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Cover image: Many mackerel fish, underwater view;© Yellowj/Shutterstock, Abstract blue watercolor flow wet on wet paper; ©501room/Shutterstock. [Extracted from the article]

Kenya is a major player in the global ornamental trade, exporting substantial quantities of ornamental fish to the global market. The sector plays an important role in the country's economy through foreign exchange. However, the country's ornamental fish industry has not fully developed to generate more economic benefits. This paper sought to identify the existing opportunities for enhancing the production and trade of ornamental fish in the country. The findings reveal that there are opportunities for collection of native freshwater ornamental fish species from the vast freshwater resources in the country; for the culture of marine ornamental fish; for public aquariums as centres of recreation, conservation, research and education; and for employment and development of support industries. The findings also show that there are international legislations and national policies that create an enabling environment for the growth of the industry. To unlock the full potential of the industry, training and research, investment and infrastructure development, quality assurance, collaboration and networking, and environmental sustainability strategies need to be put in place. This will ensure Kenya's position as a key player in the global ornamental fish trade. [ABSTRACT FROM AUTHOR]

The increase in hard artificial structures in the marine environment is contributing to ocean sprawl. As well as adding hard structure to the seabed, mussel aquaculture adds rope droppers and anchor lines to the water column, where such structure would otherwise be absent. This paper aims to monitor the effects of mussel headlines on the pelagic fish community over time, as well as to investigate whether there is an interaction between the age of cultivated mussels with the number of epibiota species and the abundance of pelagic fishes. Two surveys were carried out: a time series monitoring survey to assess whether the mussel headlines change the surrounding fish species relative to control areas over time, and a fish aggregation device effect survey to investigate whether older and larger mussels support greater abundances of pelagic fishes and epibiota. The most abundant fish species was Atlantic horse mackerel, Trachurus trachurus, with significantly greater numbers recorded around ropes growing older mussels. Results from the surveys show that the physical farm infrastructure has provided a substrate for colonisation by a variety of epibiota: A total of 21 species were recorded growing on the mussel ropes. Furthermore, the older and larger the mussels become, the greater the numbers of epibiota taxa that can colonise, coupled with a greater abundance of pelagic fish recorded around the ropes. The sustainable development of offshore Blue Industries is essential to produce renewable resources. This study brings essential evidence for marine managers and regulators that offshore mussel farming can provide benefits for pelagic and benthic species of both conservation and commercial importance while producing sustainable protein to feed a growing population. [ABSTRACT FROM AUTHOR]

Poor and unreliable knowledge of the status of freshwater fisheries limits their inclusion in governance processes, thereby impeding effective management measures. This threatens the livelihoods of people, particularly in developing countries. Improved knowledge is required to draw the attention of policymakers and stimulate effective management measures to accelerate the sustainability of the freshwater fisheries. In line with this requirement, this paper provides the state of knowledge of the aquatic ecosystem and fisheries of the Lake Edward system, East Africa, focusing on lakes Edward, George and the Kazinga channel. The state of knowledge was accomplished by reviewing existing data and information on aspects of primary productivity and water quality, invertebrates, fish fauna, fish life history and ecology, and fisheries. The waterbodies have been monitored since the 1930s, albeit sporadically, providing data on all the above aspects but with substantial temporal gaps. Adequate and updated data and information exist on the water quality status of the water bodies, extant aquatic taxa (including fishes) and fish catches but with uncertainties in the latter. Data and information gaps exist on the abundance of biotic communities, fish life history, quantitative trophic ecology and fisheries management reference points. The aggregated data and information can directly support decisions for fisheries management. We recommend regular monitoring to fill the data and information gaps, more comprehensive stock assessments and the development of aquatic ecosystem models. [ABSTRACT FROM AUTHOR]

To allow sea urchin aquaculture to achieve its intended scale, efficient and precise methods for measuring large numbers of urchins in commercial‐scale operations are needed. Current protocols for measuring urchin test (shell) dimensions and mass are time‐consuming and prone to high measurement error, thus inconvenient in research and impractical in a commercial context. This study investigates and compares various measurement methods with a newly developed computer vision approach developed in this study, to establish a single protocol using precise, efficient and accessible methodology for measuring live urchins. We show that urchin wet mass can vary up to 8.73% depending on time out of water; this is significantly reduced to an average of 0.1% change by allowing urchins to drip‐dry for at least 90 s prior to weighing. We found the conventional vernier calliper method used to measure urchin dimensions to be both time‐consuming and imprecise (mean coefficient of variation (CV) of 2.41% for Tripneustes gratilla). Conversely, the computer vision programme we developed measures with higher precision (mean CV of 1.55% for T. gratilla) and is considerably faster. The software uses a series of hue saturation value filters, edge detection algorithms and distortions to measure the diameter of the test (excluding spines) of multiple urchins at once. The software is open‐source, and the protocol does not require specialised equipment (can be performed with a mobile phone camera). When the computer vision application is combined with the simple procedures described in this paper, to reduce measurement inaccuracies, urchin wet mass and diameter can be more efficiently and precisely determined. For a larger scale context, this software could easily be incorporated into various tools, such as a grading machine, to completely automate various farm processes. As such, this study has potential to assist urchin data collection in both research and commercial contexts. [ABSTRACT FROM AUTHOR]

