Using high-resolution, diurnally resolved observations, this study examines the physical and biogeochemical controls on the deep chlorophyll maximum (DCM) in the southwestern Bay of Bengal during the post–northeast monsoon transition (February 2024). Co-located hydrographic, optical, dissolved oxygen, and nutrient measurements were collected along an offshore latitudinal transect spanning Chennai, Puducherry, and Karaikal. A persistent DCM was observed between 55 and 80 m, aligned with the upper thermocline where light levels were reduced to ∼0.5–1% of surface photosynthetically available radiation. Chlorophyll-a concentrations within the DCM ranged from 0.6 to 1.2 mg m⁻³ and deepened northward in response to reduced haline stratification, deeper thermoclines, and improved optical clarity. Despite pronounced diurnal heating-cooling cycles at the surface, the DCM depth exhibited only minor fluctuations, indicating strong density-controlled confinement. Nutrient concentrations within the DCM ranged from 1.5 to 3 µmol L⁻¹ nitrate, 0.10–0.30 µmol L⁻¹ ammonium, and 2.5–5 µmol L⁻¹ silicate, while dissolved oxygen remained relatively uniform (3.4–4.0 mg L⁻¹). These results indicate that the Bay of Bengal DCM is closely associated with a stable density structure and exhibits variability consistent with photoacclimation and potential in situ nutrient recycling, rather than vertical displacement.

Accurate estimation of chlorophyll-a (Chl-a) is essential for monitoring phytoplankton biomass and marine ecosystem health. This study evaluates the performance of the Ocean Colour Monitor-3 (OCM-3) sensor in retrieving Chl-a concentrations in coastal and offshore waters of the southwest Bay of Bengal, using in-situ data collected between March—2023 and April—2024. Validation included regression analysis, Bland–Altman plots, and statistical error metrics. The performance of OCM-3’s OC4 algorithm was compared with global algorithms OC5 and OC6. In coastal waters, in-situ Chl-a ranged from 0.19 to 3.34 μg/l, while OCM-3 estimates ranged from 0.50 to 2.88 mg/m3. Offshore values ranged from 0.43 to 1.12 μg/l (in-situ) and 0.41–0.70 mg/m3 (OCM-3). OCM-3 showed good correlation with in-situ measurements (R2 = 0.62 coastal, 0.63 offshore), and lower RMSE (0.50 μg/l coastal, 0.18 mg/m3 offshore). OC5 and OC6 exhibited higher errors and under/overestimation trends, particularly in offshore waters. OCM-3 demonstrated reliable performance for Chl-a retrieval, but coastal uncertainties highlight the need for region-specific algorithm tuning. Continued validation with expanded in-situ datasets is recommended to enhance accuracy for ecological monitoring in the Bay of Bengal.

New and primary productivity measurements using δ15N and δ13C tracer technique were conducted in the Arabian Sea (AS) during the cruise from 17th December 2019 to 6th January 2020. New and primary productivity in the AS are mainly controlled by hydrodynamic and satellite-derived meteorological parameters such as wind speed, wind stress, sea surface temperature, aerosols concentration and Ekman pumping. Analysis of cruise samples from the 14 stations showed high surface productivity in the Ekman mass transport area followed by aerosol deposition region. New production measured 46.998 mmol N m2 d−1. Regenerated production was 37.060 mmol N m2 d−1 from ammonium and 39.220 mmol N m2 d−1 from urea. Primary production reached 89.595 mmol N L−1d−1. Rainfall events at some stations divulgated and not correlated with increased production, suggesting complex nutrient dynamics influenced by surface stratification and nutrient dilution. The f-ratio revealed lower nitrate uptake in open ocean regions compared to areas influenced by aerosol deposition and Ekman transport. This study characterized the intricate interplay of physical and biogeochemical processes affecting primary production in the AS.

