Efficacy of sodium bicarbonate (Baking soda) and clove powder (Syzygium aromaticum) as anaesthetic agents for Nile tilapia (Oreochromis niloticus, linnaeus 1758) juveniles

Anaesthetics in aquaculture serve as a stress avoidance mechanism, mitigating stress-related impacts during fish handling and transportation. This study assessed the efficacy of sodium bicarbonate and clove stem powder as anaesthetic agents for Nile Tilapia juveniles. Four hundred and twenty uniform O. niloticus juveniles (5 ± 0.5 g, 74 ± 5 mm) were exposed to varying concentrations of sodium bicarbonate (10, 15, 20, 25, 30, 35, 40 g/L) and clove stem powder (0, 1, 3, 5, 7, 10, 15 g/L) in 20 L transparent plastic tanks. The results showed an inverse relationship between anaesthetic concentration and induction time, a direct relationship with recovery time, and an inverse correlation between induction and recovery times for both agents (P < 0.001). The Appropriate concentrations were determined as 25 g/L for sodium bicarbonate and 10 g/L for clove stem powder. At these levels, induction and recovery times met ideal criteria (3-5 min induction, 5-10 min recovery), with fish exhibiting normal behavior and 100% survival after a week of monitoring

Sustainability of agriculture extension services in the face of COVID-19: a study on gender-specific market systems

In the fourth industrial revolution, achieving sustainable agricultural development while feeding a growing world population and maintaining a balanced interrelationship between the economy, society, and the environment has been a significant challenge. However, COVID-19 disrupted agricultural extension and advisory systems, affecting all market participants. The complexity of the pandemic has impacted the private sector, public sector, extension staff, donor funding, education, and research systems, subsequently affecting human nutrition. This paper aims to expertly review COVID-19’s effects on the sustainability of gender-specific agricultural extension service systems. Demand and supply market stakeholders in the extension system are thematically discussed. The findings reveal various consequences of COVID-19 for market actors on both the demand and supply sides of the extension system. Private-sector players often support expansion directly or indirectly, with multi-sectorial support and funding strategies existing for sustainability. In many developing nations, the comprehensive extension system was disrupted by COVID-19, impacting household incomes and nutrition. The pandemic accelerated the adoption of digital technologies in many developing nations, transitioning from a centralized to a decentralized and pluralistic extension model. Multi-sector coordination and execution, especially from health and other sectors, are crucial in managing complex crises that disrupt the market system

Application of anaesthetics in fish hatcheries to promote broodstock and fish seed welfare in Zambia

AbstractThis study investigated the application of anaesthetics in 23 private and government-owned hatcheries in 10 provinces of Zambia. The study employed both qualitative and quantitative research designs and used a structured questionnaire to collect data from the respondents. The results showed that most hatcheries (65%) were not using anaesthetics in handling fish and all (100%) that were using anaesthetics (35%) used clove powder as the only type. Most respondents (61%) were not sure or did not have information about the availability of the anaesthetic substances in their localities while only 26% reported wider availability but 13% had a divergent claim. The mortality rate for fingerlings in hatcheries that applied anaesthetics ranged between 15–30% with consistently high demand while those that did not use anaesthetics reported mortality rates of more than 50% and had low demand. The majority of the respondents (53%) had received training up to certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority. Furthermore, most respondents (35%) did not know the importance of fish anaesthetics. We conclude that the use of fish anaesthetics in Zambian hatcheries is very low and could partly be the cause of high fingerling mortalities, and there is an urgent need to address the situation

DNA barcoding for the assessment of marine and coastal fish diversity from the Coast of Mozambique.

The ichthyological provinces of Mozambique are understudied hotspots of global fish diversity. In this study, we applied DNA barcoding to identify the composition of the fish fauna from the coast of Mozambique. A total of 143 species belonging to 104 genera, 59 families, and 30 orders were identified. The overall K2P distance of the COI sequences within species ranged from 0.00% to 1.51%, while interspecific distances ranged from 3.64% to 24.49%. Moreover, the study revealed 15 threatened species according to the IUCN Red List of Threatened Species, with elasmobranchs being the most represented group. Additionally, the study also uncovered four new species that were not previously recorded in this geographic area, including Boleophthalmus dussumieri, Maculabatis gerrardi, Hippocampus kelloggi, and Lethrinus miniatus. This study represents the first instance of utilizing molecular references to explore the fish fauna along the Mozambican coast. Our results indicate that DNA barcoding is a dependable technique for the identification and delineation of fish species in the waters of Mozambique. The DNA barcoding library established in this research will be an invaluable asset for advancing the understanding of fish diversity and guiding future conservation initiatives

Comparative mitochondrial genome brings insights to slight variation in gene proportion and large intergenic spacer and phylogenetic relationship of mudskipper species

Abstract Fish mitochondrial genome have been largely studied worldwide for evolutionary and other genetic purposes and the structure and gene organization are commonly conservative. However, several studies have demonstrated that this scenario may present variations in some taxa, showing differentiation on the gene rearrangement. In this study, the complete mitogenome of terrestrial fish Boleophthalmus dussumieri was generated and compared with other species of the Exudercidae fishes. The newly complete mitogenome generated is circular and 16,685 bp of length, and it contained 13 protein-coding genes (PCGs), two ribosomal RNA (rRNAs), 22 transfer RNA genes (tRNAs), and one control region (CR), with high conservative structure, like other Mudskippers. Most of the PCG showed similar codon usage bias. The gene length was found to be different specially for the CR, 12S rRNA gene and ND5 gene in some taxon. All the Boleophthalmus species showed a gene duplication in the CR, except for B. dussumieri, and they presented a long intergenic spacer specially on the tRNA-Pro/ OH Tandem duplication/random loss (TDRL) and dimer-mitogenome and nonrandom loss (DMNL) are suitable to explain the mitogenome rearrangement observed in this study. The phylogenetic analysis well supported the monophyly of all mudskipper species and the analysis positioned the Periophthalmus clade as the most basal of the terrestrial fishes. This finding provides basis and brings insights for gene variation, gene rearrangements and replications showing evidence for variety of mitochondrial structure diversity within mudskippers

Sustainability of agriculture extension services in the face of COVID-19: A study on gender-specific market systems

In the fourth industrial revolution, achieving sustainable agricultural development while feeding a growing world population and maintaining a balanced interrelationship between the economy, society, and the environment has been a significant challenge. However, COVID-19 disrupted agricultural extension and advisory systems, affecting all market participants. The complexity of the pandemic has impacted the private sector, public sector, extension staff, donor funding, education, and research systems, subsequently affecting human nutrition. This paper aims to expertly review COVID-19’s effects on the sustainability of gender-specific agricultural extension service systems. Demand and supply market stakeholders in the extension system are thematically discussed. The findings reveal various consequences of COVID-19 for market actors on both the demand and supply sides of the extension system. Private-sector players often support expansion directly or indirectly, with multi-sectorial support and funding strategies existing for sustainability. In many developing nations, the comprehensive extension system was disrupted by COVID-19, impacting household incomes and nutrition. The pandemic accelerated the adoption of digital technologies in many developing nations, transitioning from a centralized to a decentralized and pluralistic extension model. Multi-sector coordination and execution, especially from health and other sectors, are crucial in managing complex crises that disrupt the market system.</p