Department of Fisheries

Fish processing waste represents a significant, underutilized biomass resource, with global annual production typically estimated at 50–130 million tonnes. Current disposal methods, such as landfilling and ocean dumping, contribute to eutrophication, nutrient enrichment, and climate change. Additionally, food system assessments indicate that waste accounts for approximately 8% of greenhouse gas emissions. This review consolidates existing evidence on the zero-waste valorisation of fish byproducts within circular bioeconomy frameworks, analysing technological feasibility, environmental performance, and regulatory constraints. The analysis investigates significant side streams, including scales, skin, bones, viscera, heads, oils, swim bladders, crustacean exoskeletons, fins, and livers, focusing on compositional variability and its implications for process design. The evaluation of key extraction and conversion routes includes enzymatic hydrolysis, ultrasound-assisted processing, microwave-assisted processing, supercritical fluid extraction, and pulsed electric field treatment, with an emphasis on recovery yield, functional quality, and energy intensity. Integrated biorefinery configurations achieve over 70% resource recovery and reduce greenhouse gas emissions by 50–75% compared to disposal. However, outcomes depend on feedstock logistics, stabilization, and the integration of unit operations. Persistent barriers encompass sanitary compliance, cross-batch standardization, contaminant surveillance and removal, and substantial capital requirements, which disproportionately hinder operators in small-scale and developing countries. Research priorities encompass techno-economic assessment, life-cycle impact quantification, regulatory harmonization, and quality specifications, as well as policy implements that mitigate investment risks and expedite deployment.

Tomato ( Lycopersicon esculentum Mill.) trading plays a vital role in supporting rural livelihoods and contributing to household food security. This study examined the socioeconomic opportunities and challenges faced by tomato traders in the district. Primary data were collected through semi-structured questionnaires administered to traders, and descriptive and inferential statistics were used to analyse the data. The majority of traders were women (77.5%), predominantly aged between 20 and 30 years, and more than half (57.5%) had attained primary education. Women were found to be earning more on average than men through tomato trading. Income generation was the primary motivation for engaging in tomato trading (45%), with most traders (70%) relying on personal savings as their main source of start-up capital. The main opportunities identified were high consumer demand (35.4%) and access to new markets (29.2%), whereas poor market infrastructure (28.8%) and high transportation costs (21.2%) were the major challenges. Traders highlighted the need for financial support (53.3%) and improved infrastructure (33.3%) to enhance operations. The results indicated a statistically significant association between education level and weekly income ( χ 2 (6) = 37.638, p < 0.001). Similarly, a statistically significant association was observed between gender and weekly income ( χ 2 (3) = 22.456, p < 0.001). Given that tomato traders are predominantly young women with low levels of formal education, the findings suggest that access to credit and vocational capacity-building interventions should be specifically targeted at young and female traders to improve incomes and enhance the sustainability of tomato trading in rural Zambia.

Simple prediction of food composition and related properties could reduce reliance on complicated measurement methods that use costly instruments and chemicals. In this study, low-field nuclear magnetic resonance (LF-NMR) relaxation measurements (T1 and T2) were used. Nine batches of date fruits (DFs) differing in quality were analyzed using relaxation descriptors extracted to characterize proton environments associated with different mobility states, with transverse (T₂) relaxation reflecting contributions from rigid, semirigid, and mobile proton populations. Descriptors associated with rigid, semirigid, and mobile proton populations were obtained using transverse (T2) relaxation. The relationships between these parameters and the physicochemical characteristics of the samples of date fruit were analyzed. LF-NMR T1 and T2 parameters showed linear correlations with studied physicochemical properties, including moisture, crude fiber, and pectin. This indicates the potential of LF-NMR for predicting physicochemical properties of date fruits. Multivariate analysis was used to examine clustering trends among date fruits based on LF-NMR relaxation behaviors. The decision tree model achieved high predictive performance for moisture content (R2 = 0.990) using T₂ relaxation parameters. Artificial neural networks considering T2 relaxation also showed strong internal predictive performance for sucrose (R2 = 0.998) and fiber (R2 = 1.000). These results demonstrate that integrating LF-NMR relaxation with multivariate and machine learning approaches provides an effective framework for predicting key physicochemical attributes of date fruits.

Abstract Density-dependent mortality is a key mechanism regulating fish population dynamics, yet empirical evidence from tropical systems remains limited. This study investigated density-dependent survival during early life stages of 25 dominant taxa from trawl landings in the Gulf of Thailand, a productive tropical system dominated by multispecies and multi-gear fisheries, where trash fish (TF) catches from trawlers comprise proportions of juveniles. Temporal variation in the abundance of fish at ages smaller than L 25 was linked to subsequent survival patterns to evaluate compensatory dynamics. Growth parameters revealed wide interspecific variation in life-history strategies, ranging from fast-growing ( Encrasicholina spp.) to a slower-growing demersal group (Sciaenidae). Most taxa exhibited a negative density– survival relationship, with 11 taxa (including Rastrelliger kanagurta, Atule mate , and Lutjanus lutjanus ) showing strong and significant compensatory density dependence ( p < 0.001), indicating elevated mortality at higher juvenile densities. Evidence for depensatory dynamics was weak and statistically unsupported. These results provide empirical biological evidence that compensatory density-dependent mortality commonly operates during early life stages in tropical multispecies and multi-gear fisheries. The findings suggest that juvenile removal via TF catches does not uniformly translate into reduced long-term productivity, highlighting the importance of incorporating early-life density dependence into stock assessment and management frameworks.