The present study investigates the concentrations of 14 trace and heavy metals (Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Hg, As, and Se) in two oceanic tuna species (Thunnus albacares and Katsuwonus pelamis) collected from the Tharuvaikulam fish landing centre along the Tuticorin coast, Southeast India, to evaluate potential health risks associated with their consumption. The analysis focused on the muscle, liver, gill, and skin tissues which were investigated using ICP-MS to assess the potential health risks associated with their metal accumulation. The concentration patterns of trace metals in the organs of T. albacares were found to be Se > Al > Fe > Zn > Cr > Cu > Mn > Ni > Pb > As > Hg > Cd > Co in muscle, skin, gill, and liver. In K. pelamis, a similar pattern was observed in skin, gill, and liver in the order of Se > Al > Zn > Fe > Cr > Cu > Mn > Ni > Pb > As > Hg > Cd > Co. Selenium (Se) had the highest Estimated Daily Intake (EDI) value in both Thunnus albacares (0.325 mg/kg bw/day) and Katsuwonus pelamis (0.036 mg/kg bw/day), both of which exceeded the Provisional Tolerable Weekly Intake (PTWI) set by the Joint FAO/WHO Expert Committee on Food Additives. Target Hazard Quotient (THQ) values for all toxic metals in tuna from the Tharuvaikulam region were below 1 for both children and adults, indicating no significant health risks and aligning with previous findings on tuna fish species. Nevertheless, ongoing monitoring of trace metal levels in seafood from this region is recommended to ensure continued consumer safety.

The Gulf of Mannar, located on the southeast coast of India experienced a severe harmful algal bloom (HAB) caused by the dinoflagellate Noctiluca scintillans, in October 2021. This bloom had a devastating impact on marine fisheries and biodiversity affecting the regions from Pamban to Mundal. This study revealed significant temporal variations during the occurrence of the N. scintillans bloom. The average sea surface temperature (SST) ranged from 28 to 29 °C, while salinity varied between 38 and 36.5 psu. Chl-a levels ranged from 8.12 to 17.5 mg/m3. The cell density scintillans ranged from 3.27 × 106 to 2.83 × 103 cells/L across all stations. Post bloom observations revealed mass mortality of marine organisms including finfishes, shellfishes, sea anemones, sea hares, sea horses, and polychaetes. Fish mortality was significant, with a total estimated weight of 7.2 tonnes among these 0.96 tons of commercially important fish valued at US5.5 M. The bloom had a particularly detrimental effect on two damselfish species Dascyllus reticulatus and D. trimaculatus. The intense N. scintillans bloom killed 0.83 tons of damselfish, equivalent to 9 million fishes. The increasing frequency of HAB incidences in the region is likely attributed to environmental changes. Severity of the blooms highlights the urgent need for continuous monitoring and early-warning systems to mitigate future impacts on marine biodiversity. Developing effective management and conservation polices is essential for addressing these ecological threats.

The study assessed the seasonal and inter-annual variability of new production in the northern Indian Ocean (NIO) utilizing MODIS-Aqua satellite data during 2011–2020. The generated new production images are based on sea surface temperature (SST) and chlorophyll-a data, processed and analysed using the developed and validated empirical algorithm using in-situ datasets. The analysis focused on the Arabian Sea (AS) and Bay of Bengal (BoB), examining the seasonal changes. Data processing involved two approaches: first, using only SST, and second, incorporating chlorophyll-a data along with SST. The findings reveal higher new production uptake in the northern region during the winter, contrasting with the southern region, where uptake rates peak in the summer. Both AS and BoB generally exhibit lower productivity in the spring. The AS exhibits greater productivity than the BoB. This is mainly due to higher production in the summer (1.8 µmol N m−2d−1) and winter (1.7 µmol N m−2d−1), along with stronger downward fluxes associated with the deep mixed layer.

Accurate localization of unmanned aerial vehicle is crucial in global positioning system-denied environments. The existing localization-related approaches rely on the global positioning system signals, which are unreliable in certain conditions. The usage of inertial sensors in the localization methods is prone to sensor drift over time because that creates difficulties during accurate position estimation. To address these challenges, a novel acoustic localization method is proposed in this research article using extended Kalman filter. The array of acoustic sensors placed in the global positioning system-denied environment helps to detect time difference of arrival of signals for the acoustic localization. The proposed localization model is implemented for operating the unmanned aerial vehicle even in the limited global positioning system availability and reducing the effects of environmental noises and sensor drift. The advantages to integrate the extended Kalman filter model into time difference of arrival model are robust tracking capabilities and prediction ability of future position of unmanned aerial vehicle. For the experimental purpose, the real-time simulations are performed on the robot operating system, Gazebo and MATLAB environments. The robustness of the proposed method is evaluated based on the comparative analysis using the efficient performance measures of standard deviation and root-mean-square error. The proposed model provides significant potential for the applications of reliable unmanned aerial vehicle localization in the poor global positioning system coverage area and complex indoor environments. This research contributes more reliable and efficient localization with the potential implications for various applications such as disaster response, agriculture and security.

