Ingestion of polysaccharide from microalga-derived ‘super food’ Spirulina as a dietary supplement can benefit human health against several chronic disorders. A sulfated heteropolysaccharide with [→4)-α-GlcAp-(1 → 2)-α-Rhap-(1→] as key structural moiety and [(3 → 1)-6-O-SO3-β-Glcp] (SPP-3) as lateral branch, was obtained from microalga Spirulina platensis. SPP-3 exhibited potential anti-thyroid activities by reducing serum cardiovascular risk indices and protein oxidation and nitration in vital tissues of methimazole (MTZ)-induced hypothyroid rats. Upon treatment with SPP-3 (50 mg/kg BW), hypothyroid biomarkers, such as thyroid stimulating hormone (TSH, 5 μIU mL−1), triiodothyronine (T3, 4.55 ng dL−1) and thyroxine (T4, 4.18 μU dL−1) were significantly recovered in comparison with MTZ-induced hypothyroid rats (7.74 μIU mL−1, 2 ng dL−1, 2.49 μIU mL−1, respectively). The level of serum cardiovascular risk indices (CV-I and II) of diseased rats was significantly reduced following the administration of SPP-3 (lesser than 12 %, p < 0.05) compared to the hypothyroid-induced group of animals (18–21 %). SPP-3 substantially downregulated protein nitration (46–49 %) and oxidation (37–39 %) levels in vital tissues than those exhibited by diseased control (90 and 65 % for protein nitration; 81 and 52 % of protein oxidation). Therefore, the microalgal rhamnoglucan (SPP-3) might be utilized as a promising naturally derived food-based carbohydrate biopolymer for health benefits against hypothyroid disorders.

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This study provides the first report on the length-weight relationship, reproductive biology and diet of Pomadasys kaakan (Cuvier, 1830) from western Bay of Bengal. Specimens for the study were collected from two locations, Visakhapatnam and Puri, with 301 fishes collected from the former and 153 from the latter. The mean size of P. kaakan at Visakhapatnam was 38.7 cm total length (TL) and 32.07 cm TL at Puri. The length-weight relationship indicated negative allometric growth in the species from both locations. The length at first maturity for female fish was estimated to be 31.5 cm TL at both locations. Our study indicated spawning throughout the year with peaks in February-April and July-August for P. kaakan in the study area. Analysis of diet indicated that in the study region the species had divergent feeding habits. At Visakhapatnam, teleosts (unidentified finfish, eels and silverbellies) were dominant diet items whereas crustaceans (crabs and shrimps) were the dominant diet components of P. kaakan at Puri. The close similarity in size distribution and reproductive biological parameters from the two regions points towards the possibility of a single stock of the species in the study region.

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Sea cage farming in marine open waters is considered as the most viable technique in Indian mariculture to enhance production. Owing to the support of the government in research and development, and policy initiatives, marine cage farming is progressing steadily in the country. Technological guidance from research institutions and financing under the ambitious “Pradhan Mantri Matsya Sampada Yojana (PMMSY)” and blue growth mission objectives have inspired stakeholders and fisheries administrators in maritime states to explore open sea cage culture. Site selection is a key parameter affecting the success of cage culture systems and, technically analysed geo-referenced demarcation of spatial information is necessary for minimising the risks. Thus, in the light of rising demand for spatial allocation of coastal areas, the present study identifies and aggregates locations within 3 km of the coastline, that have the potential for sea cage farming operations in the country. The site suitability was examined based on optimal standards required for the prospective candidate species selected for mariculture in India. The locations were vectorised in a GIS platform, and the potential areas available for sea cage installations were demarcated. An optimised site suitability schema was developed for the spatial demarcation of potential site selection.The preliminary results identified 134 sites covering a total area of 46,823.2 ha suitable for marine cage culture along Indian territorial waters. Among the coastal states, the top three states holding the maximum area suitable for sea cage farming are Andhra Pradesh (11,792 ha), Gujarat (11,572.2 ha) and Tamil Nadu (7,673 ha). It is envisaged that spatial suitability demarcation even on this pilot scale will accelerate the expansion of sea cage farming in the country.

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In light of the ecological concerns associated with bottom trawling in tropical multispecies fisheries, an attempt was undertaken to implement operational modifications in experimental trawling practices aimed at reducing bottom contact. This endeavour was pursued to investigate the resulting effects on bycatch biomass and diversity along the north-western Bay of Bengal. The average total catch rate and bycatch rate in 66 hauls from January 2017 to December 2019 were 35.46 kg/h and 9.70 kg/h respectively. Bycatch biomass was mainly contributed by Teleostei (77.90%), of which the dominant species was Equuilites lineolatus. Temporal variations in bycatch composition were recorded, and average seasonal dissimilarity ranged between 35.03% and 59.61%. Juvenile percentages varied among six commercial species from 1.42 to 28.0, and their occurrences were related to their peak spawning seasons. The trophic index of bycatch calculated was 3.65. Species diversity and richness in bycatch were higher during post-monsoon and summer seasons. Biomass and abundance plots indicated the bycatch fauna to be relatively unstressed during most seasons. Trawling marginally above the bottom had improved ecological outcomes; as evident from the decreased proportion of bycatch to total trawl catch, reduced growth overfishing from lower juvenile proportions and within optima for various diversity indicators.

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In past decades, non-native species invasion has emerged as one of the leading drivers of biodiversity loss in terrestrial and aquatic ecosystems globally. In aquatic ecosystems, invasion by bivalve species has increased substantially due to their evolutionary resilience and adaptability. This study aimed to determine the habitat suitability of the South American bivalve Mytella strigata in the northern Indian Ocean using Species distribution modelling. The species occurrence and environmental data for model building were extracted from GBIF, Bio-ORACLE, The World Bank Data Catalogue and GMED. Pearson's correlation (<0.7) and Variance inflation factor (<10) analyses were used to select the environmental covariates. Individual models were built by combining the native range occurrence data of Mytella strigata with the bioclimatic data under the current climatic setting. Ten individual models were built and ensembled to create the final model using the biomod2 package. The variable importance score and the response curve plot were used to identify the most crucial variable and its influence on the models. Distance to port had the highest influence on predicting the distribution of Mytella strigata. The results indicated that the western coast of India as more susceptible to invasion. Our predictions indicate that the species has the potential to become highly invasive in the region, given the vast habitat suitability and documented introduction and presence of the species in the region. This research generated baseline information on the habitat suitability of M. strigata that will aid in managing and restricting its spread in the region. Considering the substantial impact of the species in other introduced ranges worldwide, immediate action should be initiated for the swift management of M. strigata from the Indian coast.

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