The health and environmental risks associated with using 17-methyltestosterone hormone (MT) to produce all-male tilapia stocks limit the sustainability of aquaculture. As such, plant-based products with the potential to induce masculinisation in tilapia are gaining considerable attention as potentially safe, nature-based alternatives. However, the underlying mechanism for sex change induction by plant products remains unknown. The present study used pine pollen (PP) to study the processes modulating female-to-male sex change in three-day-old all-female Nile tilapia (Oreochromis niloticus). Experimental fish were fed either a basal diet supplemented with 1,280 mg PP kg− 1 from 3 to 30 days post-hatch (dph), or the same basal diet incorporated with 60 mg MT kg− 1 (MT treatment), or the basal diet only (CT treatment. After 30 dph, fish in all treatments were fed only a basal diet up to 120 dph. Histological observations showed that female-to-male sex change occurred between 21 and 45 dph in MT and PP treatments. During this period, gonadal tissue in PP-treated fish progressively shifted from undifferentiated germ cells toward testes dominated by spermatogonia and spermatocytes. In contrast, MT treatment accelerated spermatogenic progression, with gonads exhibiting advanced germ cells, including spermatids and spermatozoa, reflecting complete masculinisation. Conversely, fish in the CT group underwent normal ovarian differentiation between 21 and 30 dph, characterised by ovarian cavity formation and oocyte-like germ cells. These gonadal histological changes were closely related to temporal changes in sex-biased gene expression and steroid hormone profiles. The PP and MT treatments significantly up-regulated male sex gene expression (dmrt1 and amh) and down-regulated female transcripts (cyp19a1a and foxl2), whereas an opposite pattern was observed in the CT group. Correspondingly, sex steroid concentrations (testosterone and 11-ketotestosterone) were also significantly elevated in both PP- and MT-treated fish, consistent with higher proportions of male individuals (PP: 77.8 ± 2.9

ABSTRACT Nile tilapia ( Oreochromis niloticus ) is among the most widely farmed fish globally that plays a major role in ensuring food security in many low‐ and middle‐income countries. This is attributed to its environmental tolerance, ease of breeding, rapid growth, efficient feed use and high consumer acceptance. As aquaculture production intensifies, bacterial diseases increasingly constrain yields and economic benefits. Although many studies document bacterial outbreaks and have evaluated interventions, heterogeneity across pathogens in virulence, geographic distribution, mortality patterns, environmental drivers and antimicrobial resistance (AMR), together with differences in study designs and outcome, limit a unified understanding of disease risk. Following Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines, we systematically searched PubMed, Web of Science and Scopus; of 689 records identified, 615 remained after removing duplicates, and 399 full texts were assessed after removing 216 articles that were not clearly relevant to the review topic. Of 399 full‐text articles assessed, 87 articles were excluded, yielding 312 studies that met inclusion criteria for qualitative synthesis. This review synthesizes evidence on major bacterial pathogens, epidemiological and environmental drivers, AMR, virulence mechanisms, host innate and adaptive responses, diagnostics and disease management strategies. Streptococcus , Aeromonas , Francisella and Edwardsiella emerged as major bacterial taxa of global importance, although emerging and opportunistic pathogens can also cause severe disease outbreaks under stressful conditions. Disease outcomes reflect interactions among pathogen virulence, host susceptibility, environmental stress, co‐infections and husbandry practices. AMR is an additional One Health concern through resistance selection, horizontal gene transfer, mobile genetic elements and environmental dissemination into aquaculture systems. Sustainable disease management requires integrated, data‐driven strategies that link pathogen surveillance, biosecurity, environmental stewardship and preventive disease management.

The prevalence of micronutrient deficiencies is high among children of 6-23 months whose major dietary source of micronutrients is staple-based porridge. Therefore, this study formulated and developed a safe-nutritious product to supplement micronutrient intake in children of 6-23 months. Silver cyprinid (Rastrineobola argentea) was washed in ash, steam-blanched, dried and extruded before being combined with extruded maize and refractance window-dried pawpaws to generate fortified and blended flours (FBFs). The inclusion levels were 15-45% for silver cyprinid, 5-15% for pawpaws and 50-80% for maize. Following the optimisation, FBF sample 7, formulated from 50% maize, 45% Silver cyprinid and 5% pawpaw, was the most cost-effective, nutritious, palatable and shelf-stable over a six months' storage duration. Nutritional analysis per 100 g revealed FBF sample 7 contained protein: 31 g calcium: 800 mg, phosphorus: 0.9 mg, iron: 61 mg and zinc: 12 mg. The product was free from Salmonella, with aflatoxin undetected and total coliform counts below 10cfu/g. FBF sample 7 had significantly higher protein (p < .05), zinc (p < .05) and iron (p < .05) than the rest of the 13 samples. The formulation meets nutritional requirements for children aged 6-23 months and demonstrates strong potential to contribute to alleviating the nutritional deficiencies among infants and young children globally.