This article presents a study on design and testing of space sails using Al-polyurethane Shape memory polymer. The properties of the polymer are simulated and tested in the design phase, and the results are compared with the fabricated sail, which is considered nominal. The efficiency of the polyurethane sail is found to be approximately 86.5%. The controllability of the sail is enhanced using a heating system that uses light rays to heat the polymer at specific control spots. The relative deflection at these spots causes a deviation in solar momentum, resulting in a controlled displacement of the sail. This control system is found to be 42% more efficient than conventional vane-type deflection systems. The paper also presents the fabrication of a ground testing apparatus designed to test the sail specimen in laboratory conditions. The apparatus is capable of producing a vacuum chamber pressure up to −400 mm/Hg and includes a magnetic levitation platform with strong permanent magnets to neglect local gravitational effects. The platform provides support for fixing the solar sail frame made from carbon fiber composite material. The testing apparatus consists of a 1000-W halogen light source with intensity ranges of approximately 200,000 lux. Sail material with a reflective surface is exposed to controlled luminance under vacuum conditions to measure the deflection of the sail. Deflection values are recorded by means of a resistance type strain gauge and strain indicator arrangement. Plotting deflections with time period gives the acceleration of the sail inside the test apparatus. A coolant chamber with a ceramic base is also provided to reduce temperature effects inside the vacuum chamber. In conclusion, this study presents a promising approach for the design and testing of solar sails using shape memory polymer and a ground testing apparatus. The results of this research can contribute to the development of more efficient and versatile solar sail technology for fuel-free aerospace propulsion.

A study conducted from January to December 2018 examined seasonal variations in horizontal phytoplankton communities. A total of 93 species were identified, including 63 Coscinodiscophyceae, 4 Fragilariophyceae, 7 Bacillariophyceae, 15 Dinophyceae, and 4 Cyanophyceae. The highest species diversity and abundance occurred during the postmonsoon and premonsoon periods. Environmental parameters (viz., temperature, salinity, dissolved oxygen, pH, ammonia, nitrite, silicate, total suspended solids) were all statistically significant except for nitrite (p > .05). Multivariate statistical analyses (PCA and CCA) revealed that in the postmonsoon period, silicate and nitrate were responsible for the proliferation of phytoplankton abundance, species composition and density, while in the premonsoon period, temperature, salinity, and pH significantly influenced and favored specific phytoplankton groups (such as Chaetocerotaceae) in terms of species composition and abundance.

Nitrate uptake is an essential nutrient for primary production. A study focused on the surface waters of the Bay of Bengal (BoB), new, regenerated, and total production were estimated from nitrate, ammonia, and urea (nitrogen uptakes). Understanding nitrogen uptake rates in coastal waters, where nutrient limitations can disturb environmental biological productivity, is essential. A detailed study of these uptake rates and metabolic processes is required to develop effective mitigation strategies to prevent further degradation of these ecosystems. Total production ranged between 1.39 and 7.43 mmol N m2 d−1, new production ranged between 0.58 and 2.83 mmol N m2 d−1 and regenerated production ranged between 0.83 and 4.59 mmol N m2 d−1. The study observed a significant negative correlation nitrogen uptake along with pH, sea surface salinity (SSS), and sea surface temperature (SST) was observed in the study. The R2 values for SST were 0.605, 0.619, 0.503, 0.601, and 0.627; for SSS they were 0.688, 0.511, 0.498, 0.579, and 0.644 with nitrogen (Na15NO3), ammonium (15NH4Cl), urea (CO(15NH2)2), regenerated, and total production uptake, respectively. pH was highly correlated with nitrate uptake (R2 = 0.525), had a low correlation with ammonium uptake (R2 = 0.439) and a moderate correlated with urea uptake (R2 = 0.526). A positive relationship of nitrogen uptakes with chlorophyll-a, dissolved oxygen, and dissolved inorganic nitrogen (DIN) were observed. Chlorophyll-a had R2 value of 0.608, 0.126, 0.524, 0.526, 0.578, with Na15NO3, 15NH4Cl, CO(15NH2)2, regenerated and total production uptake respectively. Dissolved oxygen (DO) related to ammonium uptake showed a very poor correlation (R2 = 0.079) but a better correlation with urea (R2 = 0.534). New production uptake rate showed a high positive correlation with DO (R2 = 0.645), whereas regenerative production uptake rates showed a relatively low correlation (R2 = 0.519). The positive relationship between DIN and nitrogen uptake had corresponding R2 value of 0.642, 0.591, 0.558, 0.652 and 0.675 for nitrite, ammonium, urea, regenerated and total production uptakes respectively. Total nitrogen: Total phosphate (TN:TP) showed a positive correlation with ammonium. The TN:TP relationship fit nicely with R2 = 0.576 (nitrate uptake), 0.524 (ammonium uptake), and 0.503 (urea uptake) in the coastal BoB. Hence, by applying statistical analysis, principal component analysis and pearson correlation, the interdependency of the environmental parameters enhancing the new production has been confirmed.

