The work deals with the oogenesis, spermatogenesis and associated reproductive structures of the little Indian squid Loliolus (Loliolus) hardwickei. Histological descriptions of the ovary, oviduct, testis and needham sac were made, the various changes observed during maturation were described and the functional significance was discussed. The female reproductive system consists of the ovary, glandular oviduct, lace-like oviducal funnel, paired nidamental gland, accessory nidamental glands and a seminal receptacle for sperm storage on the ventral side of the buccal cavity. The average size of the cells of the ovary varied from 7.635±3.466 µm (primary oogonia) to 1191.114±288.188µm (Ripe oocyte). Oocyte resorption or the presence of atretic oocytes was observed in some sections. The male reproductive system consists of the testis, vas deferens, spermatophoric organ, spermduct, the system of spermatophoric glands (SG) and spermatophoric sac (Needham sac) and penis. The spermatogenesis passed through the differentiation of primodial germ cells, primary and secondary spermatogonia, primary and secondary spermatocytes, rounded spermatids, and elongated spermatids to spermatozoa or sperms. The testis is connected to a thin-walled Needham sac by the spermatophoric duct. The testis is made up of numerous seminiferous tubules and is enveloped by tunica albuginea made up of connective tissue. Histological authentication of reproductive structures in L(L) hardwickei serves the specific purpose of providing a detailed understanding of the species' reproductive biology, which has implications for ecological, environmental, and conservation management efforts.

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Taxonomic ambiguity still exists in ariid catfish species identification. Morphological similarities occur in ariid catfishes which lead to misidentification of the species. To overcome this taxonomic ambiguity osteology is one of the effective integrated taxonomic tools for species discrimination. From this study, we provide an osteotaxonomic key for the field identification of ariid catfish species.The present paper deals with a comparative study of the five Ariidae family species discussed, they are Arius arius (Hamilton, 1822), Plicofollis layardi (Gunther, 1866), Netuma thalassina (Ruppell, 1837), Nemapteryx caelata (Valenciennes, 1840) and Osteogeneiosus militaris (Linnaeus, 1758). The osteological portions used for this study like premaxillary, dentary, neurocranium, otolith, vertebral and caudal bone. The aforementioned osteological portions made the important primitive characters that will be used to differentiate the species.

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Prolonged exposure of human dermal fibroblasts (HDF) to ultraviolet (UV) radiation triggers the production of reactive oxygen species by upregulating the expression of matrix metalloproteinases (MMPs), causing type-I collagen degradation and photoaging. A sulfated (1 → 3)/(1 → 4) mannogalactan exopolysaccharide (BVP-2) characterized as [→3)-α-Galp-{(1 → 4)-α-6-O-SO3-Manp}-(1 → 3)-α-6-O-SO3-Galp-(1→] was isolated from seaweed-associated heterotrophic bacterium Bacillus velezensis MTCC13097. Whole genome analysis of B. velezensis MTCC13097 (Accession number JAKYLL000000000) revealed saccharine biosynthetic gene clusters for exopolysaccharide production. BVP-2 administered cells showed noteworthy reduction in mitochondrial superoxide (∼85 %, p < 0.05) and ROS production (62 %) than those exhibited by UV-A irradiated HDF cells. Oxidative imbalance in HDF cells (after UV-A exposure) was recovered with BVP-2 treatment by significantly downregulating nitric oxide (NO) production (98.6 μM/mL, 1.9-fold) and DNA damage (?67 %) in comparison with UV-A induced cells (191.8 μM/mL and 98.7 %, respectively). UV-irradiated HDF cells showed a ∼30-50 % downregulation in the expression of MMPs (1, 2, and 9) following treatment with BVP-2. Considerable amount of sulfation (18 %) along with (1 → 3)/(1 → 4) glycosidic linkages in BVP-2 could be pivotal factors for down-regulation of the intracellular MMP-1, which was further supported by molecular docking and structure-activity studies. The (1 → 3)/(1 → 4)-linked bacterial exopolysaccharide (BVP-2) might be used as prospective natural lead to attenuate and mitigate UV-A-induced photoaging.