ABSTRACT Oreochromis species are of economic importance in fisheries and aquaculture but threatened by human‐mediated activities. Effective conservation and their sustainable management require genetic monitoring tools that can assess genetic variation across species. Various neutral markers have been used to monitor biodiversity in organisms, but they are limited in cross‐amplification among various taxa. Non‐neutral markers such as Exon‐Primed Intron Crossing (EPIC) not only cross amplify various taxa but also target gene regions that are likely to be involved in adaptive responses to selective pressure. This study therefore developed 50 EPIC markers from Oreochromis niloticus reference genome targeting immune related genes to assess their potential to cross‐amplify Oreochromis species. Genetic diversity, population structure, and differentiation was measured among Oreochromis niloticus, O. jipe, O. esculentus and O. leucostictius species and their respective populations from eleven African water bodies and two aquaculture farms. 45 EPIC markers successfully amplified target regions across the four Oreochromis species. O. niloticus exhibited the highest diversity (He = 0.50), followed by O. jipe (He = 0.29), O. leucostictus (He =0.28) and O. esculentus with the lowest (He = 0.25). The highest differentiation values were observed among populations of different species while the lowest was among farmed O. niloticus. This was supported by AMOVA results that showed highest genetic differentiation among species. Population structure analyses were concordant with species boundaries while showing detailed intraspecific clustering patterns among the O. niloticus populations that reflected geographical origin. The observed genetic diversity, gene flow, and population differentiation confirms the applicability of EPIC markers as molecular tools for monitoring biodiversity and guiding the conservation of Oreochromis species under increasing anthropogenic and environmental pressures.

Aquaculture generates substantial amount of residual feeds and faecal matter that accumulate in the culture environment and pollute effluent-receiving water, diminishing its ecological functioning. To devise means of treating nutrient-rich aquaculture wastewater, the efficiency of integrated papyrus-bivalve mesocosms in removing nutrients was evaluated. The mesocosms were fed on water (6600 L) from one brood-stock pond and allowed to settle for 2 weeks. Physico-chemical parameters, including nutrient level in influent and effluent of mesocosms, were analysed fortnightly using standard methods. The integrated papyrus-bivalve mesocosms had the highest removal of 69.5, 52.9, and 70.5

The quantities, diversity, and frequency of pesticide application among rice farmers in Malawi are steadily increasing to improve crop production. Inappropriate handling and application of pesticides expose farmers and the environment to adverse health risks. The study investigated the level of knowledge on pesticide handling and respective effects on both environment and human health. A semi-structured questionnaire was used to collect data in the survey involving 399 randomly selected rice farmers. Descriptive statistics analyzed farmers’ socio-demographic profiles and their knowledge of different aspects of pesticide application. Chi-square tests explored the association between socio-demographic characteristics and farmers’ knowledge of different aspects of the pesticides. Logistic regression models were fitted for each binary outcome and the socio-demographic characteristics. Male farmers aged 55 years and above with education above secondary level were 0.42 times less likely to observe self-protection, aware of the toxicity of different chemicals and the associated environmental effects, hence handled and applied pesticides responsibly. Farmers identified headache and respiratory disorder as the common human health conditions associated with pesticide use. Likewise, more educated farmers, beyond secondary level were 2.37 times more likely to handle good or better pesticide handling and aware of dangers on environmental degradation. The study found that farmers lacked adequate knowledge about optimal pesticide usage and had insufficient understanding of proper pesticide handling and its respective impacts on humans and the environment. Proper training and information sharing among farmers’ groups are needed.

