenda zimskog ribolova u tim krajevima.