From ancient times fish has always been considered as an important human food item. The purpose of this article is to introduce the perception that beside consumption, fish can also be used as a raw material for the industrial production of different products. In this article such 19 products have been described. Among them, the conventional fish products described herein include isinglass, pituitary gland, chitin, chitosan, pearl essence, fish skin leather, fish protein hydrolysates and concentrates, fish meal and scrap, fish oil, collagen, gelatin, glue, fish silage, pet food and wet feed from fish, fish fertilizer and compost. These products have important applications in aquaculture, agriculture, food, cosmetics and other industries. Different non-conventional hi-tech fish products has been reported such as novel antimicrobial proteins from skin mucus, enzymes, insulin, protamine, blood proteins, salcotonin, antifreeze proteins, hydroxyapatite, burn treatment bandage, albumins, fishbone calcium powder, biochar, biopolymer, bioplastics, fish industry derived rinse water recovery. These products have many significant applications in chemical, biomedical and pharmaceutical industries. Economical, logistic, environmental and technological considerations from fish waste valorization perspectives has also been presented to evaluate feasibility of industrial-scale production of these products.

Hilsa (Tenualosa ilisha) is the national fish and geographical indication (GI) product of Bangladesh. Salting is the most suitable and oldest method of Hilsa preservation in Bangladesh. The quality of the traditionally salted dried fish in retail markets of Bangladesh is doubtful. This study aimed to assess the organoleptic, nutritional, biochemical, and safety attributes of dry-salted Hilsa. Organoleptic characteristics, nutritional (proximate composition, salt content), biochemical (pH, total volatile basenitrogen (TBV-N), thiobarbituric acid reactive substances (TBARS)), and safety attributes (total plate count, presence of coliform bacteria, Salmonella-Shigella, Staphylococcus, enteropathogenic Vibrio, and heavy metals: Hg, Cd, Cr, Pb, Ni, Cu, Zn) of dry-salted Hilsa was analyzed by standard methods. The product was organoleptically acceptable (defect point score: 2.65). Moisture (48.16%), protein (29.95%), lipid (4.36%), ash (17.53%), and salt (17.90%) content showed that the product was highly nutritious for human consumption. The pH, TVB-N, and TBARS values were 6.21, 83.25 mg N/100 g, and 4.18 mg MDA/Kg, respectively. Total plate count, coliform, Staphylococcus bacteria were 7.87×104 , 6.96×103 , and 2.70×103 CFU/g, respectively, indicating that the microbiological quality of the product was not satisfactory. However, Salmonella-Shigella and Enteropathogenic Vibrio were not found in the samples. Amounts of Hg, Cd, Cr, Pb, Ni, Cu, and Zn were 0.00005, 0.00004, 0.00112, 0.00102, 0.00134, 0.00167, and 0.00045 µg/g, respectively; which were within safety limit for human consumption. To improve the quality of dry-salted Hilsa, processors, sellers, and other stakeholders should be trained up properly.

Nutritional constituents and bacterial community of hilsa (Tenualosa ilisha) at different stages of dry salt-fermentation; namely, F1 (after 2 days of salting), F2 (after 5 days of salting) and F3 (ripe product after 15 days of salting) was studied. Dry salt-fermentation did not negatively affect proximate biochemical composition. Total protein content in F1, F2 and F3 was 10.14, 22.30 and 16.21 mg/ml, respectively. With progression of ripening process, protein solubility gradually decreased. In all stages, about 98% protein digestibility was found. TBARS (Thiobarbituric acid reactive substances) values at F1, F2 and F3 stages was 0.30, 0.41 and 0.95 mg MDA/kg, respectively and within acceptable limit. A total of 3,248 OTUs were found. Of the identified 48 phyla, Proteobacteria (66%), Firmicutes (18%) and Bacteroidota (11%) were abundant at F1 stage but Firmicutes (82%) and Proteobacteria (9%) were dominant at F3 stage. Significant differences in the microbial β-diversity among initial, interim and ripe product were observed. There was no significant α-diversity difference at individual stages of dry salt-fermentation of hilsa. Functional gene profile revealed that, in the final product microbial genes related to organismal systems replaced human disease related genes found in initial and interim product. These findings provide new clues for in-depth characterization of salt-fermented foods from viewpoint of food chemistry and microbiology. Graphical Abstract

Rapid global population growth depleting finite terrestrial resources which are directed towards sustainable utilization of the oceans. The blue economy is a macro-economy concept where eco-friendly innovations are applied for the sustainable production of marine goods and services for social solvency. In this paper, the global blue economy definition, blue economy potentials, resources, blue economy in fisheries and aquaculture sector, present shrimp cultivation status and blue economy of shrimp cultivation from Bangladesh perspectives have been reviewed. Potential blue economy sectors in Bangladesh are mariculture, deep sea fishing, biotechnology, marine energy, submarine cable connections, etc. Blue economy resources are biological resources, government agencies, human resources, ports-harbors, vessels and submarines, in addition to remote sensing facilities. To embrace the blue economy, fisheries and aquaculture should include technologies, such as big data analysis, machine learning, artificial intelligence and precision aquaculture. Shrimp cultivation occurs in Khulna, Chittagong, Cox’s Bazar, and Bhola regions mostly by traditional methods. Shrimp pond management, cultural practices, harvesting, grading, production, supply, and future potential has been addressed. Shrimp production is increasing steadily. The blue economy of shrimp culture involves innovative solutions to settle down unsustainability issues. A conceptual framework addressing major challenges and sustainable interventions has also been reported. Recommendations are directed to consider government policy declaration, public awareness, coordination among state agencies, establishing a national marine data hub, supporting research and development, and employing more manpower, as well as regional and international collaborations.