http://nopr.niscpr.res.in/handle/123456789/60173 Fri, 09 Oct 2026 04:37:22 GMT 2026-10-09T04:37:22Z https://http://nopr.niscpr.res.in:443/retrieve/185211/IJMS cover.png http://nopr.niscpr.res.in/handle/123456789/60173 http://nopr.niscpr.res.in/handle/123456789/60195 Title: Response of surface chlorophyll to aerosol dust input in the Central Arabian Sea Authors: Roy, R; Prakash, S; Lotliker, A; Sudhakaran, P S; Choudhury, S B Abstract: The decadal trends in satellite-derived surface chlorophyll in conjunction with Aerosol Optical Depth (AOD) are explored in a unique area in the central Arabian Sea, known to mimic High Nutrient and Low Chlorophyll (HNLC) like conditions during late summer monsoon. The analysis indicates two recurring seasonal blooms, possibly associated with distinct biogeochemical processes in the studied region. Furthermore, the mineral dust deposition in July every year coincides with one such increase in surface chlorophyll followed by a lag period until winter monsoon. This rapid increase in the phytoplankton biomass just after the aeolian input is possibly due to an enhancement in soluble iron within the mixed layer, as suggested by AOD dust data. Most likely, this rapid increase in biomass may induce further depletion of soluble iron leading to HNLC-like conditions during the late Summer Monsoon, as reported earlier. This hypothesis is consistent with the satellite observation, which shows a decrease in surface chlorophyll during subsequent months until the convective mixing between December – January (winter monsoon). The study reveals that the presence of the HNLC region in the central Arabian Sea during the summer monsoon is not perennial like the Southern Ocean. Instead, it is a transient phenomenon primarily controlled by aerosol deposition and rapid uptake of soluble iron, which facilitate the diatom blooms as suggested by the recent output from the NASA Ocean Biogeochemical Model (NOBM). Page(s): 297-303 Fri, 01 Apr 2022 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/60195 2022-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/60194 Title: Identification of CaCO3 polymorphs of shellfish by FTIR spectroscopy and evaluation of metals adsorption by powdered exoskeleton shell Authors: Singh, K S; Sawant, S G Abstract: Shellfish are found in the coastal region throughout the tropical, sub-tropic and temperate zone. A variety of shellfish species are known in nature. Being filter-feeding organisms, organic and inorganic substances easily gain entry into them. Very often, heavy metals such as Cd, Pb, Cu, and even Hg can accumulate in their bodies. The presence of these heavy metals in shellfish is an indicator of environmental pollution, and a threat to humanity as these fish are widely consumed in coastal regions. Here, biochemical analysis of exoskeleton shell mainly composed of polysaccharides, proteins and calcium carbonate (CaCO3) - have been studied. Calcium carbonate (CaCO3) which is one of the major constituent of the exoskeleton part of the shellfish exists in three polymorphs viz., calcite, aragonite and vaterite. The identification of CaCO3 polymorphs in shellfish is extremely important as it gives information on the structural arrangement of the calcium carbonate lattice in these organisms. Here, we present a convenient method for the identification of CaCO3 polymorphs in shellfish collected from Goa, west coast of India, with Fourier-Transform Infrared Spectroscopy (FTIR) and further confirmed by powder X-ray analysis. Additionally, the potential of the powdered shell biomass for metal removal from an aqueous medium has also been investigated. Page(s): 304-309 Fri, 01 Apr 2022 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/60194 2022-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/60192 Title: Evaluation and performance of satellite-derived bathymetry algorithms in turbid coastal water: a case study of Vengurla rocks Authors: Ashphaq, M; Srivastava, P K; Mitra, D Abstract: The coastal region bathymetry is increasingly becoming necessary for emerging needs of navigation and development along coasts. Satellite-Derived Bathymetry (SDB) has been examined as a viable alternative for hydrographic surveys for the past few decades to reduce the data acquisition efforts in coastal regions and augmentation of periodic updating of Electronic Navigational Charts (ENCs). The previous studies have applied SDB algorithms in less complex waters due to the limitations of SDB algorithms in turbid and varying shallow waters. This paper analyses three different mediumresolution satellite imagery data to derive bathymetry in a navigably very complex and highly turbid region, Vengurla rocks, situated on the west coast of India. The objective of the study was to evaluate the best suitable technique for SDB in turbid water. The bathymetry product images have been derived using the two most commonly utilized log ratio, and linear ratio transformation; three semi-automated methods, Principal Component Analysis (PCA), Independent Component Analysis (ICA), and ratio transform; and Machine Learning (ML) regression algorithms. Among the applied transform and algorithms, the ML algorithm using 561 nm band data performed the best, resulting in R2 of 0.77, RMSE of 3.4 m, and MAE of 2.8 m. This work established that open source images of sensor OLI/Landsat-8 satellite provide the best results of SDB estimation in complex turbid water by applying ML algorithms. However, extreme turbid and complex regions resulted in more erroneous SDB estimation specifying the need for refining algorithms using bio-optical parameters. Page(s): 310-321 Fri, 01 Apr 2022 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/60192 2022-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/60190 Title: Hatchery production of juveniles of pharaoh cuttlefish, Sepia pharaonis (Ehrenberg, 1831) from stranded eggs and sea ranching along the Thoothukudi coast Authors: Kavitha, M; Jagadis, I; Prabu, D Linga; Kalidas, C; Ranjith, L; Willington, S Abstract: Accidentally entangled and stranded egg masses of Sepia pharaonis in fishing gears were collected from various landing centres of Thoothukudi district. The stranded egg masses were incubated, hatched and larval rearing was carried out at the Molluscan Fish Hatchery of Tuticorin Research Centre of CMFRI. The average hatching rate of S. pharaonis was 95 % for the eggs collected from the fishing nets. The size of day 1 paralarvae of S. pharaonis was 5.46±0.06 mm and reached the average size of 40.10±1.15 mm length and 9.6±0.20 g weight on day 60 with the average survival rate of 70 %. Maximum weight gain (%) was noticed between 20 – 40 days. The paralarvae of S. pharaonis fed with suitable live feeds until 50 days, after which fed with dead fish and shrimp. The juveniles were transformed as broodstock with an average length of 137.4±8.08 mm and weight of 229.7±21.54 g on 180th day of culture. In the hatchery, the first captive spawning was witnessed on 167th day and the eggs laid by the females ranged from 46 – 118. However, the captive bred egg masses failed to hatch out. Therefore, the hatchery technology needs to be perfected through the development of nutritionally improved broodstock diet to ensure better hatching. During the years 2016 – 2018, altogether 8400 numbers of hatchery reared 60 days old juveniles of S. pharaonis were ranched into the fishing grounds off Tuticorin coast. The biological significance of sea ranching activities to replenish the natural stocks requires further research and evaluation. Page(s): 322-326 Fri, 01 Apr 2022 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/60190 2022-04-01T00:00:00Z