Increased food demand, reflecting a rising global human population, attaining 8 billion in 2022, has furthered the intensification of farmed aquatic animal production. Intensification practices can be resource demanding for micro and macronutrients, dedicated feeds, fossil fuels, chemotherapeutics, and water. Water replaces evaporative losses and may be used to dilute nutrient-rich wastewater. As an alternative to wastewater discharge, biofloc technology (BFT) uses microbes to manage nutrient levels in production systems. Amicrobial community grown at high densities can assimilate waste metabolites for growth. This is promoted by increasing the carbon--nitrogen (C:N) ratio using a combination of aquafeed fed to the fish and an additional carbohydrate source, for example, starch, molasses, or bran. The microbial biomass offers a continuous and additional food source to the farmed animal, thus reducing the need for finished aquafeeds and lowering the feed conversion ratio. Although the approach relies on multiple interacting species, BFT can be deployed in relatively low technology settings. This review considers the basis of BFT and identifies areas for innovation and expansion. For example, control of light quantity and quality can influence the biofloc and hence the growth of cultured species. Research on biofloc aquaculture is dominated by studies using tilapia and shrimp, but the technology could be applied to other species, particularly species that are tolerant of biofloc conditions and not highly carnivorous. Biofloc may be a useful biosecurity tool for all or part of the life cycle, and meals made from dried biofloc may enhance the production of cultured species. The key benefits of BFT can potentially be seen in reduced water consumption, lower feed requirements, and improved fish health. This review differs from current review papers in proposing the use of a life cycle assessment in conjunction with BFT, which may be a useful tool for describing and communicating the relative benefits of biofloc systems and their wider environmental impact. This study will serve as a useful knowledge base of BFT information for students, researchers, and stakeholders alike, offering a central source of the main aspects around the culturing of biofloc, key parameters, common species used, areas of potential improvement, and a discussion on where the future of BFT may lie. [ABSTRACT FROM AUTHOR]

Cover image: Many mackerel fish, underwater view;© Yellowj/Shutterstock, Abstract blue watercolor flow wet on wet paper; ©501room/Shutterstock. [Extracted from the article]

Fish aquaculture has become the fastest growing sector in global food production. Thus, ensuring the sustainability of aquaculture practices is of the utmost importance. Studies in higher vertebrates (i.e. mammals) have demonstrated the role of the host microbiome in physiological processes from nutrient acquisition to pathogen protection. Therefore, analysis of fish microbiomes is an important factor to consider with regard to overall animal health and welfare. Rainbow trout (Oncorhynchus mykiss) are an economically valued fish cultured worldwide. Several studies have identified microbial constituents inhabiting the intestinal tract of rainbow trout. To better elucidate some of the core constituents of the rainbow trout intestinal microbiome, this systematic literature review analysed the relative abundance results from 25 articles published on the rainbow trout intestinal microbiome from 2017 to 2021. Bacteria classified within the phyla Firmicutes and Proteobacteria were observed in every study. At the family level, Lactobacillaceae was consistently observed. Additionally, bacteria in the Actinobacteria, Bacteroides, and Tenericutes phyla were identified in at least 50% of the studies. Interestingly, Mycoplasma spp. were occasionally the most dominant organisms present in the microbiome. Overall, the results here identify bacteria that are commonly found members of the rainbow trout intestinal microbiome. [ABSTRACT FROM AUTHOR]

Inland aquaculture operations are practised all over the world, contributing about 62.6% of all farmed aquatic animals. This venture is increasing worldwide and outpacing the global market demand for fish and fishery products driven by competition with other animals, over‐population and over‐exploitation of wild capture fisheries. These operations expand globally, associated with the degradation of the culture environment due to poor aquaculture management practices and algal blooms due to nutrient influxes as well as high demand of quality fish feeds of affordable price. To overcome these challenges, sustainable, healthy and environmentally friendly alternatives including probiotics application must be adopted to achieve better production, profitability and productivity as well as a resilient culture environment. In this review, information on potential applications of probiotics in aquaculture (inland aquaculture) focused on sources, safety, approved probiotics for aquaculture, characteristics of probiotics, mode of applications and its potential use on pathogenic microbes control, fish haematological parameters, growth performance and stress responses, water quality parameter, anti‐nutritional factors and feed digestibility, limitation of using probiotics in aquaculture and lastly future perspectives on the probiotics application in aquaculture industry were reviewed and compiled for future sustainable aquaculture production and productivity and environmentally friendly. The review has also highlighted all probiotics application and their approved authority for use in farmed freshwater fish (Nile tilapia Oreochromis niloticus, Catfish Clarias gariepinus, rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio) and their cultured environment worldwide. Therefore, the review has comprised all information on the potential benefits application of probiotics in an inland aquaculture for public documentation and also identifies gaps in the aquaculture industry that require further research and assessment. [ABSTRACT FROM AUTHOR]

The study aimed to assess the impact of stocking density on the growth performance, survival rate and production of seabass (Lates calcarifer) fingerlings in floating net cages conducted at the Maheshkhali Channel, Cox's Bazar, Bangladesh. A triplicate group of seabass, with an average initial weight of 86.82 ± 1.9 g, was randomly stocked in floating net cages at densities of 15, 12, 10 and 8 fish m−3, referred to as T15, T12, T10 and T8, respectively. The fish fingerlings were supplied with freshly chopped sardine (Sardinella fimbriata) at 10% of their body weight for 4 months and 5% for 2 months, administered twice daily. The water quality metrics were measured fortnightly. The initial and the final proximate composition of seabass was not significantly different (p > 0.05). Upon completion of the experiment on the 180th day, the growth performance and additional measures, including final body weight, weight gain (WG), percent weight gain (PWG), specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency ratio (FER), survival rate and total production, were assessed. Comparisons of growth and yield demonstrated that fish stocking density significantly (p < 0.05) influenced growth and productivity. Fish cultivated at maximum density (T15) exhibited lower mean weights than those raised at lower densities. This study demonstrated that T10 had better results for all growth and other metrics examined, indicating the appropriateness of this density. Therefore, it may be inferred that seabass exhibits optimal growth at a stocking density of 10 fish m−3 along the coast of Cox's Bazar, Bangladesh. [ABSTRACT FROM AUTHOR]