The study investigated the new and regenerated production using 15N tracers in the western Bay of Bengal, with observations were made in a vertical water column and sunlight gradients under stratified oligotrophic conditions, which are the major changes that distinguish the hydrobiological parameters associated with the deep chlorophyll maximum (DCM). In this study, new and regenerated production were measured in at different zones such as the surface, the DCM region and the euphotic depth (below 1% of light intensity) during the high stratification period. The results showed that new and regenerated productivity at the surface was low, while higher light intensity decreased productivity at the surface and productivity in the DCM layer increased significantly. Productivity at different location within regions is primarily controlled by the supply of nitrogen nutrients from deep within the region. In contrast, productivity at a given location with the available nutrient pool, at different depths is highly influenced by light availability. The study region exhibited potential for moderate export production during spring inter-monsoon, as is the case in other parts of the Indian Ocean. The f-ratio was estimated to be 0.2, which is a very low value in deep water and plays an important role in the Earth’s carbon cycle, as carbon transported to the deep ocean is absorbed from the atmosphere, and the ocean thus acts as a carbon reservoir. The results also found that the availability of nitrogen nutrients is capable of exporting a significant part of the total production to the deep ocean when conditions are favorable. Our results suggest that the Bay of Bengal may be equally important in its efficiency to export productivity to the deep sea and the DCM layer. Statistical analysis revealed a positive correlation between nitrogen productivity and chlorophyll-a, dissolved inorganic nitrogen and total nitrogen: phosphorous ratio.

Silicate is a significant prerequisite for the growth and development of primary producers, mainly in diatoms, it remains a prevalent contributor. Satellite ocean colour sensors data are broadly utilized for the identification, mapping and monitoring the phytoplankton characteristics, spatial and temporal. In this study, an empirical algorithm was developed for mapping the silicate concentration an important nutrient for planktonic diatoms depending on the relationship between chlorophyll- a , Sea Surface Temperature (SST) and silicate at a high spatio-temporal resolution. Three dimensional polynomial functions, such as plane, paraboloid, Gaussian and Lorentzian functions were used to correlate SST, chlorophyll- a and silicate. Among these the paraboloid function provided significant relationship between the variables with an R 2 value of 0.828. Validation of Visible Infrared Imaging Radiometer Suite (VIIRS) derived SST ( R 2 = 0.634, Mean Normalized Bias (MNB) = 0.006, Root Mean Square Error (RMSE) = 0.280 and Standard Error of Estimation (SEE) = +/- 0.227) and chlorophyll- a ( R 2 = 0.523, MNB = 0.369, RMSE = 0.846, and SEE = +/- 0.632) observed better synchronization with in situ measurements of SST and chlorophyll- a , respectively. The VIIRS-derived silicate algorithm provided better agreements with in situ silicate concentration ( R 2 = 0.784, MNB = -0.001, RMSE = 1.394 and SEE = +/- 0.839) along the Southwest Bay of Bengal.

