Aquaculture
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12348/2
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- Aeromonas veronii biotype sobria is a potential aquatic zoonotic pathogen and a major cause of freshwater bacterial infections in cultured fish globally, leading to substantial economic losses. This study aimed to establish the median lethal dose (LD50-96 h) for Aeromonas veronii biovar sobria A4 strain and to demonstrate induction of clinical signs, gross and microscopic lesions in experimentally infected juvenile Nile tilapia (Oreochromis niloticus). Aeromonas veronii biotype sobria A4 strain used in this study were obtained from water samples from ponds with high fish mortality at Cavarino farm in Narok County, Kenya. Six groups each comprising 10 fish were intraperitoneally injected with 0.1 mL of A. veronii biovar sobria A4 strain suspension at: 1.5 × 104, 1.5 × 105, 1.5 × 106, 1.5 × 107, 1.5 × 108, and 1.5 × 109 colony forming units per mL (CFU/mL) respectively and the bacteria was afterward recovered from kidney and hepatopancreas of freshly dead fish. Duplicate control groups (each n = 10) were injected with sterile physiological saline before the lethal dose group were injected with varying concentration of the A. veronii biovar sobria A4 strain. The LD50-96 h of A. veronii biovar sobria A4 strain was found to be 1.5 × 108 CFU/mL. Clinical signs and gross lesions observed in the lethal dose group were: skin hemorrhages (20%), erosion of the fins including caudal fin with scale loss exposing underlying skin (13.7%), congested and hemorrhagic gills (15%), hepatic hemorrhages and enlargement (21.3%), distension of gall bladder (18.8%), splenomegaly and congestion (22.5%), and ascites (16.3%). The main histopathological lesions observed in the gills were focal hemorrhages, atrophy of the filaments and loss of lamellae in some filaments with mononuclear cellular infiltration; on the liver there were; hemorrhages, infiltration with lymphocytes and melanomacrophages, degenerative hepatocytes and focal necrosis. There was extensive hemosiderosis with increased melanomacrophages in the spleen. The kidney showed extensive hemorrhages, localized coagulative necrosis, atrophied glomeruli and multifocal mononuclear cellular infiltration in the interstitium. The findings will lay a foundational basis for subsequent investigations into the host-pathogen interaction, therapeutic approaches, and epidemiology of Aeromonas veronii biovar sobria.
- Parasitic infections threaten the endangered Oreochromis jipe and other ichthyic populations in Lake Jipe, thereby hindering conservation efforts. Initiatives have been made to farm O. jipe as a conservation strategy. To develop effective conservation approaches and ensure the species' survival in its natural habitat and aquaculture systems, it is imperative to understand the diverse parasites in these habitats. Consequently, this cross-sectional study was conducted to determine parasitic loads in tilapias from selected farms and Lake Jipe. A total of 111 fishes were collected (76 farmed, 35 from the lake), comprising 66 O. jipe, 34 Oreochromis niloticus and 11 hybrids of O. jipe and O. niloticus. The fish were euthanized, necropsied and examined for parasitic infections via visual inspection and light microscopy. Out of 111 fishes examined, 58 (52.3%) were infected with 212 parasites, including 135 (63.7%) and 77 (36.3%) from farm and lake habitats, respectively. The prevalence of parasitic infections in fish from the lake and farm habitats was 68.6% and 44.7%, respectively. The most frequently occurring parasite genera identified were Diplostomum (30.63%), Acanthocephalus (20.7%), Dactylogyrus (9.9%) and Contracaecum (2.7%), with mean intensities of 2.9, 3.7, 1.9 and 1.7, respectively. Contracaecum and Camallanus were exclusively found in fish from Lake Jipe, while Euclinostomum and Gyrodactylus were only observed in farmed fish. O. jipe had the highest prevalence of parasitic infections (59.1%), followed by O. niloticus (44.1%) and hybrids (36.4%) (p > 0.05). In conclusion, the examined fishes were infected with diverse parasites, which have both public health concerns (Euclinostomum and Acanthocephalus) and economic significance (Dactylogyrus and Gyrodactylus). Consequently, it is imperative to enhance public awareness and enforce biosecurity measures to mitigate potential health risks and to improve the productivity of the pond culture system and lake ecosystem. These measures will help reduce parasite dissemination and promote sustainable fish production and populations.
