Seafood Waste Management Status in Bangladesh and Potential for Silage Production

Investigating the impact of oligo-chitosan on the growth dynamics and yield traits of Oryza sativa L. 'BRRI dhan29' under subtropical conditions

Reducing the harmful chemical use along with obtaining potential yield in field is a worth exploring practice in rice cultivation. To mitigate the prevailing yield gap, the current study was designed to evaluate the effect of chitosan in improving growth, yield contributing characters and yield of rice. The experiment comprised eight different treatments viz. control (no fertilizer and Chitosan) (T0), conventional method (with fertilizers) (T1), conventional method with foliar spray of 100 ppm chitosan solution (T2), conventional method with foliar spray of 300 ppm chitosan solution (T3), conventional method with foliar spray of 500 ppm chitosan solution (T4), only foliar spray of 100 ppm chitosan solution (T5), only foliar spray of 300 ppm chitosan solution (T6), and only foliar spray of 500 ppm chitosan solution (T7). The experiment was laid out in a completely randomized block design containing three replications. Data on different vegetative and yield contributing characters were recorded to evaluate the treatments effectiveness in improving rice yield. Different growth and yield contributing characters showed significant improvement after applying chitosan in addition to the conventional production system. The conventional method with foliar spray of 500 ppm chitosan solution had a greater positive effect on yield contributing characters and yield. In vegetative characters, the highest plant height became (87.3 cm), number of tiller hill-1 (13.7), Total dry matter (12.9), leaf area index (1.35), and chlorophyll content (57.73). On the basis of assessed treatments in yield contributing characters and yield, the highest plant height was (91.8 cm), no. of grains panicle-1 (145.29), grain yield (6.37 t ha-1), straw yield (6.47 t ha-1). Results showed that the conventional method with foliar spray of different concentration of chitosan solution was able to increase yield up to 26 % in comparison to the conventional method. Overall, our findings suggest that additional foliar spray of chitosan with previously recommended cultivation practice can increase the yield per unit area and offers promising technology to achieve potential yield in farmer's field.

Valorization and repurposing of seafood waste to next-generation carbon nanofertilizers

The surge in population growth, urbanization, and shifts in food consumption patterns have resulted in a rise in the global production of organic waste. This waste material must be repurposed and effectively managed to minimize environmental footprints. The generation of abundant biowaste, especially from marine sources, may have detrimental impacts on the environment and human health if left untreated. In recent years, substantial efforts have been made to valorize seafood waste, contributing significantly to the sustainability of the blue economy through the repurposing of marine discards. Seafood waste can be transformed into different by-products which can be applied as soil amendment to enhance soil quality and health, demonstrating a holistic approach to repurposing and waste utilization. The extraction of bioactive metabolites from these waste materials has opened avenues for developing nanofertilizers. This intersection of waste valorization and nanotechnology is pertinent in the context of sustainable agriculture. While conventional fertilizers improve soil fertility with significant leaching and gaseous losses, the advent of nanofertilizers introduces a paradigm shift with their targeted and controlled delivery mechanisms, rendering them significantly more efficient in resource utilization and mitigation of environmental crises. This review delves into the global issue of seafood waste accumulation, offering an overview of various methods for repurposing. The primary aim of this review is to bring into limelight the recent efforts in developing a portfolio of carbon-based nanofertilizers derived from organic waste, replacing previous valorization methods due to their sustainability, efficiency, and eco-friendliness. There are immense opportunities for future work in this direction by exploring innovative nanoengineering approach owing to the potential of carbon nanofertilizers in enhancing the production of value-added products and reduction of environmental pollution.