Despite their widespread use and versatility, plastics pose a threat to the environment due to emerging contaminants in coastal and marine ecosystems. The present investigation focused on anthropogenic activities like tourism, fishing, and recreation while surveying plastic waste along the Cuddalore the coast. The survey was carried out during the summer season of 2021 (the lockdown) and the post monsoon season (post lockdown) of 2022. During the summer lockdown, station S1 had the highest abundance of plastic with 18.8 & PLUSMN; 5 items/m2, followed by S3 (4.7 & PLUSMN; 1.2 items/m2), S2 (4.3 & PLUSMN; 1.0 items/m2), and S4 (3.6 & PLUSMN; 1.2 items/m2). Nevertheless, after the lockdown, the highest abundance of plastic was observed at station S1 (25.6 & PLUSMN; 3.5 items/m2), followed by S3 (20.9 & PLUSMN; 9.7 items/m2), S2 (17.5 & PLUSMN; 8.5 items/m2), and S4 (14.6 & PLUSMN; 4.9 items/m2). The abundance of plastic items on the study beaches significantly increased (p<0.05) during the post lockdown period. White, translucent, green, yellow, and blue plastic was found in abundance on all four study beaches. To assess the health status, the Clean Coast Index (CCIi), which shows silver beaches (57.08%), Samyarpettai (43.34%), Periyakuppam (34.88%), and Puthukuppm (31.2%), all of which are highly polluted. The abundance of marine plastic trash along the Cuddalore the coast has been significantly affected by extensive fishing, recreation, tourist, and rituals. To better understand marine plastic pollution and the need for better waste management throughout the Indian coast, this study builds a baseline for beach littering and provides an explanatory framework for further study.

This study presents a synthesis of surface water partial pressure of CO2 (pCO2) and nutrient measurement in the southwest Bay of Bengal (swBoB) from 2014 to 2020 and characterizes the spatial and temporal variability. pCO2 rates found to be high (1191μatm) during the 2015 monsoon and low (176 μatm) in the summer season during the month of May 2015. The inter-annual CO2 fluxes varied from −4.79 to 9.97 mmol Cm−2d−1. The significant a negative CO2 flux (−4.79 mmol Cm−2d−1) was recorded during the summer season in the year 2019, whereas a positive significant CO2 flux (9.97 mmol Cm−2d−1) was observed during the monsoon in 2014. Major physical parameters are at their highest during summer owing to increased high solar radiation during cloud-free circumstances, reduced or inadequate riverine flux, and a lack of vertical mixing of the water column, which results in the lowest nutrients concentration, Dissolved Oxygen (DO), Dissolved Inorganic Nitrogen (DIN), Dissolved Organic Carbon (DOC), chlorophyll-a, Particulate Organic Carbon (POC), pCO2, that leads to negative CO2 flux to the atmosphere. In contrast during monsoon season colossal discharge of freshwater high DO, DIN, DOC, chlorophyll-a, POC, pCO2 as results source CO2 flux to the atmosphere. Statistical analysis the correlation coefficient depicts Total Alkalinity (TA), DIC, POC, DIN, and DO found a positive correlation with pCO2 and fCO2 during the monsoon season. In the swBoB, pCO2 had a negative relationship with sea surface temperature (SST), sea surface salinity (SSS), and pH because CO2 solubility changes with SST and increases in cold water rather than warm water. In this study, we examine the association between all carbonate variables and the SSS and SST to better understand seasonal fluctuations.

Abstract The abundance, diversity, taxonomic composition and functional structure of benthic ciliate assemblages were studied in the intertidal zone of two estuaries with contrasting conditions. The Chernaya (CH) is a small (2-km long) sub-Arctic estuary in the White Sea; the Vellar (VE) is a large (20-km long) tropical estuary in the Bay of Bengal. At both sites, the average abundance and biomass of ciliates were similar and quite typical of other marine interstitial habitats. The diversity was high (114 species in CH; 39 taxa, mainly identified to the genus or putative species level, in VE). Spatial distribution patterns in abundance, biomass and taxonomy-based diversity indices differed between the estuaries. In contrast, most functional traits followed similar trends in both estuaries. In particular, from the riverine part seaward, the ratio of raptorial algivorous ciliates to bacterio- and detritovore fine filter feeders increased, as well as the ratio of crawling or gliding ciliates to free-swimmers. Mean body size and oblongness also increased seaward. No clearly defined diversity minima were found in the mid-estuary oligohaline zones. The results are discussed in the context of some general concepts in estuarine ecology.