- Aquaculture plays a vital role in enhancing food security in Africa but faces challenges in the fed aquaculture sector, particularly in accessing and producing high-quality aquafeeds. To address this, FAO organized the “Expert Workshop on Local Alternative Ingredients, Aquafeed Supply, and Feeding Management” in Egypt in 2023. Experts and stakeholders from nine African countries—Cameroon, Egypt, Ghana, Kenya, Malawi, Nigeria, Uganda, the United Republic of Tanzania and Zambia—participated, alongside representatives from governments, academia, development agencies, the private sector, and farming communities. Pre-workshop questionnaires informed national reports on feed ingredient supply, feed manufacturing, and feeding management practices. These reports, along with workshop discussions, form the basis of this technical document comprising nine country analyses and a regional synthesis. Common challenges identified include limited access to alternative feed ingredients, poor feed preparation and storage practices, inadequate monitoring of on-farm feeding, lack of investment for small-scale producers, low technical capacity among farmers, poor feed quality, and weak regulatory frameworks. The synthesis report recommends key actions: stabilizing feed ingredient supply and costs, promoting training for feed producers and farmers, improving on-farm feed and water quality management, enhancing data collection and analysis, expanding access to finance and storage facilities, and strengthening collaboration among stakeholders. These measures aim to build a more efficient, sustainable, and resilient aquaculture sector across the region.
- The Clostridium autoethanogenum-derived protein (CAP) is a microbial protein generated during ethanol fermentation of agricultural byproducts. The present investigation evaluated the use of CAP as a sustainable alternative to reduce fishmeal (FM) dependency in aqua-feeds. A 70-day feeding trial was done to examine the impacts of partially replacing FM protein by CAP at 0 % (control, CAP0), 10 % (CAP10), 20 % (CAP20), 30 % (CAP30), and 50 % (CAP50) inclusion levels in diets for European seabass (Dicentrarchus labrax) juvenile (initial weight 10.5 ± 1.5 g). Results obtained demonstrated that dietary CAP incorporation up to 50 % FM replacement did not significantly (P > 0.05) impact the growth performance, feed efficiency, or survival rates. Similarly, the expression levels of growth-related genes (IGF-1 and GH) remained unchanged across treatments. The intestinal digestive enzymes activities, including lipase, alpha-amylase, and proteases, as well as the haematological parameters remained unaffected by the dietary CAP inclusion levels. Histological assessment revealed normal tissue architecture in the intestine, liver, and spleen of fish fed on CAP-containing diets. That indicats no adverse effects of CAP on organs’ structure. A simple economic analysis showed reduced feed costs with increasing CAP inclusion, where production costs per ton of fish gain decreases by 19.3 % at 50 % FM replacement compared to the control diet. These findings establish that CAP is a viable and cost-effective protein source capable of replacing up to 50 % FM protein in practical diets for D. labrax juveniles without compromising their growth, health status, or organs’ structure.
