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Defining the ecological quality of estuaries is challenging because of the inadequacy of available methods and indices to characterise the ecosystem. In Indian estuaries, there are no scientific attempts to establish multi-metric fish index to determine the ecological status. A multi-metric fish index (EMFI) was customised for twelve predominantly open estuaries on India's western coast. The index was established at the individual estuary level to ensure uniformity and contrast from sixteen metrics that designate the fish community and diversity, composition and abundance, estuarine use and trophic integrity from 2016 to 2019. A sensitivity study was followed to measure the responses of the EMFI under different metric varying scenarios. There were seven metrics identified as the most prominent for the EMFI in metric alteration scenarios. We also deduced a composite pressure index (CPI) based on the anthropogenic pressures described for the estuaries. The ecological quality ratios (EQR) defined based on EMFI (EQRE) and the CPI (EQRP) for all the estuaries were positively correlated. The EQRE values calculated based on the regression relationship (EQRE on EQRP) showed the divisions from 0.43 (bad) to 0.71 (high) for the Indian west coast estuaries. Similarly, the standardised CPI (EQRP) values for different estuaries indicated that the values range from 0.37 to 0.61. Our results based on the EMFI suggest four estuarine systems (33%) as 'good', seven (58%) as 'moderate' and one (9%) as 'poor'. Generalised Linear Mixed Model for EQRE showed that EQRP and estuary influenced EQRE; however, the effect of year was not significant. This comprehensive study based on the EMFI is the first record for predominantly open estuaries along the Indian coast. Therefore, the EMFI established in this study could be reliably advocated as a sound, effective and composite tool of ecological quality for tropical open transitional waters. [ABSTRACT FROM AUTHOR]

Invasive alien species (IAS) influence the trophic organisation and food web structure in an invaded ecosystem, and therefore, it is imperative to quantify the resultant ecological impacts. The globally recognised ecosystem modelling platform, Ecopath with Ecosim, was used to delineate the impacts of IAS on a tropical freshwater pond ecosystem in India. We analysed the trophic interactions, consumption patterns, prey overlap and mixed trophic impacts of three co-existing invasive alien fish species, African catfish (Clarias gariepinus), suckermouth catfish (Pterygoplichthys pardalis) and Mozambique tilapia (Oreochromis mossambicus), on other functional groups in the ecosystem. Together, the three IAS shared 11% of the total energy consumption and about 50% of the energy consumption by the fish species/groups. There was no predation mortality for African catfish and suckermouth catfish, and a very low estimate for the same was recorded for tilapia (0.64 year−1). The IAS shared high mean prey overlap with the native fish groups (Garra sp., Etroplus suratensis, Systomus sarana, Chanda nama and various small species of the cypriniform genera Puntius, Rasbora and Devario) indicating a substantial competition between alien and native species in the ecosystem. Consequently, the three IAS exhibited higher mean negative mixed trophic impacts on these functional groups. A very high Finn's cycling index (39.59%), a low relative ascendency (28.5%) and a very low system robustness (0.07) were observed compared to similar ecosystems, and the baseline values. These indices exposed the vulnerability of the ecosystem towards perturbations, which could be due to the presence of multiple alien invasive species. Mitigating the impacts of IAS should involve a combination of approaches, including eradication through draining and harvesting, high-density stocking of similar trophic level fish in the pond, and local and national level policy interventions. [ABSTRACT FROM AUTHOR]

The interest in deep-sea mineral resources has surged recently, driven by the increasing need for metals and the global push for sustainable, low-carbon energy sources under the 'blue economy' framework. The deepsea minerals include polymetallic nodules, cobalt-rich Fe-Mn crusts, and polymetallic sulphides, which contain high amounts of copper, nickel, cobalt and other valuable metals. These mineral deposits are often associated with unique and fragile ecosystems, which necessitates the development of mining technologies with minimal environmental impact. Here, we review the key deep-sea minerals, their resource potential, exploration aspects and the need for sustainable extraction, with a particular focus on India's exploration activities. [ABSTRACT FROM AUTHOR]