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The needlefish genus Ablennes remains monotypic, characterized by the globally distributed flat needlefish known as Ablennes hians. Their taxonomy has been mired with ambiguities due to the greater-than-average morphological variations observed in samples from different regions. Utilizing integrated taxonomic methods relying on mitochondrial molecular markers, it was revealed that the species initially perceived as a single entity is, in fact, a complex comprising at least three different species. In this context, we introduce two new species: Ablennes joseberchmansis sp. nov. and Ablennes gracalii sp. nov., They are morphologically distinct: in view of the morphometry and meristic characteristics. A. joseberchmansis sp. nov. and A. gracalii sp. nov. display distinct differentiation characteristics from A. hians in terms of dorsal fin, nostril position, dorsal fin origin, vertebrae count, scale counts, head length, eye diameter, interorbital width, maxilla length, dorsal ray height, depth at pelvic origin, lower lobe of the caudal fin, and caudal peduncle depthcaudal peduncle depth. These variations highlight their unique morphological traits and aid in their differentiation within the genus Ablennes. We assessed genetic relationships using a Maximum likelihood (ML) phylogenetic tree, revealing three distinct clades of morphological differences in Ablennes specimens from different morphological groups. The genetic variation, as represented by Kimura 2 parameter (K2P) distances, within the three Ablennes species spans from 6.5% to 9.4%. More specifically, we observed a 7.5% genetic difference between A. hians and A. joseberchmansis sp. nov., and a 6.5% distinction between A. hians and A. gracalii sp. nov. The interspecies divergence between the two newly identified species measured at 9.4%. These findings, which showcase the genetic distinctions among the three morphologically distinct Ablennes specimens, provide strong confirmation for the existence of three separate species within the Ablennes genus of needlefish in the Indian Ocean.

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Observations and analysis of the food and feeding habits of penaeid shrimp are decisive for understanding food webs and ecological processes. Published information on the feeding habits of the green shrimp, Penaeus semisulcatusDe Haan, 1844, from Indian waters, however, dates back four decades, despite the fact that green tiger shrimp is one of the important shrimp species that forms a unique fishery in Palk Bay, on the southeastern India. Hence, its dietary preferences were analysed concerning sex, season, gonad maturity, and size. The species preyed on were composed of diversified components, with mollusc remains being the most common food item in females, followed by crustacean remains, whereas in males, the crustacean remains were the most common food items followed by mollusc remains. There was no significant difference in the gastrosomatic index of females and gonadal maturity stages among seasons, but a significant difference among size groups. In males, there was no significant difference among seasons, gonadal maturity, and size groups. Females were more active feeders than males, and the difference could be seen in their size groups. Larger groups fed more actively than smaller groups. Feeding was more active in the post-monsoon and summer monsoon seasons. Penaeus semisulcatus dominates the ecosystem among the shrimp species due to its carnivorous behaviour. The observations made in this study form key inputs for trophic modelling and ecosystem-based studies, which could help develop suitable strategies for managing the shrimp resource in Palk Bay.

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Marine bacterial strains (number = 105) isolated from marine crabs were evaluated through a stepwise strategy incorporating the crucial attributes for therapeutic safety. The results demonstrated the potential of eight bacterial species for extracellular L-asparaginase production. However, only one isolate (Bacillus altitudinis CMFRI/Bal-2) showed clinically desirable attributes, viz. extracellular production, type-II nature, lack of concurrent L-glutaminase and urease activities, and presence of ansZ (functional gene for clinical type). The enzyme production was 22.55 ± 0.5 µM/mg protein/min within 24 h without optimization. The enzyme also showed good activity and stability in pH 7–8 and temperature 37°C, predicting the functioning inside the human body. The Michealis-Menten constant (Km) was 14.75 µM. Detailed in silico analysis based on functional gene authenticating the results of in vitro characterization and predicted the nonallergenic characteristic of the candidate. Docking results proved the higher affinity of the shortlisted candidate to L-asparagine than L-glutamine and urea.