Hardware in loop simulation HILS-based waypoint simulation for fixed wing unmanned aerial vehicles is proposed in this paper. It uses an open-source arducopter as a flight controller, mission planner, and X-plane simulator. Waypoint simulation is carried out in the flight controller and executed in an X-plane simulator through a mission planner. A fixed wing unmanned aerial vehicle with an inverted T tail configuration has been chosen to study and validate waypoint flight control algorithms. The data transmission between mission planner and flight controller is done by serial protocol, whereas data exchange between X-plane and mission planner is done by User Datagram Protocol (UDP). APM mission planner is used as a machine interface to exchange data between the flight controller and the user. User inputs and flight gain parameters, both inner loop and outer loop, can be modified with the help of a mission planner. In addition to that, the mission planner provides a visual output representation of flight data and navigation algorithm.

Understanding the relationship between atmospheric and oceanic carbon cycles necessitates measuring geographical and temporal variations of surface water partial pressure of carbon dioxide (pCO2). The seasonal pCO2 maps have been developed using MODIS-derived SST and chlorophyll for four different seasons to calculate air–sea flux of CO2 at basin scale. Summer in 2017 had the lowest pCO2 value (263 µatm), whereas monsoon season in 2016 had the highest (553 µatm). From 2010 to 2019, atmospheric pCO2 level fluctuated from 371 to 396 µatm with progressive growth of atmospheric pCO2 at 2.5 μatm year−1. The inter-annual CO2 flux ranged between − 3.58 and 3.64 mmol C m−2 day−1. Significant negative CO2 flux (− 3.58 mmol C m−2 day−1) was observed in 2015 premonsoon, indicating that the Bay of Bengal was a net sink for atmospheric CO2, while served as a net source of CO2 to the atmosphere in 2013 monsoon season with a significant positive flux of CO2 (3.64 mmol C m−2 day−1) to the atmosphere. The annual CO2 sink was active in 2015 (− 1.17 mmol C m−2 day−1) which showed increased trend from 2014 to 2018 with a range of − 1.17 to − 0.26 mmol C m−2 day−1. The Bay of Bengal was found to be a substantial CO2 contributor to the atmosphere in 2013 (3.64 mmol C m−2 day−1) and 2012 (3.27 mmol C m−2 day−1). In this context, the southwest Bay of Bengal serves as a net sink of atmospheric pCO2 during summer season on an annual scale, and a weak sink during postmonsoon and premonsoon seasons, while served as a strong source of CO2 to the atmosphere during monsoon season from 2010 to 2019 with super saturation of CO2.

The seasonal and inter-annual variability of Total Alkalinity (TA) concentration was studied in the Bay of Bengal from 2003 to 2019 by using MODIS-Aqua derived sea surface temperature (SST) and sea surface salinity (SSS) products. The satellite derived TA showed a positive relationship with in-situ TA with (R2 = 0.67, RMSE = ±27.53 μMol/kg, SEE = ±32.16 and uncertainty error = 2287μMol/kg). The seasonal SST, SSS and TA portray the clear seasonal pattern between the seasons without any rapid change increase or decrease in trend observed over the years. In contrast to other seasons, the spring inter-monsoon was observed to have a warm surface water temperature with high salinity and TA. Strong wind and excessive cloud cover during the summer monsoon result in the reduction of ocean surface heat, which favours sea surface cooling and shallow mixed layer depth, resulting in low SST, SSS, and TA compared to the spring inter-monsoon. During fall inter-monsoon, the reversal of East India coastal current directs warm water from north to south and the weak wind that prevails in this region enhances stratification. During winter, low-saline water compensates the static stability loss by thermal inversion from the sea surface resulting in surface cooling with coldest SST, low SSS and TA during this period.

Abstract Marine fisheries and biodiversity in the Gulf of Mannar, Tamil Nadu, were severely impacted by the blooms of dinoflagellate Noctiluca scintillans, on 10th October 2021. The bloom affected the marine biodiversity in a 15 km2 area between Keelarai to Mudal in the Gulf of Mannar, Tamil Nadu, India. Post bloom observations showed mass mortality of a variety of finfish, ornamental fish, bivalves, shellfish, sea anemones, sea slugs, sea cucumbers, sea horses, polychaete worms, and seaweed that washed ashore. Two damselfish species Dascyllus reticulatus and D. trimaculatus were deleteriously affected. The intense N. scintillans bloom killed 0.83 tons of damselfish, equivalent to approximately 9 million fish, and 1.67 tons of commercially important fish valued at US$ 11.5 M.