- The Apatani community in Arunachal Pradesh, India has long practiced rice-fish coculture, integrating rice cultivation with fish farming to enhance food security and promote environmental sustainability. This traditional method utilizes the region’s wet rice terraces, allowing for the simultaneous production of rice and fish, contributing to efficient land and water resource utilization. Despite the organic nature of this practice, challenges such as suboptimal input distribution, inappropriate combinations of rice and fish species, and limited access to training have hindered productivity. The overall average yields of 1389 kg/ha for rice and 209 kg/ha for fish, indicating room for improvement. This study focused on optimizing resource utilization and fund allocation among Apatani farmers in Ziro Valley to address these issues. Data were collected from a random sample of 200 farmers across the valley. Using Cobb-Douglas production functions, researchers estimated rice and fish yields through regression models. Subsequently, a non-linear constrained optimization problem based on the Nash-bargaining framework was solved to assess the effects of optimization on fund allocation for various inputs. The findings revealed that rice and fish yields could potentially exceed 2000 kg/ha and 300 kg/ha, respectively, with proper resource management. Critical factors identified for enhancing productivity included using mixed manure and stocking fingerlings. Moreover, improving farmers’ technical knowledge and skills through institutional support and policy interventions was deemed vital for establishing rice-fish coculture as a sustainable livelihood in Ziro Valley. In conclusion, while the Apatani community’s traditional rice-fish coculture system offers a foundation for sustainable agriculture, targeted optimization of resource utilization, combined with enhanced training and institutional support, is essential to realize its full potential in improving productivity and ensuring long-term sustainability.
- Over the past 5 years, WorldFish’s work in Zambia has delivered tangible, measurable change, especially for smallholder farmers, women and youths in rural communities. In the remote provinces of Northern and Luapula, where access to quality fish seed, feed and training is limited, WorldFish introduced practical, inclusive models that have strengthened livelihoods and reshaped local food systems.
- The AABS work package two (WP2) executed the socioeconomic and environmental baseline survey study in Nigeria with the main objective of documenting the coastal aquaculture farmers in Nigeria socioeconomic. This baseline study provides a snapshot of the community's social, economic, environmental, and cultural characteristics, which serves as a reference point to measure changes and impacts resulting from IMTA implementation. In this study we identified key socioeconomic and environmental indicators. These indicators include income levels, education, health, gender dynamics, cultural practices, land ownership, livelihoods, infrastructure and service. Establishing a robust socioeconomic and environmental baseline helps in designing context-specific interventions, predicting potential challenges, and identifying key interventions that could promote the adoption and growth of IMTA in Nigeria.
- Maximizing shrimp yield necessitates the efficient utilization of key inputs to enhance technical efficiency and overall production performance. This study employs Data Envelopment Analysis (DEA) with a double-bootstrap procedure to derive statistically robust efficiency estimates. Using cross-section data of 256 semi-intensive whiteleg shrimp (Litopenaeus vannamei) farms in Tamil Nadu, India, the study shows that most farms operate below the production frontier with an average technical efficiency score of bias-corrected, radial, and non-radial measures equivalent to 0.57, 0.60, and 0.38, respectively. Notable inefficiencies in input utilization underscore the need for targeted interventions to refine resource allocation strategies. The divergence between radial and non-radial efficiency scores suggests that while overall input use is relatively efficient, further optimization in specific resource management practices is required. The determinants of technical efficiency scores are farm size, stocking density, culture duration, and specific growth rate, all exerting statistically significant positive effects on shrimp yield. Findings highlight the critical role of strategic resource allocation to enhance farm performance by improving productivity, which helps ensure the long-term viability of shrimp aquaculture.
- This 6-monthly report covers the activities from October 1, 2023 – March 31, 2024. These activities are related to the four major outputs of the project. The three major thematic outputs are related to increased availability (Output 1), accessibility (Output 2) and consumption (Output 3) of fish; and the fourth output is about knowledge sharing and dissemination (Output 4).
- This report presents the activities of the Partnership for Aquaculture Development in Timor-Leste Phase 2 (PADTL2) from October 1, 2023, to September 30, 2024, focusing on the project's four major outputs: increased availability (Output 1), accessibility (Output 2), and consumption (Output 3) of fish, along with knowledge sharing and dissemination (Output 4).
- This banner outlines the objectives and scope of CAINA project, funded by IDRC and led by WorldFish in collaboration with partner universities and organizations in Malaysia and the Solomon Islands.
