In this study, a new brain cell line designated PB1BrTr was derived from the maroon clownfish Premnas biaculeatus (Bloch, 1790) and characterised. The PB1BrTr cell line was developed by trypsinisation method using Leibovitz’s L15 (L-15) medium supplemented with 20% FBS (foetal bovine serum) and subcultured over 100 times. Characterisation encompassed studies on optimal growth kinetics, chromosomal analysis and genotyping of the mitochondrial CO1 gene. A high revival rate (85-95%) and good attachment during seeding after a year of cryostorage demonstrated the high stability of the cell line. This cell line exhibited good seeding efficiency of 84% at 1.25 x 105 cells ml-1 and a range of plating efficiencies from 14-23% at varying cell densities. It was observed that 28 degree C was the ideal temperature for its growth. Serum requirement decreased with increased passage and lowered to 2% FBS beyond 60 passages. However, higher serum concentration (2-20%) caused a concurrent increase in cell growth. The cell line displayed a fibroblast-type morphology, with immunotyping results revealing robust reactivity towards the fibroblast marker. Chromosome analysis of this cell line revealed aneuploidy and its authenticity was validated by mitochondrial Cytochrome C Oxidase Subunit I (COI) genotyping analysis. This brain cell line demonstrated notably high transfection efficiency with pcDNA3-EGFP plasmid using Lipofectamine 3000 transfection reagent. This continuous cell line presents a valuable in vitro tool for diverse research applications, including gene transfer and expression studies.

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Successful captive seed production of the recently identified sparid, Sparidentex jamalensis, is a significant achievement for its farming and conservation. In each breeding attempt, a male with oozing milt was paired with a female freshly implanted with an LHRH-a pellet (100 μg LHRH Kg−1 of fish). Oocyte diameter of the selected female was ranging from 420 to 470 μm. The pair was maintained in a rectangular fibre reinforced plastic (FRP) tank (3000 L) adequately aerated from a single point aeration. Over three consecutive days, the fish spawned in batches, commencing from 42 h after pellet implantation. The daily spawning fraction of this multiple spawner ranged from 0.179 to 1.123 million per female. Among 18 attempts, successful spawnings were observed in 12 (66.7%) instances. Fertilisation rates ranged between 82 and 88%, with hatching percentages varying from 76 to 84%. The embryonic developmental phase spanned 17 to 22 h. At the pre-flexion stage [13 days post hatch (dph)], larvae measured up to 4.2 ± 0.18 mm, with notochord flexion initiating on 15 dph (8.45 ± 1.2 mm), accompanied by marked development in dorsal, anal, and caudal fins. Completion of fin ray formation and initiation of scale and lateral line development commenced on 30 dph (21.1 ± 0.3 mm) indicating the metamorphosis of larvae to juveniles. By 40 dph (28.46 ± 3.8 mm), the advance juvenile displayed fully formed fins, silvery scales and a distinct lateral line. Rapid developments in total length, body girth, mouth opening, and eye diameter were particularly noticeable as flexion development neared completion (15 dph). During larval rearing, three critical phases were observed: the period from mouth opening to first feeding (3 to 5 dph), the weaning period (25 to 30 dph), and the metamorphosis phase (35 to 40 dph), each exhibiting distinct mortality patterns. Initial swim bladder inflation was observed before 13 dph (4.2 ± 0.18 mm). Co-feeding copepod nauplii and rotifer (3 numbers mL−1 each) emerged as the ideal feeding strategy during the initial phase, significantly enhancing survival rates. The final larval survival at the end of metamorphosis on 40 dph ranged between 3.8 and 6.2%. Notably, natural light exposure, with a diurnal variation from 1000 to 4000 lx near the water surface, played a pivotal role in improving the initial larval survival.

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This study was conducted to map the marketing channels and price ranges of some commercially important marine finfish species in two coastal districts of West Bengal. Nine commercially important marine finfish species were investigated. Different nodes were found to be involved in the marketing channel depending on the commercial value of the species, and a large gap was observed between the price in the retail market and the price received by the primary fisher. A large number of stakeholders are involved and find employment in the fish marketing chain as fishers, assemblers, processors, traders, wholesalers, retailers, transporters and loading and unloading workers. The price range of Bombay duck (Harpadon nephereus) was Rs. 25-50/kg at the auction centre level to Rs. 300-500/kg at the level of retailers in distant markets. For Silver pomfret (Pampus griseus), the price range had large fluctuations with Rs. 150-1000/kg at the auction centre level itself. When the commodity reaches the retailers in the distant markets, the price range was Rs. 350 to 1300/kg. The marketing chain for the flow of Orange-spotted grouper (Epinephelus coioides) was narrow with the nodes such as commission agents, assemblers, wholesalers and retailers, who play a major role in distributing the landings from the auction centre to domestic consumers. Processing and export nodes were not to be found. The price range was Rs. 200- 300/kg at the auction centre level to Rs. 400-500/kg at the retailer level in distant markets. The investigation exposed the range of actors required to bring the product from the landing centre through the different phases of distribution and delivery to final consumers. The value chain approach will be useful for the key actors such as fishers, managers and policymakers to streamline their operations cost-effectively, for increased earnings of the value chain actors and notable impacts on credit repayment.

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Asian seabass (Lates calcarifer), an important species for mariculture in the Asia-Pacific region, has been threatened by various infectious diseases hampering the profitability of its aquaculture. Vibriosis is the most common disease leading to considerable mortality and economic loss. Recent studies revealed that Vibrio alginolyticus is one of the most common species that causes vibriosis in farmed aquatic animals, including L. calcarifer. Despite our understanding of the aetiology, there is little information on the subsequent histological changes following experimental infection in fish. The present study fills this gap by investigating the sequential histopathological alterations in Asian seabass post intraperitoneal injection with V. alginolyticus. Significant organ changes were seen in the spleen, kidneys, liver, and to a lesser extent, the gills. The findings revealed an initial latency before major tissue responses occurred, with the kidney exhibiting the earliest and most severe changes. The spleen and liver also showed substantial alterations, while the gills showed minor changes. Experimental V. alginolyticus infection resulted in 90-95% mortality within 24-48 hours post-challenge. Our findings contribute to a more thorough understanding of histological changes in Asian seabass during V. alginolyticus infection, highlighting the importance of disease progression, and mitigation measures.

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The Arabian Sea middle-sized form (ASM) of the purpleback flying squid, Sthenoteuthis oualaniensis differs genetically from the other three morphotypes of the species from this region. Statolith microstructure analysis was used to investigate the age and growth of typical ASM squid. The number of increments in the statolith of the ASM form ranged from 38 to 156 which, assuming a daily periodicity of increment deposition, equates to a short lifespan. The growth rate varied between 0.12 and 2.1?mm of dorsal mantle length (DML) per day. Age-DML and age-body-weight data were best fitted with linear and power models respectively. The paralarval phase of S. oualaniensis in the Arabian Sea was about two months. Sthenoteuthis oualaniensis matured rapidly, some within 100 days. Median age at first maturity was 115 days at a size of 115?mm for males and 118 days at a size of 156?mm for females. The back-calculation of hatching dates of the ASM form indicated that spawning takes place throughout the year with a peak in November. The ASM form in the southern Arabian Sea may be an early maturing group, while squids in the Northwest Indian Ocean may be a late maturing group

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