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A new conceptual framework based on satellite data, including chlorophyll (CHL), sea surface temperature (SST) fronts, relative winds, current vectors, Ekman transport, and eddies, has been developed to identify potential fishing zones (PFZ) in the Bay of Bengal (BoB). The framework aims to provide persistent forecasts, even under cloudy conditions, based on feature propagation. The validation of the PFZ was carried out using fish catch data collected by the Fishery Survey of India (FSI) between 2016 and 2018. Hooking rates (HR) from longlines and catch per unit effort (CPUE) from trawl nets were used to analyse the data points in hook rate categories (1.0–3.0 and > 3.0) and CPUE categories (50–100 kg and > 100 kg) and interpret them with the PFZ maps. The analysis showed that the high fish catch locations were consistent with persisting features in the BoB, such as high chlorophyll patches, SST fronts, and cyclonic eddies. The high fish catch locations based on hook rate and high CPUE were found to be collocated with the high chlorophyll persisting features and thermal gradients in the BoB. The regression analysis shows that availability of the food (CHL) had the strongest correlation with fish catch, followed by the comfort condition (fronts and eddies).

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Studies on elasmobranch trade have often focused on a single commodity, shark fins. Such a narrow focus can result in an incomplete understanding of the socio-cultural importance of sharks, limiting discussion on the range and efficacy of potential management interventions. Assessments must be performed across the value chain from fisher to retail vendor to better conserve vulnerable elasmobranch species, offering a broader view of capture, use, and trade. Here, we collate insights from shark value chain assessments conducted in eight countries (Mexico, Peru, Guinea-Bissau, India, Bangladesh, Sri Lanka, Indonesia and Fiji) spanning five continents. Approaches and processes implemented in a shark value chain analysis (VCA) were reviewed to: (1) understand better approaches and tools and (2) collate shared experiences. Our results demonstrate that VCAs broaden the outlook of fishery and trade assessments when capturing a more comprehensive range of economic and socio-cultural aspects (e.g., livelihoods, cultural use of commodities) of trade in all shark commodities. Time invested in various components of assessments produced different outcomes, with considerable returns from stakeholder selection, survey design, and assessor/stakeholder relationship building. Contrastingly, results demonstrated that efforts in communication with stakeholder groups and policymakers could be further streamlined to focus on key results using a variety of communication formats. Outcomes from this study offer guidance to those embarking on shark VCAs, facilitating improving the assessment process and outcomes.

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Nemipterus randalli, commonly known as Randall’s threadfin bream, is a commercially important marine finfish. Understanding its genetic structure is critical to effective management and conservation efforts. Previous investigations on population structure in this species were limited by geographic coverage. In this study, we utilized the mitochondrial Cytochrome b gene and nuclear Ribosomal protein gene intron Rp S7 sequences to investigate the population genetic structure, demography and genetic diversity of N. randalli along Indian waters. Our results revealed high haplotype diversity but low nucleotide diversity. AMOVA revealed that the variation among the population was highly significant. Hierarchical AMOVA provided further evidence of significant genetic differentiation between the west and east coasts, which was corroborated by the Bayesian tree and the median-joining network diagram. The mtDNA sequences revealed significant genetic structure between populations based on fixation index analysis following the isolation-by-distance model. Furthermore, the neutrality test and mismatch analysis suggest that N. randalli populations may have experienced a population expansion. However, nuclear marker RpS7, showed a high level of polymorphism, which obscured the population structuring observed with the mitochondrial marker. Consequently, concordant results were not obtained when comparing the mitochondrial and nuclear DNA sequences. The strong genetic differentiation between the east and west coast observed using mitochondrial marker could be attributed to a combination of geographic and environmental factors. These findings lay the groundwork for developing effective conservation and management strategies for N. randalli, considering its genetic structure.