The mass production of release‐size H. scabra juveniles in the Philippines is primarily done in a floating hapa ocean‐based nursery systems. To optimize its production, understanding the influence of different culture conditions and their management is necessary. In this study, the effects of hapa net cleaning interval, hapa layers, and stocking density on growth and survival of sandfish juveniles reared in floating hapa (L × W × H: 1.7 m × 0.9 m × 1.2 m) nursery system were assessed in two 60‐day field studies. Results showed that the number of hapa net layers and cleaning interval had negligible effects on the growth performance of sandfish juveniles by day 30. However, sandfish juvenile survival was affected by hapa net layers with higher survival in triple‐layer mosquito net hapas (40.5 ± 0.97%) compared to double‐layer mosquito net hapas (17.8 ± 0.62%). By day 60, the growth performance of sandfish juveniles in double‐layer hapas was higher (average weight: 5.0 ± 0.97 g; AGR: 0.13 ± 0.03 g day−1) compared to that in triple‐layer mosquito hapa nets (average weight: 3.1 ± 0.23 g; AGR: 0.07 ± 0.01 g day−1). Survival of sandfish juveniles reared in double‐layer mosquito net hapas, cleaned at 5‐day intervals (85.9 ± 4.58%) was significantly lower compared to all other treatments. Conversely, initial juvenile stocking density did not significantly affect the growth performance and survival of sandfish juveniles in both rearing cycles. We therefore recommend the use of triple‐layer mosquito net hapas during the first 30‐day culture period and an initial stocking density of 1000 post‐settled sandfish juveniles to increase production output. After 30 days, when the juveniles are larger, the use of double‐layer mosquito net hapas and lower stocking density are recommended to reduce cost and enhance growth performance. Where cleaning is necessary, hapa nets may be cleaned at 10‐day intervals to improve survival. The results of this study have important implications for optimizing the production of release‐size sandfish in ocean‐based nursery systems in the Philippines. [ABSTRACT FROM AUTHOR]

The present study was undertaken to evaluate the antioxidant and antimicrobial activity of chitosan‐alginate‐coated phycocyanin (PC) extract from Spirulina sp. on Penaeus semisulcatus infected with Salmonella typhimurium stored at 4°C and 8°C for 21 days. Four groups of shrimp treatments—a control sample (without infection and PC), an infected sample without PC, a non‐infected sample + PC and an infected sample + PC—were used. The toxicity test revealed no toxicity of PC against Caenorhabditis elegans. The results of the pH, thiobarbituric acid, peroxide value (PV) and total volatile basic nitrogen showed that the lowest amounts of these factors were observed in the samples immersed in PC, whereas the highest values belonged to the samples infected with Salmonella. On the basis of the total number of bacteria in food (log 10⁷ CFU/g), the shelf life of shrimps treated with PC increased by 14 and 4 days at 4°C and 8°C, respectively, compared to the control. The diphenyl‐2‐picrylhydrazyl (DPPH) and ABTS results of the antioxidant activity indicated that the highest values were observed in the infected sample + PC after 21 days at 4°C and 8°C (82.65 ± 0.36 and 89.50 ± 0.43), respectively. The results of the colour assessment showed that the highest and lowest values belonged to the control sample (without infection and PC) and the non‐infected sample with PC, respectively. The results of sensory analysis showed that the samples enriched with PC had a higher overall acceptability than samples without PC. In conclusion, PC increased the shelf life of shrimp infected with Salmonella sp. [ABSTRACT FROM AUTHOR]

The present study provides a comprehensive analysis of the population structure (length–frequency distributions), growth pattern (length–weight relationships [LWRs] and length–length relationships), physiological condition factors (allometric [KA], Fulton's [KF] and relative [KR]), relative weight (WR) and form factor (a3.0) of Chanda nama. A total of 1200 specimens were collected from the Old Brahmaputra River, northeastern Bangladesh, for 12 months by traditional fishing gear, including seine net and cast net. The total length (TL) of several individuals varied from 2.3 to 7.2 cm. The highest percentage contributed to the population's 4.0–4.5‐cm‐sized group. The LWRs indicated a positive allometric growth pattern (b > 3.0). Fulton's condition factor significantly correlated with TL and body weight (p < 0.0001). The calculated WR ranged from 67.38 to 137.64. No significant variations from 100 were found using the Wilcoxon rank test (p = 0.034), suggesting that C. nama might live there in a balanced predator–prey environment. Furthermore, the measured value for the form factor (a3.0) was 0.0105. In addition, fish with a TL of 7–8 cm should be caught since they are in good condition and have enough meat. The study's findings will greatly contribute to the efficient and enduring management of C. nama in the Old Brahmaputra River and its adjacent ecosystems. [ABSTRACT FROM AUTHOR]