This study provides information on the length-weight relationship and condition factor of Bagrus bayad, a fish species from Lake Albert.These variables were analysed from 520 samples collected from Lake Albert (DR Congo) between January and December 2020.The mean total length and total weight of B. bayad, (combined sexes) were 47.43 ± 7.81 (cm) and 495.34 ± 293.36 (g), respectively.The b-value of the weight-length relationship varied from 2.20 to 3.21.Males exhibited a negative allometric growth while females showed isometric growth.There was a strong positive correlation between length and weight, of B. bayad (i.e., LnTW = 2.72LnTL -1.88; R 2 = 0.875) and for females (i.e., LnTW = 2.742LnTL -1.95; R 2 = 0.739).The length-weight ratio for both sexes was (LnTW = 2.8812LnTL -2.1686) with a correlation coefficient r 2 = 0.837.B. bayad exhibited negative allometric growth pattern.

The potential of pine pollen (PP) to masculinize sexually undifferentiated Nile tilapia was evaluated by feeding graded levels of PP (0.08–3.20 g kg-1 basal diet) to triplicate groups of three-day-old Nile tilapia for 28 days. Masculinization and associated differences in growth were compared to fish individuals fed the same basal diet with no PP (CT; negative control) and with 0.06 g 17α-methyltestosterone (MT) kg-1 basal diet (positive control). Both PP and MT treatments significantly skewed the expected 50:50 (male: female) ratio towards more male individuals. Notably, MT and 1.28 g PP kg-1 of diet produced a significantly high proportion of males (89.2 ± 2.2% and 80.0 ± 2.9% respectively), compared to 50.8 ± 2.2% in the CT treatment (P < 0.001). Except for 0.08 g PP kg-1 of diet, the final body weight and specific growth rate of individuals fed PP and MT-supplemented feeds were significantly higher than fish from the CT group. Although 1.28 g PP kg-1 diet produced the highest masculinization, the fish fed 3.20 g PP kg-1 diet had the highest final weight (14.73 ± 0.54 g), suggesting the presence of growth enhancers in PP. Similarly, a superior feed conversion ratio was recorded in both PP and MT-treated groups compared to the CT treatment (P = 0.024). However, the condition factor and survival rate of fish in all groups did not differ significantly. Overall, 1.28 g PP kg-1 diet was potent in sex inversion and promoted the growth of Nile tilapia, making PP a promising alternative to MT in the production of all-male stock.

Effect of smoking technologies on nutritional quality and concentration levels of polycyclic aromatic hydrocarbons (PAHs) in Mormyrus caschive and Oreochromis niloticus were determined to enable adoption and utilization of suitable facility that maintains good quality for sustainable supply of nutritious fish products in South Sudan.A total of 72 fresh M. caschive and O. niloticus were purchased, of which 24 were iced for reference and the other 48 were divided into two groups for pit and chorkor smoking.Experimental smoking of fish samples was conducted twice in a randomized design.Fish samples were analyzed for nutritional values using standard methods of the association of official analytical chemists and levels of PAHs using gas chromatography-mass spectrometry.Results revealed; the two smoking methods concentrated crude protein, fat and ash contents.However, fish smoked using chorkor had significantly higher nutritional values than fish smoked using pit kiln.About seven types of PAHs comprising of low and medium molecular weight were recorded from the two smoked fish species.Naphthalene and fluorene were the two dominant PAHs with fish smoked using pit kiln having significantly higher concentration levels of naphthalene (5.86±4.16µg/kg) and fluorene (3.83±0.10µg/kg) than fish smoked using chorkor oven.The study concluded that chorkor oven has better quality smoked fish than pit.Hence, its utilization and adoption for artisanal fisheries in South Sudan is recommended.

Efficacy, cost and benefit of smoking fish using pit and chorkor technologies were investigated to inform decisions on economic sustainability and efficiency of the processing technologies in removing moisture content for quality assurance and extension of fish shelf-life. A total of 72 fresh fish; 36 (120 kg) Mormyrus caschive (Family: Mormyridae; common name: Elephant snout) and 36 (118 kg) Oreochromis niloticus (Family: Cichlidae; common name: Nile Tilapia) were bought from Sur-num fish landing site. From the procured fish, 12 (38 kg) samples were iced and used for fish moisture content analysis while the remaining 60 samples were divided into two batches for pit and chorkor smoking. Each batch contained 30 fresh fish samples with a total weight of 100 kg. Field experimental smoking was conducted twice in a completely randomized design. Moisture content in fish samples was determined using weight reduction method and cost benefit analysis using market price survey and interviews. Results revealed chorkor oven significantly reduce moisture content in M. caschive (10.0±0.83%) and O. niloticus (15.1±0.48%) more than pit kiln (15.3±0.57% and 17.3±0.42%), respectively. Although chorkor oven construction was expensive, the economic return was higher than for pit kiln due to short smoking time (6-8 hours, and twice in 24 hours) and utilization of small quantity of firewood (4 bundles/round). Chorkor oven is therefore, an efficient and economically viable technology for smoking fish. The study recommends its adoption for artisanal fisheries in South Sudan.