- This social media card outlines the objectives and scope of CAINA project, funded by IDRC and led by WorldFish in collaboration with partner universities and organizations in Malaysia and the Solomon Islands.
- This poster outlines the work packages (WP), impact pathways and potential nature-based aquaculture system in Malaysia and Solomon Islands. The project aims to support the transformation of aquaculture into a climate-resilient and inclusive food system through nature-based solutions.
- This poster outlines the impact pathway of the work packages (WP) and potential case study locations in Solomon Islands. The project supports sustainable aquaculture development through nature-based approaches in nascent, small-scale sector.
- This poster outlines the objectives, work packages (WP), impact pathway and potential case study locations in Malaysia. The project aims to support the transformation of aquaculture into a climate-resilient and inclusive food system through nature-based solutions.
- Bacterial diseases can pose a significant challenge to aquaculture in Kenya, leading to significant economic losses. A fish farm in Narok County, Kenya, reported mass mortality among its reared fish which included Nile tilapia, catfish and ornamental fish. This study aimed to characterize an Aeromonas isolate recovered from the farm and assess its potential role in the outbreak. Water samples (n=10) were collected randomly from different points within the fish ponds using sterile universal bottles and transported to the bacteriology laboratory at the Department of Veterinary Pathology, Microbiology and Parasitology, University of Nairobi. The bacterial isolate was identified using conventional culture methods, biochemical assays, Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF), BD Phoenix machine tests, and Whole Genome Sequencing. Based on morphological, biochemical, and MALDI-TOF analyses, the isolate was identified as Aeromonas veronii and further confirmed as Aeromonas veronii biovar Sobria using the BD Phoenix system. The genome size of the isolate was approximately 4.6 Mb with a GC content of 59%. Phylogenetic analysis showed that the isolate clustered with fish isolates from South America and Asia and with human isolates from Asia and Australia. The study underscores the need for more studies on this bacterium’s pathogenicity and development of an autogenous vaccine for the prevention of its bacteriosis.
- This report details the progress made during the 1st quarter of 2025 (January to March), covering the three sub-components of the project.
- The report outlines the achievements of WorldFish and its contributions to the AICCRA Zambia project in 2024. AICCRA stands for Accelerating the Impact of CGIAR Climate Research for Africa. The AICCRA Zambia cluster is led by the International Water Management Institute (IWMI).
- This report presents the results of an assessment of a quarantine facility and three hatcheries in Côte d’Ivoire. The objective of the assessment was to check the readiness of the facility and the hatcheries to receive the Genetically Improved Farmed Tilapia (GIFT) strain of tilapia from WorldFish Malaysia. Two WorldFish scientists traveled to Côte d’Ivoire, where they had an initial consultative meeting with key government stakeholders and interviewed managers at the quarantine facility and the hatcheries. They conducted a practical assessment of the facilities during comprehensive site visits on December 18–23, 2024. The assessment focused on existing infrastructure, biosecurity measures and the technical capabilities necessary to successfully quarantine the soon-to-be-imported GIFT fry and the subsequent nursery, grow-out and multiplication phases required to establish a tilapia breeding program in the country. The quarantine facility and the three hatcheries did meet the minimum requirements. However, they still require a number of important improvements based on the results of the assessment, and the staff at all of the facilities would benefit from additional training and technical support.
- This study explores whether addressing gender constraints in aquaculture can enhance women’s empowerment and climate-adaptive capacities. The study uses a mixed-methods quasi-experimental design and draws on primary data collected in October 2022 in Northern and Luapula provinces, climate change hotspots where gender equality and climate-adaptive capacities are acutely challenged. It examines the extent to which gender-intentional and gender-responsive aquaculture interventions by WorldFish in Zambia that address some of these constraints—such as women’s limited agency and limited access to technology, information and knowledge—are associated with women’s empowerment, better food and nutrition outcomes and enhanced climate-adaptive capacities. The research additionally compares project-level Women's Empowerment in Agriculture Index (pro-WEAI) measures between treatment and control groups.