Seaweed is multicellular marine macroalgae that enhances the immunity of aquatic organisms. The study was designed to assess the ethanolic extract (EtOH) extracted from red seaweed (Gracilariopsis lemaneiformis) on Nile tilapia (Oreochromis niloticus) to evaluate growth, immunity and haematological parameters. The EtOH was applied with fish feed in four treatments such as T1‐control (0% EtOH), T2 (5% w/v EtOH), T3 (10% w/v EtOH) and T4 (15% w/v EtOH) each with three replicates. The initial average weight of the fish was 17.53 ± 2.1 g. Results showed that the growth increased gradually with the percentage of red seaweed extract, whereas the mean weight gain was found significantly higher in T4 (51.5 ± 4.2) than in the control. The specific growth rate (%) and survival rate (%) were found higher in T4 at the lowest FCR compared to other treatments (p < 0.05). The blood haemoglobin level of Nile tilapia was higher in T4 (11.5 g/dL) and lowest recorded in T1 (7.5 g/dL). However, the level of blood glucose interacted inversely with blood haemoglobin. The plasma protein level was also varied among the treatments (p > 0.05). The blood parameters, refractive index (RI) and spleen somatic index (SSI) were significantly different among the treatments. The RI of blood plasma and SSI were found to be better in T4 treatment. The research indicated that red seaweed extracts significantly enhanced the growth and boosted the immunity level of Nile tilapia. [ABSTRACT FROM AUTHOR]

A major expense in the operation of bivalve nurseries is the culture of high‐quality live microalgae feeds, and efforts to develop effective alternative feeds have had limited success. Juvenile bivalves are known to be able to absorb dissolved nutrients, but this ability has received minimal attention as a route for supplementary feeding. This study assessed the capacity of juvenile green‐lipped mussels (GLMs) (Perna canaliculus) to uptake and assimilate dissolved glucose at five experimental concentrations (i.e. 10 µg mL−1, 100 µg mL−1, 1 mg mL−1, 10 mg mL−1 and 30 mg mL−1) as a supplement to cultured microalgae. Growth and survival of the mussels were measured over 3 weeks. Although all glucose concentrations improved the performance of mussel spat compared to the control, the best performing was a concentration of 1 mg mL−1 of dissolved glucose which enhanced daily spat growth 2.7 times that of the control live microalgal diet without glucose. Survival was high (i.e. >95%) for all treatments except for the highest experimental concentration of glucose, for which a concentration of 30 mg mL−1 resulted in mean mortality of 24%. Mussel spat supplemented with dissolved glucose accumulated up to 30% greater lipid and improved the carbohydrate content per mg g−1 of ash‐free dry weight as much as 3.5 times compared to those in the control treatment, indicating that they were in greater nutritional condition. This demonstration that dissolved glucose can be used to fuel growth by GLM spat at concentrations as low as 10 µg mL−1 suggests that other soluble nutrients may also act as a supplemental feed for cultured juvenile molluscs. Dissolved nutrients have the potential to improve the performance of spat in nursery systems while simultaneously reducing the reliance of cultured microalgae as a sole feed input. [ABSTRACT FROM AUTHOR]

In recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production. [ABSTRACT FROM AUTHOR]

Early mortality syndrome (EMS) or acute hepatopancreatic necrosis syndrome (AHPND) is an epizootic bacterial infection of shrimp that has had significant negative impact on the global shrimp aquaculture industry. This disease is largely attributed to pathogenic Vibrio parahaemolyticus EMS strains (VP‐EMS). Application of probiotics was examined for control of pathogenic VP‐EMS infections in Pacific white shrimp (Litopenaeus vannamei) under laboratory‐scale conditions. Two probiotic products, a single strain (O14VRQ) of Bacillus subtilis and a blend (Plus10) of five strains of Bacillus from four different species (Bacillus amyloliquifaciens, Bacillus megaterium, Bacillus brevis, and two distinct strains of Bacillus subtilis), were evaluated at various concentrations as feed additives (applied as a top coat on commercial feed) or dosed directly into the culture water. Two trials were conducted in which shrimp were fed either a control feed (no probiotics) or probiotic‐coated feed for 7 days prior to be being challenged with VP‐EMS. Shrimp were observed for clinical signs of disease and mortalities during the disease challenge study. These experiments demonstrated that while both Bacillus probiotic products were shown to significantly (p < 0.05) improve shrimp survival, the O14VRQ strain provided the most consistent protection across the trials in top‐coated feed. Overall, better efficacy was observed with probiotic‐coated feeds. Findings were directly and positively correlated with concentration for top‐coated and even more so for direct in‐tank applications. Collectively, these findings contribute to our understanding about how probiotic strains could be applied to enhance shrimp health in aquaculture. [ABSTRACT FROM AUTHOR]

Marine coastal resources are crucial to Tanzania's socio‐economic development and are a lifeline for the livelihoods and incomes of coastal communities. This study provides an overview of the coastal development of mariculture in mainland Tanzania and suggests future development strategies. The review article covers extensive reports available through field interviews, government policy documents, library literature searches and field work carried out by the authors. Despite the immense potential of mariculture to improve food security for localcommunities, its development has been uneven. Specifically only seaweed farming has advanced to commercial‐scale production. Other mariculture activities, such as finfish farming (e.g. milkfish, silver pompano), shellfish farming (e.g. prawn, mud crab and half‐pearl) and sea cucumber farming, are underdeveloped and confined to small‐scale operations. Locally consumed finfish, such as milkfish and pompano, have not attracted investors out of fear that the recovery of investment may not be achieved due to the low prices offered in the market. In this context, the sustainable use of coastal resources through mariculture becomes paramount to alleviating poverty and facilitating controlled migration from rural to urban. This comprehensive review explores the historical evolution and current status of mariculture initiatives in the coastal waters of mainland Tanzania, which presents a crucial aspect of the socio‐economic development of the nation. With declining global capture fisheries production and a growing demand for fish protein, Tanzania has strategically embraced mariculture as a viable alternative. The article traced the development of mariculture since the 1970s, highlighting past and current initiatives managed by government agencies, non‐government organizations and the private sector. Notable successes, such as seaweed culture, are highlighted along with the challenges that hinder the growth of marine farming activities. The review integrates insights from a comprehensive survey in coastal Tanzania, focusing on mariculture activities and collecting information on people who have stopped such practices, elucidating reasons for quitting. By consolidating experiences from past and present mariculture initiatives, this review provides valuable guidance for decision‐making towards promoting sustainable mariculture that supports coastal communities while preserving marine biodiversity. [ABSTRACT FROM AUTHOR]