Determining the genetic characteristics of natural fish stocks is useful for conservation and aquaculture programs. For African catfish, Clarias gariepinus, genetic characterization could help identify populations suitable as brood stock for culture, and those in need of conservation. This study determined the genetic diversity, population structure, and demographic history of C. gariepinus from Lakes Victoria (LV), Kenyatta (LKE), Kamnarok (LKA), and Rivers Nyando (NR), Tana (TR) and Sosiani (SR) in Kenya. Using 128 DNA sequences of D-loop control region, 34 haplotypes were recovered, of which 79.4% were singletons. Only 7 haplotypes were shared between sites, implying little gene flow between sites. Number of haplotypes was highest in LKE and NR populations and lowest in SR. Haplotype diversity was highest in LV, and lowest in SR, while, nucleotide diversity was highest in LKA and lowest in LV. Phylogenetic analyses revealed five clusters: Lakes Victoria, Kamnarok and Kenyatta, and Rivers Tana and Nyando, from both maximum likelihood tree and minimum spanning network. This, together with significant FST values among the sites imply population differentiation. Mismatch distributions were multi-modal in LKA, LKE, NR and TR, signifying demographic equilibria. Neutrality tests Tajima`s D values for the sampled populations were negative and significantly different, suggesting stable populations. These results show the existence of genetically distinct populations of C. gariepinus that require spatially explicit management actions such as reducing fishing pressure, pollution, minimizing habitat destruction and fragmentation for sustainable utilisation of stocks.

Control of prolific reproduction is vital for a profitable tilapia aquaculture enterprise. All-male tilapia culture is a popu-lar method used to control prolific breeding, because the male individuals grow faster than female and mixed-sex populations. Presently, most farmers use 17 α -methyl testosterone (MT) to produce all-male tilapia individuals, although synthetic hormones are linked to human health and environmental risks. Recently, considerable attention has focused on plant-based products as alternatives to MT, because they are affordable, safe, and eco-friendly. Despite the growing interest in using plant extracts to prevent fre-quent spawning in tilapia production, the available information is not collated to standardize application guidelines. Accordingly, this review article consolidates existing knowledge on the use of plant extracts to control prolific breeding in tilapia culture systems. In addition, limitations to commercial application of the extracts are identified. To date, seed, root, and leaf extracts of 20 plant species, most notably, Tribulus terrestris, Mucuna pruriens, and Carica papaya , exhibit potential for controlling unwanted breeding in tilapia production systems. The extracts are mainly administered orally, incorporated in fish feeds. Saponins and flavanoids are the main bioactive compounds in the phytoextracts, which induce sex inversion and fertility impairment in tilapia. The commercialization of plant extracts is, however, hampered by lack of standardized information on extract preparation, optimal dosages, and mechanism of action. Thus, future studies should address these technical limitations and highlight economic incentives for commercial use of plant extracts in tilapia aquaculture. plant extracts' application in controlling unwanted spawning in tilapia aquaculture, as an alternative to the currently, most used synthetic hormones.

Summary Most recirculation aquaculture systems (RAS) use aerated biofilters to maintain suitable water quality for fish production. However, application of non-aerated biofilters may provide opportunities to lower aeration costs, water usage and concentration of all nitrogenous wastes in the effluent water. Our study aimed at comparing the biofiltration performance characteristics of two biofilters: a conventional aerated biofilter and a non-aerated biofilter receiving the same effluent water from a small-scale RAS. The two biofilters were evaluated in triplicate and tested concurrently for seven months. Water quality parameters were monitored at the biofilter inlets and outlets and in the fish tanks. At the beginning of the experiment, the concentration of ammonia at the two biofilter outlets were not significantly different. However, the concentrations decreased with time reaching mean values of 1.33 ± 0.02 mg L−1 and 1.23 ± 0.21 mg L−1 N-NH4 in the aerated and non-aerated biofilters, respectively. Whereas phosphorus and nitrate levels were significantly high in the aerated biofilter. There was no significant difference in the growth of fish between the aerated and non-aerated biofilters. The results suggest that non-aerated biofilters can be as effective as aerated biofilters in maintaining suitable water quality for O. niloticus production.