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Artisanal fishers fishing in nearshore coastal waters off Visakhapatnam using motorised crafts and in estuaries of Krishna using non-motorised crafts were selected for the study. Their annual net operating income varied between US$ 469.63 (?39,040) and US$ 2698.42 (?2,24,320), respectively. Inspired by the potential of cage farming from the frontline demonstrations in marine and estuarine waters and after acquiring appropriate skills, 15 individuals from the Traditional Fishermen’s Co-operative Society, Visakhapatnam and 76 individuals from Yanadri Girijana Matsya Sakhara Sangam, Krishna embarked on cage aquaculture of Indian pompano in 15 and 70 cages, respectively. Marine cages were circular (6 m diameter) and estuarine cages were square (5 m X 5 m), and were stocked with hatchery-produced Indian pompano (Trachinotus mookalee) fingerlings of 22.6 g weight @ 2500 and 1500 numbers respectively, and were fed with floating pellets at 8-3% of biomass. Average body weight, survival and biomass production from marine and estuarine cages after eight months of culture were 843 and 666 g, 96.28 and 91.47% and 2029.0 and 913.85 kg respectively. Deducting all capital and operational expenses, annual net operating income per unit ranged from US$ 1247.44 (?1,03,700) to US$ 2632.02 (?2,18,800); which represented a substantial increase from that of capture fishery. Cluster-cage farming, as adopted, did not adversely impact the water and sediment quality. The current research offers novel insights into the bio-growth and economic factors pertinent to commercial cage farming of Indian pompano. Cage farming in marine and estuarine conditions holds a great promise as an alternative source of livelihood for artisanal fishers, thereby bolstering their economic sustainability.

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The sawtooth barracuda Sphyraena putnamae, widely distributed in the Indo-Pacific region, is one of the commercially important barracuda species exploited by trawls in the Indian EEZ. The present study examined 2,135 S. putnamae collected during 2014-2020 from different fish landing centres along the Indian coast, to elucidate their reproductive and feeding behaviour. The fork length of sampled females and males varied from 12.5 to 130.9 cm and 16.5 to 90.0 cm respectively. Negative allometric growth was observed with a significant difference (p<0.05) between the sexes. The observed sex ratio (Female:Male) was 1.23:1, indicating the dominance of females. Size at sexual maturity for females and males were estimated at 55.3 and 45.4 cm fork length respectively. The higher proportion of spawning capable individuals and higher gonadosomatic index (GSI) values in females observed during March to May and November-December revealed the bimodal and protracted spawning nature of this species. Absolute fecundity increased with fork length and weight and varied from 70,080 to 10,18,068 oocytes with an average of 3,16,568 oocytes. The stomach vacuity index of females and males was 49.09 and 47.92% respectively. Fifty-nine prey items were identified in the diet, with a predominance of fishes confirming S. putnamae has a piscivorous feeding behaviour.

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Deep investigations of host-associated microbiota can illuminate microbe-based solutions to improve production in an unprecedented manner. The poor larval survival represents the critical bottleneck in sustainable marine aquaculture practices. However, little is known about the microbiota profiles and their governing eco-evolutionary processes of the early life stages of marine teleost, impeding the development of suitable beneficial microbial management strategies. The study provides first-hand mechanistic insights into microbiota and its governing eco-evolutionary processes in early life stages of a tropical marine teleost model, Trachinotus blochii.

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The Ashtamudi short-neck clam forms a significant fishery resource holding India’s first Marine Stewardship Council Certification. The taxonomic classification of this particular clam has engendered debate regarding its proper nomenclature. The present study aims to provide its first comprehensive mitogenome profile from the type locality to address the existing taxonomic ambiguity. The mitogenome assembled using the genome skimming method had 17,991 base-pair length with 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs and control region. Phylogenetic analysis based on the concatenated data set of PCGs and rRNAs from 47 representative species of Veneridae grouped all species including short-neck clams from the subfamily Tapetinae into a single clade. This analysis also revealed the polyphyly of the genus Marcia. Nevertheless, the short-neck clam co-clustered with Marcia recens from Chinese waters.

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Studies on Pomadasys maculatus collected from the southwest coast of India showed fishes in the length range 130-197 mm with a mean standard length of 139.41 mm and body weight of 79.09 g. The growth pattern observed was isometric. P. maculatus shows no sexual dimorphism. Since there is no recent information on the morphometric and meristic characteristics of P. maculatus from India, the present study is expected to add more knowledge to the species.