Saprolegniosis, also called water mould, induces a cotton or wool‐like white growth on fish skin. It can kill fish at all stages of life, from eggs to adults. It is caused by oomycetes from the genus Saprolegnia and causes fish mortality and huge financial losses to fish farms and hatcheries. Saprolegnia species are endemic and ubiquitous in all freshwater habitats around the world. The exposing factors for saprolegniosis are still largely unknown, but stressors such as temperature shocks, poor water quality, handling and high fish density have been associated with outbreaks. For decades, malachite green was the most effective treatment against Saprolegnia infection, but it has been banned due to its carcinogenic and toxic effects. This has forced farmers to use alternative disinfection methods against Saprolegnia infection, such as hydrogen peroxide, formalin, Bronopol, NaCl, acetic acid and ozone, although many may have safety concerns or are impractical to use. This has led to the investigation of plant‐based compounds with antifungal and antibacterial properties against saprolegniosis. These include extracts of certain herbs, onion, garlic, extracts of the plant Chrysanthemum, essential oils of Eryngium campestre, Mentha piperita, Cuminum cyminum and Thymus linearis, which include a variety of phenolic compounds and fatty acids with antifungal properties. This review combines the current knowledge regarding the predisposing factors to Saprolegnia infections and current methods to prevent and treat them, including those under further research. Thus far, many compounds have been tested and studied, but an effective, suitable and safe compound to treat Saprolegnia infection remains to be found. [ABSTRACT FROM AUTHOR]

Nile tilapia (Oreochromis niloticus), native to Africa and the Levant, is an important species for both aquaculture and capture fisheries. Despite these attributes, Nile tilapia has been negatively impacted by anthropogenic activities ranging from overfishing and habitat destruction to translocations. These human‐mediated activities have threatened the genetic evolutionary integrity of native populations of Nile tilapia and congeneric species through admixture, demographic bottlenecks and introgressive hybridization. In this context, the genetic contrast between farmed/bred strains and wild Nile tilapia populations in the major lakes of Uganda remains understudied. Understanding the genetic structure of Nile tilapia populations in the major water bodies of Uganda (lakes Victoria, Kyoga, Edward, George, Albert and Nile River) is a key resource to guide selective breeding programmes, thus minimizing the effects of maladaptation under both aquaculture and natural stocks. Although the population genetics of Nile tilapia in Uganda's major lakes have been studied, this was based on limited sampling scope, especially in the wild, and the key information on the species could have been overlooked. We fill this knowledge gap by genotyping 756 Nile tilapia individuals from multiple populations for each major water body of Uganda using a panel of 34 microsatellite loci based on the microsatellite genotyping‐by‐sequencing (SSR‐GBS) technique. The results indicate two discrete gene pools/stocks: the Edward‐George system and the Albert‐Kyoga system‐Victoria. Evidence of loss of genetic diversity and admixture of some Nile tilapia stocks was found, most likely resulting from anthropogenic perturbations. This study contributes useful information key for understanding the potential Nile tilapia broodstock sources for selective breeding programmes, aimed at improving aquaculture production in Uganda. [ABSTRACT FROM AUTHOR]

This study examined the growth patterns of the spotted catfish, Arius maculatus (Thunberg, 1792) in the Thanlwin River Estuary throughout the analysis of standard lengths obtained from observed otolith data and back‐calculated data. Between April 2023 and January 2024, 516 fish ranging in standard lengths from 8.3 to 33 cm were collected. The annual deposition of annuli in otoliths was confirmed using the marginal increment ratio, with ages ranging from 2 to 9 years. The Dahl‐Lea back‐calculation method expanded the length at age data to 2472 records for ages 1–9 years. Growth was characterized using Von Bertalanffy growth curves, revealing the significant differences between the observed data (asymptotic length L∞ = 25.34 cm, growth coefficient K = 0.257 year−1 and growth performance index ϕ′ = 2.02) and the back‐calculated data (L∞ = 36.23 cm, K = 0.087 year−1 and ϕ′ = 2.21). The findings of the study suggested that the back‐calculated otolith data were more dependable for determining growth parameters compared to the observed otolith data. A. maculatus appears to exhibit slow growth characteristics, suggesting that the environmental conditions in the Thanlwin River Estuary may be deficient for this species. The insights gleaned from this research are crucial for guiding and shaping fishery management policies through informed advice and recommendations. [ABSTRACT FROM AUTHOR]

Offshore oil and gas platforms support abundant reef fish and are popular fishing sites for recreational anglers. However, the rapid decommissioning and removal of active platforms have decreased such fishing opportunities in the Gulf of Mexico, raising concerns about fisheries impacts. Conversely, planned offshore energy structures like wind turbines may offer similar habitats and fishing sites. To inform spatial planning for marine energy infrastructure in the context of recreational fisheries, we created models of fish communities associated with oil and gas platforms using existing abundance data. We employed Random Forest analysis to predict the presence‐absence and abundance of Red Snapper (Lutjanus campechanus) and Greater Amberjack (Seriola dumerili) at platforms using 47 environmental and platform variables. Nonmetric multidimensional scaling on Bray−Curtis dissimilarities explored fish species composition among 37 species. Results showed variability in Red Snapper and Greater Amberjack incidence/abundance from shore to shelf‐edge, not attributed to surrounding habitat or climatological oceanographic variables. Incidence models were more robust than abundance models. Fish species composition was significantly influenced by location gradient, with less impact from other habitat features. Our findings guide selecting areas for artificial structures to enhance angler opportunities and maintain fish diversity, but identifying the drivers of finer scale abundance variation will require further sampling. [ABSTRACT FROM AUTHOR]