The effect of smoking kilns on water activity, microbial load and sensory attributes was evaluated to adopt suitable technology that maintains the quality of fish in South Sudan. A total of 300 fresh Mormyrus caschive and Oreochromis niloticus were purchased, 36 fresh samples were iced and the remaining 264 fish samples were divided into two batches for pit and chorkor smoking. The experiment was done twice in a completely randomized design. Fish samples were analyzed for water activity using Lab-Swift Meter, microbial load using standard microbiological methods and sensory characteristics using 9-point hedonic grading scale. Result revealed that, water activity in pit smoked fish increased at a rate of 1.7 times faster than in chorkor smoked samples during storage. Corresponding to water activity, plate count equally increased at a rate of 1.7 times faster for pit smoked M. caschive and 1.1 times for O. niloticus than samples smoked using chorkor. Similarly, mould load increased at a rate of 1.5 times faster for pit smoked M. caschive and 2.2 times for O. niloticus than samples smoked using chorkor oven. Overall, chorkor smoked fish had significantly better sensory parameters than pit smoked samples after one month’s storage. Therefore, chorkor kiln produced quality smoked fish in terms of microbial load and organoleptic parameters, and the study recommends its adoption for artisan fisheries in South Sudan. However, microbial characteristics of smoked fish need to be further examined for a period exceeding a month to determine microbiological quality and establish fish self-life in order to maintain the quality and safety of fish and fisheries products. Key words: Water activity, microbial load, sensory attributes, smoking technologies, shelf life.

Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.

：Approximately 200 million people in Africa derive high-quality and low-cost proteins from fish. However, the consumption of fish is not fully exploited to combat the “triple burden” of malnutrition—obesity, undernutrition, and micronutrient deficiencies which are the leading causes of poor health in the region. There is still limited knowledge on quantitative information to guide policy makers in developing evidence-based actions that can improve the availability of and access to nutritious food for healthy and sustained diets among children and care givers. In this paper, we review the available literature with the aim of assessing and quantifying the extent to which fish contributes towards fighting food and nutrition insecurity in the Eastern Africa subregion. Key results reveal the region is characterized by fish supply deficits, and hence, low levels of fish consumed per person. Nonetheless, the increase in fish imports, and the growing supply of fish from aquaculture are likely to improve the per-capita fish intake. Fish trade is generally bidirectional, with exports exceeding imports in value terms, while significant challenges still hinder domestic and intra-regional fish trade. The Eastern Africa region is projected to realize increased fish consumption from 4.80 kg in 2013 to 5.49 kg by 2022. Rising population growth and income levels imply that the region will need 2.49 million tonnes of fish to fill the demand–supply gaps. We recommend that food security and nutritional programmes should recognize the potential of fish in providing essential micronutrients from the aspects of improved dietary quality, nutritional status, and general wellbeing of the region’s fast growing population.

