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In recent years, shoreline determination has become an issue of increasing importance and concern, especially at the local level, as sea level continues to rise. This study identifies the rates of absolute and net erosion, accretion, and shoreline stabilization along the coast of Kuakata, a vulnerable coastal region in south-central Bangladesh. Shoreline change was detected by applying remote sensing and geographic information system (RS-GIS)-based techniques by using Landsat Thematic Mapper (TM), Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) satellite images at 30-m resolution from 1989, 2003, 2010, and 2020. The band combination (BC) method was used to extract the shoreline (i.e., land-water boundary) due to its improved accuracy over other methods for matching with the existing shoreline position. This study also used participatory rural appraisal (PRA) tools which revealed the societal impacts caused by the shoreline changes. Coupling RS-GIS and PRA techniques provides an enhanced understanding of shoreline change and its impacts because PRA enriches the RS-GIS outcomes by contextualizing the findings. Results show that from 1989 to 2020, a total of 13.59 km2 of coastal land was eroded, and 3.27 km2 of land was accreted, suggesting that land is retreating at about 0.32 km2 yr-1. Results from the PRA tools support this finding and demonstrate that fisheries and tourism are affected by the shoreline change. These results are important in Kuakata, a major tourist spot in Bangladesh, because of the impacts on fisheries, recreation, resource extraction, land use planning, and coastal risk management.

In coastal India, water extraction for commercial salt pans is changing the habitat of the little stint.

The ingestion of plastic debris has been studied in many marine fish species, although comparisons between species can be difficult due to factors thought to influence ingestion rates, such as habitat preference, feeding behaviours and trophic level. Sardines are found internationally in many coastal environments and represent a potential sentinel species for monitoring and comparing marine plastic exposure rates. We conducted a pilot study, examining the rate of plastic ingestion in 27 commercially caught sardines (Sardinops sagax) from a low populated coastal region of Western Australia. A total of 251 potentially anthropogenic particles were extracted by chemical digestion of the gastrointestinal tract and classified visually. Fibres were the dominant type of material recovered (82.9%), with both yellow (39.8%) and black (32.7%) coloured particles commonly observed. A subset of 64 particles (25.5%), were subject to Fourier transform infrared (FTIR) spectroscopy to identify polymer composition. This chemical characterisation identified seven plastic items (polypropylene, nylon and polyethylene) and a variety of cellulose-based material that was further examined and classified as natural or semi-synthetic. The mean plastic ingestion rate was 0.3 ± 0.4 particles per fish, suggesting Western Australian sardines ingest relatively low concentrations of plastic when compared to international sardine populations examined using similar methodologies. Despite comparatively low concentrations, plastic and semi-synthetic material are still being ingested by sardines from a low populated coastal region demonstrating the ubiquitous nature of the marine debris problem.

In recent years, attaining gonadal maturation in smaller Hilsa (Tenualosa ilisha) has become a burning issue for Hilsa fishery of Bangladesh. Causes of early maturation are not yet clearly understood. Along with environmental parameters, genetic differentiation within the population was hypothesized as the main driver, and therefore, assessing the correlation between gonadosomatic index (GSI) and environmental factors and analyzing genetic diversity were set as objectives of the present study. To address these complex issues, six diverse habitats across Bangladesh were chosen for Hilsa sample collection. For GSI, gonad was dissected from fresh fish and preserved in Bouin's fluid for histological observation. Water quality parameters such as temperature, dissolved oxygen, pH, and salinity were also assessed. 35 fish from each habitat were used to extract and amplify DNA through the PCR technique, and genetic diversity was examined. Further, to draw a firm conclusion, the phylogenetic tree of the Hilsa population was developed by the unweighted pair-group method of arithmetic mean method based on the Cyt b gene of mitochondrial DNA. Results of GSI studies revealed that peak spawning months of T. ilisha were in October and February, where October showed the highest values in all six habitats. Histological examination showed different stages of gonadal development in different sizes and ages of Hilsa. Among all sampling sites, no statistical difference was observed for GSI value; however, smaller sized and aged Hilsa being ripped were evident in Gaglajur Haor and Kali River. Among the observed water quality parameters, temperature correlated with GSI strongly. Increased GSI was observed with temperature augmentation from downstream to upper stream, irrespective of body size and age. A perplex correlation between dissolved oxygen of observed habitats and GSI was executed. Other physico-chemical parameters viz. pH and salinity exhibited weak and moderate positive associ

The seasonality of eddy kinetic energy (EKE) is analyzed in the north Indian Ocean by adopting high-resolution ocean reanalysis data. Significant eddy energy can be mainly spotted in six regions, including the Somali Current (SC) region, the Gulf of Aden, the Laccadive Sea, the east of Sri Lanka, the East Indian Coastal Current (EICC) region, and the northwest of Sumatra. As the most energetic region, the EKE averaged above 200 m could exceed 0.15 m2·s-2 in the SC region, whereas the mean EKE above 200 m is less than 0.04 m2·s-2 in the other regions. The barotropic and baroclinic instabilities are vital to eddy energy, and the contribution of each term in the barotropic/baroclinic equations varies with season and region. In the SC region and EICC region, EKE is primarily generated by barotropic conversion due to the sharp velocity shear caused by the strong SC during the summer monsoon and the EICC from March to June. For the other regions, the leading source of EKE is the eddy potential energy (EPE), which is extracted from available potential energy of mean flow via baroclinic conversion, and then the EPE is converted into EKE through vertical density flux. Once generated, EKE will be redistributed by pressure work and advection via eddy energy flux, which varies in sync with the monthly variation of total EKE, transporting EKE to the adjacent region or deeper layer. From the vertical aspect, eddy energy conversions are more prominent above 200 m. The maximal EKE and barotropic conversion mostly occur at the surface, whereas the EPE and baroclinic conversion may have two peaks, which lie at the surface and in the thermocline. Using the satellite altimeter data and wind data, we further investigate the impact of geostrophic eddy wind work, which reveals a slightly dampening effect to EKE in the north Indian Ocean.