Sentiment analysis, a form of data analytics, utilises information from online discussions, reviews, and social media posts to assess consumer sentiments. This study utilised data collected from social media using online listening procedures to assess online sentiments on oysters from January 2019 through December 2022. The analysis utilises machine learning algorithms to extract consumer sentiments, opinions, and demands from online chatter from different online domains. The online sentiments are determined as positive, negative, or neutral based on their word choice, tone, and context. The information provided gives insights into perception, which is valuable information for oyster producers, seafood industry stakeholders, and marketers to identify consumer preferences and formulate appropriate strategies accordingly. The results suggest that while farmed oysters are gaining popularity, there are still some concerns and criticisms around the industry. Positive words associated with mentions of oysters in general include 'great', 'love', 'delicious', 'enjoyed', and 'oyster bar', while negative words associated with oysters include 'water', 'raw oyster', 'bad', and 'not eat'. The overall percentage net sentiment associated with all oysters in the United States is positive at 63%. The net sentiment associated with wild oysters is positive, at 51%, and that of farmed oysters is 58%. The oyster industry could invest more in public education, sustainability, and water‐cleaning initiatives to improve its image. Utilising social media to monitor and shape public perception can help the industry address concerns and enhance oyster‐related sentiments, offering valuable insights for marketing and sales strategies. [ABSTRACT FROM AUTHOR]

This study explored the potential of three local microalgal isolates as feed for oyster larvae in laboratory‐rearing experiments, towards the optimisation of seed production of Crassostrea tulipa to support its large‐scale farming along the West African coast. Three species of local microalgae—Rhodomonas sp., Nannochloropsis sp. and Pseudanabaena sp.—were isolated from waters off the coast of Ghana, West Africa, following a serial dilution technique. The growth performance of the isolates was assessed in the laboratory through daily estimation of cell density until the stationary phase was observed. Characterisation of the microalgal isolates was carried out by estimation of their biovolume, carbon content and energy content. Biovolumes of the microalgae were calculated from the estimated equivalent spherical diameters using proposed geometric shapes and formulae. Carbon weight and carbon energy content were subsequently calculated using derived conversions. The three microalgal isolates showed potential for large‐scale cultivation in the laboratory with marked differences in daily increases in cell densities. Nannochloropsis sp. and Rhodomonas sp. recorded the highest and the lowest peak densities of 2.4 × 105 and 1.5 × 105 cell mL−1, respectively, from an initial inoculating cell density of 1.05 × 105 cell mL−1. The estimated mean biovolumes of Rhodomonas sp., Nannochloropsis sp. and Pseudanabaena sp. were 238.9, 8.182 and 42.42 µm3, respectively, and the corresponding derived carbon energy contents were 1.7 × 10−6, 7.13 × 10−8 and 1.05 × 10−7 J, respectively. Results from a laboratory rearing experiment indicated that the individual microalgal isolates supported the growth and survival of oyster larvae at different scales, but a mixed diet of the three promoted superior growth and survival of C. tulipa larvae. The three local microalgal isolates‐ Rhodomonas sp., Nannochloropsis sp., and Pseudanabaena sp.‐ were well adapted to laboratory culture conditions, and the observed differences in growth and survival of the oyster larvae fed on these algal diets could be due to the differences in diet properties and biochemical compositions of the different species. A combination of the three algal diets, however, provided complementaery nutrients for the optimal growth and survival of C. tulipa larvae. The outcome of this study shows that local microalgal isolates have the potential to support hatchery rearing of C. tulipa, which is essential for the development of commercial mangrove oyster aquaculture in West Africa. [ABSTRACT FROM AUTHOR]

Aquaculture is the world's fastest‐growing food‐producing sector, making it a significant contributor to food and nutrition security for the globally growing human population. Nevertheless, its long‐term growth is limited by the effects of climate change. Aquaculture in Sub‐Saharan Africa (SSA), which is dominated by small‐scale fish farming, is increasingly threatened by climate change, which has a substantial influence on its productivity and scalability. In this context, the present research looks at the socio‐economic consequences of climate change on small‐scale fish producers in SSA, as well as potential adaptation techniques to the effects of climate change. A clear understanding of these socio‐economic repercussions of climate change is critical for developing effective strategies to reduce future impacts and safeguard aquaculture‐based livelihoods. Furthermore, understanding the socio‐economic consequences of climate change on communities dependent on aquaculture is important for advising policymakers and decision‐makers on formulating and implementing policies that sustain aquaculture production amidst the climate change crisis. This article suggests various adaptation strategies to increase resilience to climate change, including diversification of livelihoods and species, use and incorporation of local and indigenous knowledge, shifting to aquaculture species less vulnerable to changing climatic conditions, capacity building through aquaculture insurance schemes, continued fish supply from capture fisheries, and consolidation of equity and human rights concerns. These adaptive methods, when combined, have the potential to enhance outcomes for populations who are more susceptible owing to their unstable socio‐economic conditions. [ABSTRACT FROM AUTHOR]