Fish and fishery activities contribute significantly to livelihoods through provision of nutritious food, employment and generation of revenues for local and national governments (FAO, 2016ab). It is an important and cheap source of protein to low income earners. Fish forms more than 50% of the essential animal protein and mineral intake for over 400 million people from developing countries (FAO, 2016bc). It is estimated that over 1.7 million South Sudanese depend on fisheries for their livelihoods (FAO, 2018). The contribution and importance of small-scale fishing to household livelihoods in South Sudan increased from 6.8% to 10.2% from 2015 to 2016, indicating greater reliance on this source of income (FAO, 2018). FAO (2016a) estimated that over 10 million people in developing countries are engaged in fisheries activities mainly as fishers, processors and vendors. However, fisher folks in South Sudan are faced with high postharvest losses due to lack of proper processing and preservation techniques (CAMP, 2013). Thus, poor handling of fish catches leads to significant physical, nutritional and economic losses (FAO, 2015). Deterioration in fish quality is one of the main sources of nutritional and economic losses in South Sudan (FAO, 2018). Fisher folks reported insect infestation, animal attacks and fragmentation as the main causes of physical loss of fish and fishery products. Processing and preservation of fresh fish are important to prevent quality, nutrient and economic losses because fish is highly susceptible to deterioration immediately after harvest. Hygienic handling of fish is important to achieve the best quality and highest possible profits. Despite the immense contributions, fishing industry in South Sudan suffers from enormous postharvest losses which are estimated at 40% in dry season and 60% in rainy season (FAO, 2016). Fish postharvest losses have a profound adverse impact on rural fishing population whose livelihoods often depend on fisheries activities. Lack of proper infrastructure for fish postharvest handling is a major challenge facing rural fishing communities of South Sudan. As such improved processing and preservation techniques are needed to reduce adverse effects of fish postharvest losses. Among the traditional preservation methods such as salting, sun drying and fermentation, fish smoking is the dominant type of fish preservation technique in Terekeka State. This is due to the fact that most consumers prefer smoked fish to sun dried, wet salted and fermented fish. Besides lack of proper processing and preservation, infrastructures have made fisher folks to extensively use smoking to preserve their catches which cannot be delivered to distant markets in fresh form. Indeed, effective and efficient smoking of fish maintain the quality and safety of smoked fish due to antioxidants and preservatives contained in the smoke (Kumolu-Johnson et al., 2010; Olayemi et al., 2012; Magawata and Musa, 2015). The safety and quality of smoked fish help consumers in making choices regarding various processed fish products which also influences the market price (Nunoo and Kombat, 2013; Nguvava, 2013). Corresponding Author: Dr. Peter Pakoll E-mail addresses: pakoll@ac.cns.mak.ug © 2019 JONARES all rights reserved ABSTRACT The effect of smoking kilns on nutritional value and safety of smoked fish was determined using a total of 300 fresh Mormyrus caschive and Oreochromis niloticus. 36 fresh samples were iced and the remaining 264 samples were divided into two batches for pit and chorkor smoking. Samples were subjected to chemical analyses according to the methods of the association of official analytical chemists (2005). Microbial load was investigated using standard methods of bacmteriological analytical manual (2005). Results revealed that chorkor significantly reduced moisture content in smoked M. caschive (10.0±0.83%) and O. niloticus (15.1±0.48%) more than pit by 15.3±0.57 % and 17.3±0.42%, respectively. Thus, effective removal of water from fish is attributed to the concentration of heat associated with enclosed characteristics of chorkor kiln. Although both smoking methods concentrated crude protein, fat and ash contents, chorkor smoked fish had significantly higher nutrient concentrations than pit because of effective removal of water content from fish. In both species, the water activity in pit smoked fish increased at a rate of 1.7 times, faster than in chorkor smoked samples. Corresponding to water activity, microbial load increased at a rate of 1.7 times faster for pit smoked M. caschive and 1.1 times for O. niloticus than the samples smoked using chorkor kilns. Similarly, molds increased at a rate of 1.5 times faster for pit smoked M. caschive and 2.2 times for O. niloticus than samples smoked using chorkor. Chorkor therefore, produces better quality smoked fish in terms of nutrients and safety, hence this study recommends its adoption for artisan fisheries in South Sudan.

The maintenance of optimal water quality for fish production is one of the major challenges in aquaculture. Aquaponic systems can improve the quality of water for fish by removing the undesirable wastes and in turn produce a second marketable crop. However, there is no information on the growth and nutrient removal capability of Artemisia annua in aquaponic systems. This study evaluated the effect of plant density on water quality, the growth of A. annua and Oreochromis niloticus in a small scale aquaponic system in Kenya. The aquaponic system consisted of three treatments representing different plant densities (D1: 48 plants/m2, D2: 24 plants/m2 and D3:0 plants/m2). The high plant density system contributed significantly (p < 0.05) to the removal of all nutrients. The removal efficiency of ammonia was significantly higher in D1 (64.1 ± 14.7%) than in D2 (44.5 ± 6.8%) and D3 (38.0 ± 12.1%). Nitrates and nitrites were inconsistent, whereas phosphorus increased gradually in all treatments. The productivity of plants was higher in D1 than D2. Fish growth rates were significantly higher in D1 (0.35 ± 0.03 g/d) and D2 (0.32 ± 0.02 g/d) than in D3 (0.22 ± 0.04 g/d). The results show that A. annua can be cultivated in aquaponic systems due to its nitrogen removal capabilities.