Characterization of hatchery residues for on farm implementation of circular waste management practices

The conventional management of hatchery residues is associated with greenhouse gas and unpleasant odor emissions, the presence of pathogens and high disposal costs for producers. To address these issues, on-farm alternatives like composting, fermentation, and insect valorization are promising approaches. This study aims to characterize hatchery residues and define critical quality thresholds to identify effective processes for their management. Hatchery residue samples were collected bi-monthly over a year (N = 24) and were analyzed for proximate composition (dry matter, ash, energy, crude protein, crude lipid, crude fiber, carbohydrates), pH, color (L*a*b*, Chroma) and microbiological loads (total aerobic mesophilic counts, coliforms, lactic acid bacteria). Volatile fatty acid composition was also measured (N = 8). Significant correlation coefficients were found between TAM and LAB loads and residue characterization (pH, chroma, crude fibers, carbohydrates, and temperature). On a dry matter basis, residues were high in energy (2498 to 5911 cal/g), proteins (21.3 to 49.4 %) and lipids (14.6 to 29.1 %), but low in carbohydrates (0 to 15.3 %) despite temporal fluctuations. Ash content varied widely (8.6 to 49.1 %, dry matter) and is influenced by eggshell content. Microbiological loads were high for total aerobic mesophilic bacteria (6.5 to 9.1 log cfu/g), coliforms (5.4 to 8.5 log cfu/g) and lactic acid bacteria (6.7 to 9.0 log cfu/g). Valorization of hatchery residues on the farm will depends on the optimization of effective upstream stabilization processes. The critical points are discussed according to the valorization potentials that could be implemented on the farm from composting to upcycling by insects.

Understanding fish waste management using bibliometric analysis: A supply chain perspective

Food loss and waste have become an issue of global significance, considering their concurrent effects on the socioeconomic and environmental facet of society. Despite this domain gaining prolific attention recently, issues hampering the effective utilization of residues from fish processing usually go unidentified in developing economies such as India. This occurs mainly owing to fragmented supply chains, inappropriate handling, discontinuous cold chains, inadequate temperature monitoring and so on, affecting quality and causing underuse. Any researcher trying to understand the prospects of utilizing these fish processing co-streams in a developing economy with the vision of improving consumption, economic sustainability, reducing discards and promoting circularity faces a lacuna. The authors address this demand in research by identifying the validity of this domain both in the global and native research community by conducting a detailed review using bibliometric analysis and content analysis. Data from Scopus with 717 documents, comprising 612 research articles from 78 countries, 1597 organizations and 2587 authors, are analysed. Results signify (i) developing a focus on hydroxyapatite production, bio-methane generation, transesterification processes, biomass and the rest raw material generated from fish processing, and (ii) reduced research on supply chain-related aspects despite their considerable importance. To comprehend this deficiency, especially in the Indian stance, barriers hindering the utilization of generated by-products are identified, and recommendations for improvements are proposed. The results will provide the struts for a circular and sustainable supply chain for processed seafood in developing economies.

Sustainable Utilization of Fishery Waste in Bangladesh—A Qualitative Study for a Circular Bioeconomy Initiative

Living marine resources are limited; therefore, utilizing them sustainably is essential. Not all resources obtained from the sea are used adequately, causing discards, on-board waste, and by-products and waste on land. Recognition of the limited marine resources and increasing environmental pollution has emphasized the need for better utilization of by-products. Waste may include particles of flesh, skin, bones, entrails, shells or liquid stick water. Unfortunately, no fishery waste and by-product management initiatives or projects exist in Bangladesh; by-products are generally thrown into dustbins, ponds, rivers, and the sea. Bangladesh’s fish-processing waste and fishery by-products could be exported, providing a source of foreign currency earnings. Primary and secondary data were collected through documentary analysis, a literature review, and in-depth interviews (n = 129) with fishers and other relevant stakeholders regarding the challenges of Bangladesh’s sustainable fishery by-products and fish-processing waste. The data were analyzed thematically, guided by the most meaningful stories, and show that fish waste, or fishery by-products, should not be considered less valuable than the fish itself but is a precious and profitable resource capable of bringing health, social, economic, and environmental benefits. Our results reveal that fishery waste can expand local communities’, especially fishers’ and other workers’, potential for jobs or alternative income-generating tasks during fishing ban seasons. Finally, suggestions for managing fishery waste and fishery by-products are made to ensure improved and sustainable utilization via a circular bioeconomy.