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The study focused on the fishery and biological aspects of the spotted sardinella Amblygaster sirm (Walbaum, 1972) exploited along the southern coast of India from 2015 to 2020. The summary of the fishery reveals noticeable annual fluctuations in landing, with peak landings reported from November to March along the coast. The study included fish with total length (TL) ranging from 149 to 208 mm in males and 152 to 217 mm in females. The peak in gonadosomatic Index (GSI) in January indicates its spawning season, and Lm50 was estimated at 172 mm TL in females. The sex ratio (F: M) was determined at 1:1.2, with males dominating most months. Fecundity ranged from 11632 to 43200 eggs per spawning. Five stages of maturity in A. sirm were identified through external analysis of gonads. Seven histological ovarian stages of A.sirm were recorded, providing a primary reference for future studies. These findings aim to assist fishery managers and policymakers in adopting effective management practices for the sustainable harvesting of this resource.

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Sharks have thrived in the oceans for 400 million years, experienced five extinctions and evolved into today’s apex predators. However, enormous genome size, poor karyotyping and limited tissue sampling options are the bottlenecks in shark research. Sharks of the family Orectolobiformes act as model species in transcriptome research with exceptionally high reproductive fecundity, catch prominence and oviparity. The present study illustrates a de novo transcriptome for an adult grey bamboo shark, Chiloscyllium griseum (Chondrichthyes; Hemiscyllidae) using paired-end RNA sequencing. Around 150 million short Illumina reads were obtained from five different tissues and assembled using the Trinity assembler. 70,647 hits on Uniprot by BLASTX was obtained after the transcriptome annotation. The data generated serve as a basis for transcriptome-based population genetic studies and open up new avenues in the field of comparative transcriptomics and conservation biology.

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The present study addresses the crucial sustainability concerns in small-scale fisheries (SSF) against the backdrop of escalating anthropogenic activities and climate change impacts on marine fishery and ecosystems. Our study focused on a traditional fishery exploitation area spanning 12,646.12 km2 along the Southwestern Coast of Kerala, India, and explored four widely used fishing gears. We established an integrated decision-making VIKOR framework, and preferential modelling by incorporating techno-economic and environmental aspects to draw the optimal solutions. Leveraging 10 sustainability indicators, the boat seine emerged as the most sustainable gear, showcasing significant profitability (US$ 16,126/year−1 net profit) and remarkable energy efficiency, surpassing gillnetters, longliners, and shore seiners by 8.4, 4.9, and 3.0 times, respectively. The Fuel Use Intensity (FUI) and CO2 emissions analysis (F value = 58.37, P < 0.0001) emphasizes the ecological implications. 

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Kumar, Rajan and Dash, Gyanaranjan and Muktha, M and Sasikumar, Geetha and Ganga, U and Kizhakudan, Shoba Joe and Chellappan, Anulekshmi and Bhendekar, S N and Sukumaran, Sandhya and Thomas, Sujitha and Varghese, Eldho and Abdussamad, E M and Josileen, Jose and Dash, Swatipriyanka Sen and Rahangdale, Shikha and Pillai, S Lakshmi and Remya, L and Akhilesh, K V and Chakraborty, Rekha D and Rajesh, K M and Najmudeen, T M and Kuriakose, Somy and Mini, K G and Purushottama, G B and Kavitha, M and Vidya, R and Nakhawa, A D and Vinothkumar, R and Roul, Subal Kumar and Mahesh, V and Wilson, Livi and Divipala, Indira and Jasmin, F and Abdul Azeez, P and Surya, S and Koya, Mohammed and Manas, H M and Vase, Vinay Kumar and Rajkumar, M and Dineshbabu, A P and Sarada, P T and Venkatesan, V and Nair, Rekha J and Pradhan, Rajesh Kumar and Gomathi, P and Sunil Kumar, S Ali and Margaret Muthu Rathinam, A and Laxmilatha, P and Ghosh, Shubhadeep and Jayasankar, J and Gopalakrishnan, A (2024) Assessment of marine fish stocks within India’s Exclusive Economic Zone: Status report 2022. Indian Journal of Fisheries, 71 (1). pp. 1-11. ISSN 0970 - 6011

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