The study was conducted from August–September, 2024 at the Fish Seed Production Center and Fish Farm of the College of Fisheries Science, Nagpur, Maharashtra, India to systematically evaluate metabolic and stress-related responses of Labeo catla fingerlings under varying stocking densities to determine and standardize the optimal conditioning density that minimizes stress, reduces mortality, and enhances post-transport efficiency. In this study, Catla fingerlings (90.82±5.91 mm) were conditioned in a flow-through system with a water exchange rate of 6.5 l min-1 for the period of 24 h, during this, fingerlings were stocked at four densities: 1 fingerling l-1, 2 fingerlings l-1, 3 fingerlings l-1, and 4 fingerlings l-1. During conditioning, blood samples were collected for glucose, lactate, hemoglobin, and hematocrit estimation, while muscle samples were used for glycogen analysis following anesthesia with clove oil and humane euthanasia. Water quality parameters such as dissolved oxygen and total ammonia nitrogen were monitored to assess metabolic load under varying densities. The results showed density-dependent stress responses. 4 fingerlings l-1 exhibited significantly higher blood glucose and lactate, lower glycogen levels, and greater mortality (p<0.05), indicating elevated stress. While water quality remained stable overall, 4 fingerlings l-1 showed more DO depletion and total ammonia buildup. 3 fingerlings l-1 showed the best balance between stocking pressure and physiological stability, indicating it was the optimal conditioning density for Catla fingerlings in flow-through systems.

The Totok and Makalo River estuaries in North Sulawesi, Indonesia, serve as vital habitats teeming with fish biodiversity, supporting coastal ecosystems and local fisheries. This study aimed to identify fish species and elucidate their genetic relationships through DNA barcoding of the Cytochrome Oxidase I (COI) gene. Fish samples were collected from both estuaries using nets and traps, followed by molecular analysis involving polymerase chain reaction (PCR) amplification and Sanger sequencing. The results confirmed the presence of 11 fish species, including Osteomugil engeli, Polydactylus plebeius, and Gazza minuta, with high identification accuracy (over 98% sequence similarity to reference databases). Notably, Paracentropogon rubripinnis and Nematalosa come were recorded for the first time in North Sulawesi waters, expanding the known distribution of these species. Significant genetic variation was detected in P. rubripinnis, potentially indicating cryptic speciation or local adaptation to environmental gradients. Phylogenetic analysis revealed close genetic affinities between certain species and populations from Taiwan and Bangladesh, suggesting historical migration patterns or shared ancestry, possibly facilitated by ocean currents. These findings underscore the rich genetic diversity in these estuaries, which are influenced by factors like salinity, temperature, and anthropogenic pressures. The study emphasizes the urgency of conservation strategies, including habitat protection and sustainable fishing practices, to preserve biodiversity and maintain ecosystem services. By providing baseline data on species composition and genetic connectivity, this research contributes to broader efforts in marine biodiversity monitoring and informs policy for coastal management in Indonesia's biodiversity hotspots.

Abstract Growing in popularity as the demand for sustainable food production increases is aquaponics, a symbiotic hybrid of hydroponics and aquaculture. Nonetheless, long-term viability depends on effective and environmentally conscious control of pests like weeds, illnesses, and insects. This review highlights new research on the production and application of biopesticides in aquaponics systems, which represents a significant breakthrough in comprehensive pest management. We highlight the limitations of biopesticide use by assessing production processes, providing a comprehensive analysis of the most effective types of biopesticides for a variety of pests, and recommending effective application methods. Our goal is to address significant issues and offer fresh perspectives in order to offer practical guidance to aquaponic practitioners. Eventually, this encourages the development of strong and environmentally conscious aquaponic systems, ensuring comprehensive and efficient pest control while maintaining ecological equilibrium.

A correction refers to a change to their article that the author wishes to publish after publication. The publication of this article is subject to Frontiers' editorial approval.• Please read through all the templates before choosing • Pick the most relevant text template(s) from the following page and delete all others.• Edit the text as necessary, ensuring that the original incorrect text is included for the record, please see the below. • Please do not use any extra formatting when editing the templates, and only modify the red text unless absolutely necessary • Submit to Frontiers following the instructions on this page.When the original text contained incorrect information, to preserve the scientific record, please include that text when editing the below templates. For example:There was a mistake in the Funding statement, an incorrect number was used.The correct number is "2015C03Bd051.". The publisher apologizes for this mistake.The original version of this article has been updated.In the published article, there was a mistake in the Funding statement. The funding statement for the Key Development Project of the Department of Science and Technology was displayed as "2015CBd051". The correct statement is "Key Development Project of Department of Science and Technology (2015C03Bd051).''Wrong content There was a mistake in figure [1] as published. Some content in figure1 is missing. The corrected figure[1] appears below.The original version of this article has been updated.Wrong content There was a mistake in figure [9] as published. A black bar appears in Figure 9 that was not created by the authors. The corrected figure [9] appears below.The original version of this article has been updated.Reminder: Figures, tables, and images will be published under a Creative Commons CC-BY license and permission must be obtained for use of copyrighted material from other sources (including re-published/adapted/modified/partial figures and images from the internet). It is the responsibility of the authors to acquire the licenses, to follow any citation instructions requested by third-party rights holders, and cover any supplementary charges.