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Natural disturbances along with human interference make the tropical estuaries amongst the most disturbed areas globally. In spite of this, information on the seasonal variability of macrofauna from tropical estuaries is few. Temporal variability of macrofaunal community from Mormugao Bay, Zuari estuary, on the west coast of India was examined from 2003 to 2004 at seven stations. Environmental variability was assessed through physicochemical parameters of water and sediment. The changes in macrobenthic community were assessed using abundance, biomass and species diversity indices. The environmental parameters showed a significant seasonal variation influenced by monsoonal changes. The changes in the environmental conditions brought about variation in the macrobenthic community. Macrofaunal abundance, biomass and species diversity were the highest during post-monsoon influenced by recruitment. In monsoon, the macrobenthic community was dominated by polychaetes (92.17%), whereas bivalves dominated during the post-monsoon (57.7%). The macrofauna showed drastic decline during the stable pre-monsoon season, a period when the highest abundance of fauna is observed in the tropical estuary. Therefore, the macrobenthic community in the area did not follow the seasonal trend generally observed in a tropical estuary. Further, the community during pre-monsoon season was dominated by the opportunistic polychaete species indicating a possible influence of harbour activities in structuring the benthic community of the area. [ABSTRACT FROM AUTHOR]

The reproductive cycle of Polymesoda erosa was studied over a 12-month period from July 2004 to July 2005 at Chorao Island, Goa. Macroscopic observation revealed that P. erosa is dioecious and gametogenic development was synchronous between the sexes. Sexes can be determined at a total length of <34 mm, based on the colour of the gonads. The gonadosomatic index (GSI) indicated that gametogenesis began in November and by March-April most clams were ripe. Spawning began in August and by October nearly all clams were completely spent. Maturation and high GSI were observed to begin during the warm summer months with low GSI values in August (20.0) and September (22.0). Correlation between GSI and chlorophyll a content in the adjacent estuarine water suggests that gametogenesis in mud clam is directly related to the phytoplankton production. The condition index (CI), which is generally used to characterize the physiological activity of organisms, varied from 1.9 in September to 4.7 in March, with low values during the spawning period. The clams attained their best condition in quality of flesh weight during March-May. The data presented here should provide valuable information on the timing of spawning events for P. erosa, necessary for developing sustainable management strategies and broodstock selection, which is crucial in aquaculture development. [ABSTRACT FROM AUTHOR]

The article presents a study that deals with new species of marine littoral mites from Taiwan and India. Based on adult and juvenile specimens, the authors described two species of the small oribatid mite genus Fortuynia, Fortuynia taiwanica sp. nov. and Fortuynia arabica sp. nov. collected from the marine littoral zones in the tropics and subtropics. The study provided information on a diagnostic key to the adults of known species of Fortuynia in the world as well as a summary of their geographical distributions.

Estuaries provide enumerable ecosystem services to mankind in terms of provisional, regulating, supporting, recreational and information services. However, the persistent human-environment interactions for these services altered the ecological integrity of estuaries. Although the small estuaries receive little attraction in scientific studies due to their low surface area and regional importance, these ecosystems are more vulnerable to anthropogenic pressures and require urgent attention from the scientific fraternity. The Terekhol Estuary (TRE) is a small tropical estuary situated along Goa, west coast of India, gaining recognition in recent years due to the pollution risk from tourism activities. Moreover, the estuary also behaves as an extension of the marine realm during the dry season. The food web structure and network flow indices of the TRE was assessed to reveal its present ecological status. The Ecopath modelling approach was employed to delineate the ecosystem structure and trophic functioning of the estuary distributed in 22 ecological compartments from 2018 to 2019. The trophic level of the food web ranged from detritus (TL-1) to sharks (TL- 4.53). The ecosystem structure demonstrated a grazing chain (herbivory) based organization over the detritus-based pathway. The proportion of exports to the total flows was 35% for the TRE. The model has a high total system throughput (12,043.6 t km−2 year−1), low system omnivory index (0.17) and connectance index (0.21), and a moderate relative ascendency (45.1%). Finn's cycling index (2.17%) indicated very low recycling in the system. All these indicators along with the eco-exergy index (8567.22 g detritus equivalent m−2), specific eco-exergy (38.25) and robustness index (0.11) classified the estuary as be immature, less stable and less organized and is in the initial stages of its development. The ecological indicators analyzed here point towards a medium to a high level of impact in the TRE due to anthropogenic activities. We also highlight the management measures to be implemented in order to restore the ecological quality of the TRE. [Display omitted] • The food web model of a small tropical estuary, Terekhol along the west coast of India was constructed. • A grazing chain based on herbivory followed by detritivory was identified in the estuary. • The estuary is identified as an immature, low recycling and developing ecosystem. • The health and stability indices indicated a less stable and less organized stature of the ecosystem. [ABSTRACT FROM AUTHOR]