The lake cisco (Coregonus artedi) is not often caught by recreational anglers in open‐water in western Canada but becomes a common component of catch‐and‐release ice fisheries in the winter. Little is known about the composition of recreational cisco fisheries or factors that affect the success of winter catch and release. We examined the size and body condition of 555 cisco caught by anglers in four interconnected lakes in southern Saskatchewan, Canada. We also examined the influence of length on the probability of hooking injuries and determined the age of a subset of angled fish. Cisco caught by anglers ranged in total length from 24 to 48 cm and 110 to 1370 g mass; however, 60.2% of cisco caught ranged from 37 to 40 cm and 470 to 560 g. The scale ages of cisco caught by anglers ranged from 4 to 10 years, with the most common ages caught being 6–8 years; however, scales likely underestimated age beginning around 8 years. Overall, cisco from our four study lakes had lower body conditions compared to Lake Superior populations based on standard weight comparisons. The length, mass, age and body condition of cisco caught by anglers varied significantly among our four study lakes, following a west‐to‐east productivity gradient. Of the 555 cisco assessed, 54 (9.7%) experienced gill bleeding and 21 (3.8%) had other visible hooking injuries. Longer cisco had a significantly increased probability of gill bleeding, but length did not affect the probability of other injuries. Cisco are relatively slow growing in our study area and warrant more consideration from a catch‐and‐release angling perspective. [ABSTRACT FROM AUTHOR]

Microalgae offer a sustainable source of omega − 3 fatty acids that can replace fish oil in aquafeeds, but the nutritional benefits are not always clear, particularly when microalgae are used as complete oil replacements in starter feeds. We compared the survival, growth, omega − 3 deposition and composition of the gut microbiota of juvenile mixed‐sex Nile tilapia (Oreochromis niloticus) that had been fed over a 3‐month period on six isonitrogenous, isolipidic and isocaloric aquafeeds that varied only on the contribution of fish oil, soya oil and microalgae (Schizochytrium) oil as lipid sources. Survival was not affected by diet, but fish fed a diet where the entire oil component (5%) was replaced by microalgae oil grew twice as fast as fish fed plant oil or a mixture of plant and fish oil. Dietary omega − 3 content was strongly correlated with omega − 3 deposition in the fish fillet. Complete replacement of fish oil by plant oil caused a significant decrease in the abundance of Peptostreptococcaceae and an increase in the abundance of Aeromonadaceae which is often associated with an inflammatory response in the fish gut. In contrast, when fish and soya oil in the reference diet were replaced by 100% microalgae oil, an increase in Mycobacteriaceae was observed. Our study indicates that Schizochytrium oil can be used to improve the growth of Nile tilapia and increase its omega − 3 content without any of the detrimental effects on the gut microbiome typically associated with some plant oil replacements. [ABSTRACT FROM AUTHOR]

An editorial is presented which expresses the views on the progress and future direction of the journal "Aquaculture, Fish and Fisheries" as it supports the blue revolution. Topics include the journal's achievements in promoting global research on aquaculture and fisheries, the introduction of new initiatives for early-career scientists, and the focus on addressing challenges like climate change, pollution, and sustainability in aquatic ecosystems.

This review was aimed to summarize the extent and causes of fish post‐harvest losses (FPHLs) in Sub‐Saharan African (SSA) countries and suggests the necessary intervention measures to narrow the gap between demand and supply. Globally, an estimate of 10–12 million tons of fish is lost per year. FPHLs in SSA are higher than those in other parts of the world. In SSA, the values of fisheries are estimated at 24 billion USD, 1.26% of the GDP of all the African countries and 6% of agriculture GDP. The vast majority of FPHLs in SSA occur at the production (39%), handling (36%), distribution (13%), processing (7%) and consumption (5%). The major factors that cause FPHLs in SSA were long time spent in hauling of fishing gears, spoilage, size discrimination, species preferences, operational losses, animal predation, poor handling practices, lengthy duration of fishing cycle, failure to use ice, lack of storage facilities, lack of transportation and insect infestation. FPHLs amount one third of total production and financial losses of 2–5 billion USD in SSA countries. Furthermore, volarization of fish waste and converting waste into useful substances is a promising approach to reduce fish waste. It can be recommended that improving fish production, live fish handling, processing, preserving, and marketing in SSA could narrow the gap between fish demand and supply. [ABSTRACT FROM AUTHOR]

Bluespotted seabream Pagrus caeruleostictus, a member of the family Sparidae, is one of the high‐priced seabream species in Ghana. Although the fish has been exploited in the Gulf of Guinea for over hundreds of years, there is scanty information on the state of the fish stock. Hence, we sought to investigate the exploitation status and aspects of the reproductive biology of the species by collecting monthly length and weight data for 18 months (February 2016 to July 2017). These data were fitted to growth and mortality models. The sexual maturity, fecundity and spawning seasons were also determined within the same period. The growth model of the fish revealed that the asymptotic length (L∞) and growth coefficient (K) values determined were 52.7 cm (total length) and 0.52 year−1, respectively. The mortality models also showed that the fishing mortality (F) of the fish was 2.20 year−1, whereas its natural mortality (M) was 0.83 year−1, with F/M > 0.5 indicating that the fish is over‐exploited. The lengths at first sexual maturity (Lm) of the males and females were 36.2 and 28.0 cm, respectively. Pagrus caeruleostictus, which was found to be highly fecund, had two spawning periods in a year, occurring in September and March, both with unimodal ova diameter frequency distributions. Based on these findings, we recommend that catch limits and other appropriate management measures (e.g. temporal and spatial closures) should be prescribed for the seabream fishery in the Gulf of Guinea to ensure the sustainability of the fishery. [ABSTRACT FROM AUTHOR]

