http://nopr.niscpr.res.in/handle/123456789/62293 2026-10-13T00:39:31Z 2026-10-13T00:39:31Z Yadhunath, E M Seelam, J K Pednekar, P S Rajive, R K Gowthaman, R http://nopr.niscpr.res.in/handle/123456789/62300 2023-07-11T06:39:18Z 2023-07-01T00:00:00Z

Title: Longshore currents on a meso-tidal beach of Goa, India - Measurements and improved formulae Authors: Yadhunath, E M; Seelam, J K; Pednekar, P S; Rajive, R K; Gowthaman, R Abstract: Field experiments in the surfzone were conducted on a meso-tidal beach stretch between Sinquerim and Baga off Goa on India's central west coast. Surfzone waves and currents were measured using an array of seabird wave and tide gauges and Aanderaa RCM9 current meters. Rip currents were observed prominently in this stretch with increased intensity during the ebb tide. Six longshore current prediction equations are tested for their suitability in this region. The Longshore Current (LSC) estimated using these equations showed a wide range of Mean Absolute Percentage Error (MAPE) and Scatter Index, and the correlation coefficients were also found to be less than 50 %. Hence, these equations are further modified by including the alongshore wind shear component, and the LSC was re-estimated to study the variations in current along the Candolim beach. It was observed that the correlation coefficients improved up to 64 % for most of the equations. Page(s): 867-877

2023-07-01T00:00:00Z Panicker, D V Vachharajani, B Srivastava, R Oza, S R http://nopr.niscpr.res.in/handle/123456789/62299 2023-07-11T06:34:46Z 2023-07-01T00:00:00Z

Title: New insight in the determination of thermodynamic equilibrium thickness using heat budget over Barents Sea Authors: Panicker, D V; Vachharajani, B; Srivastava, R; Oza, S R Abstract: This paper examines various atmospheric and sea ice data to understand the Barents Sea's small-scale energy balance. The ERA-5 reanalysis products are used to calculate the atmospheric budget. Seasonal cycles detected using oceanatmosphere interactions show that potential energy is substantially higher than kinetic energy over the Barents Sea, which is one of the reasons for it being colder than other places. The month of June experiences maximum radiation at the top of the atmosphere with a value of 16.19 Wm-2 and December experiences minimum with a value of 0.11 Wm-2. However, the heat flow at the surface is the highest during December with values ranging between 0.64 Wm-2 and 0.69 Wm-2. The system is constrained by declining solar flux, increasing heat flux at the Earth's surface, and atmospheric transport. Sea ice minimum and maximum months in the Barents Sea exactly coincide with those of the Arctic Sea. However, Barents Sea ice thickness is only limited to 3.5 m, but for the Arctic it is seen extending up to 4.5 m. Additionally, the area has recently experienced a massive exchange of heat (energy) between the ocean and the atmosphere, which is believed to be due to Atlantification, which is a well-known process. The Barents Sea is the region where the process of Atlantification is first observed. A new method has been developed to estimate the Thermodynamic Equilibrium Thickness (TET) of the sea. TET is calculated using a thresholding technique that is applied to total thermal radiation. The approach adopted for TET extraction is important as it generates several important fluxes, including the energy flux between the ocean surface and the atmosphere above it. Page(s): 878-890

2023-07-01T00:00:00Z Pathak, V Bhutia, R N Chennuri, S Kumar, R Bhushan, S Deshmukhe, G Jaiswar, A K http://nopr.niscpr.res.in/handle/123456789/62298 2023-07-11T06:31:56Z 2023-07-01T00:00:00Z