Chakraborty, B., Mahale, V., Navelkar, G., Rao, B. R., Prabhudesai, R. G., Ingole, B., and Janakirinam, G. 2007. Acoustic characterization of seafloor habitats on the western continental shelf of India. – ICES Journal of Marine Science, 64: 551–558.This is a study of the interaction effects of the dual-frequency (210 and 33 kHz) backscatter signal with seafloor sediment and benthic biota along a transect in water 27–83 m deep offshore of the Goa region of India's central west coast. Estimation of the power-law exponent using seafloor topographic data provided equivalent values even when using dual high-frequency systems for different grain-size sediments. Backscatter signals corrected from system-related gain, etc., reveal better correlations with sedimentary and benthic parameters than the estimated coherence parameters (using echo peaks). Statistically, correlations are significant for the 210 kHz backscatter signal with sand and calcium carbonate (CaCO3) sediment content. Also, correlations are higher for macrobenthic biomass (wet weight) and population density with a 210 kHz backscatter strength, emphasizing the dominant seawater–seafloor interface scattering process. For 33 kHz backscatter strength, the absence of such correlations indicates a different scattering process, i.e. dominant sediment volume scattering attributable to the comparatively lower signal attenuation. Additionally, to validate the results, the backscatter signals from other locations in the vicinity of this transect were considered. [ABSTRACT FROM PUBLISHER]

Globally, coral reefs have drastically degraded due to local and global environmental stressors. Concurrently, coral reef tourism is rapidly growing in developing economies, which is one of many anthropogenic stressors impacting reefs. At the Malvan Marine Sanctuary, a Marine Protected Area (MPA) on the West coast of India, we investigated the impact of recreational diving on the reef from 2016 to 2019. To evaluate the diver's underwater behavior, a novel approach was used, wherein the video-log broadcasting website www.youtube.com was perused. Evidential proof substantiates heavy physical damage to corals because of recreational diving activity, which may lead to the collapse of coral habitat if it continues unabated. This resource depletion ironically elevates the economy of dependents averting consequences due to lost corals, thus making this a ' tragedy' for corals which are not meant to be ' commons '. The study asserts need for proactive conservation efforts with stringent implementation and restoration initiatives in this MPA. Unlabelled Image • Results reveal heavy coral damage due to direct diving activity by tourists. • youtube.com videos proved diver's underwater behavior detrimental to corals. • Local economy uplifts on the mercy of coral habitat loss. • It's a ' tragedy' but not making the ' commons' to suffer due to elevated economy. • Regulations based on diving carrying capacity required to protect the reef. [ABSTRACT FROM AUTHOR]

Globally, coral reefs are degrading rapidly due to the combined impact of wide-scale anthropogenic activities and climate change. Similarly, coral reefs in India are facing an existential threat because of intensified environmental degradation, which challenges reef ecosystem resilience and socio-ecological stability. Recently, Govt. of India has taken up the 'SagarMala Programme' aiming to increase its port capacity by the expansion of existing ports, construction of several new ports and allied infrastructure development by 2025. Synergistic impact of coastal development coupled with the on-going environmental changes is deemed to accelerate coral reef degradation in Indian reefs. Therefore, the present article aims to highlight the urgency of positive intervention and initiation of long-term holistic coral reef restoration program as an active reef management tool. Along with conventional management practices, reef restoration program could curtail further reef degradation and will ensure the persistence of Indian coral reefs and the services they provide. • Corals in India are stressed by increasing human perturbations and climate change. • Studies and projections indicate shortfall in traditional conservation practices. • Scientific restoration techniques to be employed to sustain coral reefs in India • Coral translocation can ameliorate possible dire impacts by coastal development. • Financial commitments of reef restoration projects may be secured from the developers. [ABSTRACT FROM AUTHOR]

A response from the authors of the article regarding the possible impact of the bleaching event in Malvan, India on the fishery and tourism in the 2015 issue is presented.

Abstract: Acoustic backscatter from multi-beam echo-sounder (MBES) and dual-frequency single-beam echo-sounding systems (SBES) operable at 95kHz and 33/210kHz, respectively, were used to study the distribution of sediment texture and benthic macro-fauna along the central part of the western continental shelf of India (off Goa). To characterize the continental shelf seafloor, single-beam and multi-beam backscatter signals were acquired along with grab sediment samples. The relationships between processed acoustic backscatter strength, grain size, and benthic macro-fauna abundance were demonstrated employing clustering technique (PCA) and Geographic Information System (GIS) based mapping. The clustering analysis delineated that the backscatter values at three frequencies are strongly correlated with both substrate type and faunal functional groups. The preferences of deposit feeders (soft body benthic macro-fauna) for the fine-sediment regions and filter feeders (hard body benthic macro-fauna) for coarse sediment regions were linked to the variations in sediment granulometry as well as backscatter strengths in the study area. This study further demonstrates the utility of high frequency backscatter data employing echo-sounding systems towards the interpretation of seafloor sediments and benthic habitat characteristics across large areas of seafloor. [Copyright &y& Elsevier]