Recent studies suggest that pelagic sediments can enrich rare-earth elements (REE) acting as a significant reservoir for the global REE budget as well as a potential resource for future exploitation. Although Ca-phosphate (e.g., bioapatite fossils) and Fe-Mn (oxyhydr)oxides (e.g., micronodule) have been considered important REE carriers in deep-sea sediments, the proportion of REE held by each mineral phase remains enigmatic. Here, we have investigated the sediments from two promising REE-rich prospective areas: the Tiki Basin in the Southeast Pacific (TKB) and the Central Indian Ocean Basin (CIOB). The mineral grains including bioapatite fossils and Fe-Mn micronodules have been inspected individually by in-situ microscale analytical methods. Correspondently, the REE bound to Ca-phosphate and Fe-Mn (oxyhydr)oxides have been sequentially extracted and quantified. The crucial role of Ca-phosphate is substantiated by sequential leaching which reveals its dominance in hosting ~69.3-89.4% of total REE. The Fe-Mn (oxyhydr)oxides carry ~8.2% to 22.0% of REE in bulk sediments, but they account for ~70.0-80.5% of Ce owing to their preferential adsorption of Ce over the other REE. Surface sediment on modern seafloor can accumulate high REE contents resulting from the REE scavenging by the host phases within the range of sediment-seawater interface. Differences between TKB and CIOB samples indicate that the REE enrichment in the deep-sea environment may be controlled by multiple factors including the productivity of overlying seawater (e.g., phosphorus flux), water depth relative to carbonate compensation depth (CCD), sedimentation rate, redox condition, and hydrothermal vent input (e.g., Fe-Mn precipitations).

No-take marine reserves are often located in remote locations far away from human activity, limiting perceived impact on extractive users but also reducing their use for investigating impacts of fishing. This study aimed to establish a benchmark in the distribution of fished species across the Ningaloo Marine Park - Commonwealth (NMP-Commonwealth), and adjacent comparable habitats within the Ningaloo Marine Park - State (NMP-State), in Western Australia to test if there was evidence of an effect of recreational fishing, as no commercial fishing is allowed within either marine park. We also examined whether the remote location of the newly established (2018) No-take Zone (NTZ), in NMP-Commonwealth, limits its use for studying the effects of fishing. Throughout the NMP-Commonwealth and NMP-State, where recreational fishing is permitted, we expected the abundance of recreationally fished fish species to increase with increasing distance to the nearest boat ramp, as a proxy of recreational fishing effort. Conversely, we did not expect the abundance of non-fished species and overall species richness to vary in response to the proxy for human activity. Distance to the nearest boat ramp was found to be a strong predictor of fished species abundance, indicating that the effect of recreational fishing can be detected across the NMP-Commonwealth. The effect of the NTZ on fished species abundance was weakly positive, but this difference across the NTZ is expected to increase over time. Habitat composition predictors were only found to influence species richness and non-fished species abundance. This study suggests a clear footprint of recreational fishing across the NMP-Commonwealth and as a result the new NTZ, despite its remote location, can act as a control in future studies of recreational fishing effects.

A microplastics (MPs) emergence study in pelagic and mesopelagic species was carried out to delineate coastal degradation and ecosystem status around the Karachi metropolis. Species of high commercial and ecological worth were sampled using a gillnet of 1.5 cm knot-to-knot mesh size in November and December 2021. In total twenty-six individuals including Liza subviridis (15), Thryssa dussumieri (3), Rastrelliger kanagurta (2), and Portunus sanguinolentus (6) were used to perceive MPs. A strong linearity between body length and MPs (R2 = 0.937, SE 0.071 and R2 = 0.928, SE 0.104) were calculated for L. subviridis and P. sangiuilatus, respectively. However, the data of T. dussummeiri and R. Kanagurta showed minimization failure. The MPs in GIT were extracted using direct observation under a sophisticated binuclear microscope and chemical digestion (KOH) together with wet peroxide oxidation (H2O2+FeSO4) methods. The MP materials were categorized as foam, film, fiber, fragment, and beads of three different sizes 170, 120, 100 μm in the stomach, intestine, and esophagus. Film-type MPs appeared frequently, whereas beads were rarely seen. It is hoped that this baseline research would help to minimize industrial release, recognize critical knowledge gaps, and demonstrate MP flux being released into the aquatic environment. The results will support mitigation of this emerging threat to the living resources around the Karachi coastal area.

India Secures Seabed Mining Rights.

India Secures Seabed Mining Rights.

Australian cyclone downgraded but could rebuild: forecasters.

India makes its claim for sulphide mining from the Indian Ocean.

HUMPBACK whales (Megaptera novaeangliae) on their annual migration along WA's coast are facing pressure from both reduced food availability because of climate change and being disturbed by mining and boats, according to two studies.

HUMPBACK whales (Megaptera novaeangliae) on their annual migration along WA's coast are facing pressure from both reduced food availability because of climate change and being disturbed by mining and boats, according to two studies.

Why Kenya must take control of sand harvesting off its coast.

Une série de films et de photographies du monde entier qui vise à enrichir notre connaissance, notre appréciation et notre compréhension de l'économie bleue.

Asia's hunger for sand takes a toll on endangered species.

Reprieve for ABBOTT's booby after Christmas Island mining expansion ruled out.

A new study from The Australian National University (ANU) has shown the impact phosphate mining is having on our coral reefs.