Title: Dharamtar estuary: Unexplored ichthyofaunal diversity, a thrust area for diversity conservation Authors: Pathak, V; Bhutia, R N; Chennuri, S; Kumar, R; Bhushan, S; Deshmukhe, G; Jaiswar, A K Abstract: The Dharamtar estuary has been receiving ecologists’ attention, as the ecosystem is highly-stressed due to anthropogenic activities. This mangrove-associated critical ecosystem plays a vital role in the ichthyofaunal assemblages. Thus, the objective of the present study was to describe the ichthyofaunal diversity and their assemblages. The samples of the fishes were collected from Dol net landings from the Dharamtar estuary, part of the Arabian Sea. During the investigation, a total of 91 fish species belonging to 37 families and 12 orders were recorded. The exotic species Clarias gariepinus was recorded for the first time from the estuary. The fishes of the Dharamtar estuary were categorized as Not Evaluated (32 %), Data Deficient (5 %), Least Concerned (56 %), Near Threatened (3 %), Vulnerable (3 %) and Endangered (1 %) as per the IUCN criteria; where, 7 % of the species were traumatogenic, 5 % poisonous, 2 % venomous, and 1 % were with potential pest characteristics. The rich diversity of the estuary is associated with the sheltered area provided by mangroves that facilitates the assemblages, growth and survival of larval and juvenile fish. The results of the present investigation will be helpful in stock differentiation, biological study, conservation, etc. Page(s): 891-899

2023-07-01T00:00:00Z Rajesh, K M Rohit, P Ghosh, S Muthurathinam, M Sivadas, M Anulekshmi, C Azeez, P A Manas, H M Vinothkumar, R Nakhawa, A D Abdussamad, E M http://nopr.niscpr.res.in/handle/123456789/62297 2023-07-11T06:27:51Z 2023-07-01T00:00:00Z

Title: Diet composition and feeding behavior of largehead hairtail Trichiurus lepturus Linnaeus 1758 along the Eastern Arabian Sea and Western Bay of Bengal Authors: Rajesh, K M; Rohit, P; Ghosh, S; Muthurathinam, M; Sivadas, M; Anulekshmi, C; Azeez, P A; Manas, H M; Vinothkumar, R; Nakhawa, A D; Abdussamad, E M Abstract: Information on diet composition and feeding habits of species is very much essential for the scientific planning to develop sustainable management plans. The feeding biology of Trichiurus lepturus was studied during 2014 to 2018 from 6167 and 3346 specimens collected on a weekly basis along Eastern Arabian Sea (EAS) and Western Bay of Bengal (WBB), respectively. Crustaceans mainly represented Acetes spp. (98.6 %) and were categorized as dominant and preferred (%QI = 51.35; %IRI = 53.31) food item; teleosts were categorized as dominant and secondary (%QI = 47.46; %IRI = 45.71) food items and molluscs as accidental and accessory food items of T. lepturrus based on the values of dietary coefficient and Index of Relative Importance along the Eastern Arabian Sea (EAS) while, teleosts were completely dominant (%QI = 99.61; %IRI = 99.27) with both molluscs (%QI = 0.34; %IRI = 0.56) and crustaceans (%QI = 0.01; %IRI = 0.17) forming accessory and accidental food items along the Western Bay of Bengal (WBB). The teleostean prey items belonging to 23 genera were encountered in the guts of T. lepturus from EAS with Stolephorus spp. (17.09 %), Sardinella longiceps (6.65 %), Decapterus spp. (5.75 %), Rastrelliger kanagurta (1.36 %), and Megalaspis cordyla (0.89 %) as major component; whereas, in WBB, 16 genera of teleosts representing Sardinella longiceps (50 %), Stolephorus spp. (31.52 %), Decapterus spp. (4.57 %), and Rastrelliger kanagurta (2.26 %) formed the major portion of diet by %IRI. Crustaceans were dominated by Acetes spp. (52.61% IRI) in EAS, while other crustaceans’ contribution as prey item was negligible. However, along WBB, the crustaceans’ contribution as food components was very minimal. Molluscs did not contribute much as dietary constituents of T. lepturus in both EAS and WBB. About 50.15 % and 56.83 % of the stomachs had food content in various proportions in EAS and WBB, respectively and rest of the stomachs were empty. Page(s): 900-908

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