In this study, we evaluate the fish-based ecosystem services (ES) of Chettuva, a small tropical estuary (CE) on the south-west coast of India. Besides the direct benefits (provisioning and cultural), the primary regulatory and supporting services provided by fish in estuaries were also documented using secondary data and focused group discussions (FGD). The major obstacles impeding the fisheries-based ES were also identified, and priority-based management options were proposed. The annual economic value of the major fish-based ES of the estuary was estimated to be ₹814.55 million (₹36.96 million for provisioning, ₹569.52 million for supporting, ₹177.6 million for regulating and ₹30.47 million for cultural and information services including recreation, tourism, scientific and information services, respectively). The estuarine fishery in CE is still traditional, employing non-motorized boats and supporting the livelihood of about 300 active fishers. Our findings revealed that stakeholders rated higher values on provisioning, supporting, and cultural services while providing little significance on the regulating services. The current findings indicated that, as the primary means of livelihood, fisheries not only provide a pragmatic overview of the economic value of estuarine systems but also signifies the use of fisheries-based ES as a valuable tool in developing an ecosystem-based management plan. Based on the findings, it would be reasonable to highlight the need for ES-based approach for resource conservation in fisheries management of the small tropical estuaries. • The fisheries-based ecosystem services of a small tropical Indian estuary-Chettuva were evaluated. • The estuary has a subsistence fishery with 300 fishers with an income of ₹16.54 million. • Stakeholders focus on provisioning, supporting, and cultural services than regulating type. • The annual economic value of ecosystem services was estimated to be ₹814.55 million. • The challenges and management measures for efficient delivery of ES are discussed. [ABSTRACT FROM AUTHOR]

Underwater sampling via SCUBA and grab at the Angria Bank coral reefs off the central west coast of India in January 2014 revealed 11 species of Brachyura. Seven species, namely, Thusaenys irami (Laurie, 1906), Tanaocheles bidentata (Nobili, 1901), Portunus convexus De Haan, 1835, Xiphonectes macrophthalmus (Rathbun, 1906), Thalamita gatavakensis Nobili, 1906, Serenius ceylonicus (Laurie, 1906), and Soliella flava (Rathbun, 1894) are reported for the first time from Indian waters. Furthermore, the geographical distribution of T. irami and S. ceylonicus is extended westwards of hitherto known ranges.

The bacterial diversity associated with eroding sponges belonging to the Cliona viridis species complex is scarcely known. Cliona thomasi described from the West Coast of India is a new introduction to the viridis species complex. In this study, we determined the bacterial diversity associated with C. thomasi using next-generation sequencing. The results revealed the dominance of Proteobacteria followed by Cyanobacteria, Actinobacteria and Firmicutes. Among Proteobacteria, the Alphaproteobacteria were found to be the most dominant class. Furthermore, at the genus level, Rhodothalassium were highly abundant followed by Endozoicomonas in sponge samples. The beta-diversity and species richness measures showed remarkably lower diversity in Cliona thomasi than the ambient environment. The determined lower bacterial diversity in C. thomasi than the environmental samples, thus, categorized it as a low microbial abundance (LMA). Functional annotation of the C. thomasi-associated bacterial community indicates their possible role in photo-autotrophy, aerobic nitrification, coupling of sulphate reduction and sulphide oxidization. The present study unveils the bacterial diversity in bioeroding C. thomasi, which is a crucial step to determine the functions of the sponge holobiont in coral reef ecosystem.

Short and long term effects of a fuel oil spill from a grounded ship "M V Sea Transporter" on meiofauna of a sandy beach of central West Coast of India were investigated. A significant reduction in the absolute abundance of meiofauna was observed immediately after 3 days of spillage particularly at Sinquerim beach, the site of spillage. The reduction was most pronounced in density of nematodes and harpacticoid copepods, which were the most dominant groups. Long-term response showed no apparent oil-induced changes at major taxa levels. The population density improved considerably after the cessation of monsoons with a parallel decrease in petroleum hydrocarbon concentration in the sediment. Nematodes recovered more quickly than benthic copepods. No evidence for this could be due to reproductive dynamics in meiobentos. Although the effect of the oil on meiofauna could be seen initially it could not be proved conclusively on a long-term basis. The effects of the oil spill were confounded with seasonal monsoon effects and beach dynamics. The nematode:copepod ratio and the index of trophic diversity (ITD) were inadequate for detecting oil pollution effects. Therefore it may be concluded that in the presence of other environmental factors acting strongly, the effects of oil on meiofauna was strong but of a temporary nature.