Gizzard Shad Dorosoma cepedianum have been introduced into Western South Dakota reservoirs and shown to improve the growth and size structure of sportfish, particularly Walleye Sander vitreus. Black Crappies Pomoxis nigromaculatus are a popular sportfish in these reservoirs, but influences Gizzard Shad have on these populations have not been well documented. We used 10 years of annual sampling data to evaluate changes in Black Crappie population characteristics (i.e. recruitment, growth, size structure and condition) in four Western South Dakota reservoirs after Gizzard Shad were introduced. We also compared Black Crappie population characteristics after shad introductions to populations in three reservoirs never having shad. We found Black Crappie populations in Western South Dakota reservoirs are characterized by variable recruitment, generally experiencing some level of recruitment failure. Reservoirs with Gizzard Shad showed greater mean length‐at‐age and higher proportional size distributions (PSD and PSD‐P) for Black Crappie after the shad introductions and higher values than observed in reservoirs never having shad. We found no meaningful differences in abundance, and mean condition of Black Crappie populations whether Gizzard Shad were present or not. The addition of Gizzard Shad did not appear to negatively affect Black Crappie populations but rather improved crappie size structure. Our results indicate that introductions of Gizzard Shad are a viable management option for producing quality Black Crappie fisheries in Western South Dakota reservoirs. [ABSTRACT FROM AUTHOR]

Aquaculture of Atlantic salmon Salmo salar is in transition to precision fish farming and digitalization. As it is easier, cheaper and safer to study a digital replica than the system itself, a model of the fish can potentially improve monitoring and prediction of facilities and operations and replace live fish in many what‐if experiments. Regulators, consumers and voters also want insight into how it is like to be a salmon in aquaculture. However, such information is credible only if natural physiology and behaviour of the living fish is adequately represented. To be able to predict salmon behaviour in unfamiliar, confusing and stressful situations, the modeller must aim for a sufficiently realistic behavioural model based on the animal's proximate robustness mechanisms. We review the knowledge status and algorithms for how evolution has formed fish to control decisions and set priorities for behaviour and ontogeny. Teleost body control is through genes, hormones, nerves, muscles, sensing, cognition and behaviour, the latter being agentic, predictive and subjective, also in a man‐made environment. These are the challenges when constructing the digital salmon. This perspective is also useful for modelling other domesticated and wild animals in Anthropocene environments.Modern digitized aquaculture requires a digital twin of the Atlantic salmon Salmo salar: a realistic simulation replica of the fish physiology, life history and behaviour. It will be able to predict fish behavior in unfamiliar, confusing, and stressful situations based on proximate robustness mechanisms. We review the current knowledge on how evolution has shaped fish to set priorities and control decisions for adaptive behavior and ontogeny, and survey models and component algorithms for a biology‐based digital twin of the salmon. [ABSTRACT FROM AUTHOR]

Information on yellow perch Perca flavescens population dynamics and responses to various abiotic and biotic factors in oligotrophic, north‐temperate inland lakes is limited. Water level fluctuations are known to influence available habitat and biological communities within the littoral zones of lakes, yet research is lacking for yellow perch in Wisconsin. The goal of our study was to characterize yellow perch population‐level responses to natural water level fluctuations in four northern Wisconsin lakes using a 39‐year time series. On average, increasing water level periods correlated with lower mean fyke net and gill net relative abundances (catch‐per‐unit‐effort), though generally not statistically significant. Yellow perch mean relative weight varied among lakes and was significantly greater during increasing water level periods for all lakes except one. The lack of statistically significant findings potentially suggests a buffering mechanism of north‐temperate oligotrophic lakes due to their small surface area to volume ratios, relative lack of nutrients, and(or) littoral structural habitat compared to other systems (e.g., shallow eutrophic lakes). Our results suggest that natural water level fluctuations may not be an environmental concern for yellow perch populations in some north‐temperate oligotrophic inland lakes. [ABSTRACT FROM AUTHOR]

Lake Victoria is the second‐largest freshwater lake in the world, with a surface area of 68,800 km2. The lake is rich in natural resources that are essential to the local economy and livelihoods. However, International Union for Conservation of Nature (IUCN) ranks 76% of freshwater species endemic to the Lake Victoria Basin as threatened with extinction. The biodiversity richness of the lake is still diminishing, and the risk of species extinction is increasing. Many species are yet to be identified, and thus the number of species threatened with extinction exceeds what is currently known. Furthermore, the lake is home to species that are found nowhere else on the planet, but its protection is never given the attention it needs. Genetic diversity loss is harmful to future populations and influences sustainability of the ecosystem. The decline in Lake Victoria's biodiversity is primarily attributed to various pressing issues, including water pollution, invasive species, climate change, overexploitation and the challenges stemming from high human population density. These problems are exacerbated by inadequate regulatory enforcement and a lack of comprehensive data and information to inform and guide conservation efforts. If these factors are not addressed, they may have a detrimental impact on Lake Biodiversity. This article aims to document the main threats to aquatic biodiversity as well as potential management strategies for preventing further losses of the aquatic biodiversity in Lake Victoria. The study recommends reviewing, bolstering and reinforcing the rules and regulations governing the extraction, accessibility and discharge of nutrients into the lake. The national governments should work with local governments, non‐governmental organizations and local people to safeguard and conserve the lake's biodiversity. The national governments of the riparian nations should also reserve funds each fiscal year specifically for research that would inform effective management measures to prevent further losses of the lake's biodiversity. [ABSTRACT FROM AUTHOR]

Rainbow trout (Oncorhynchus mykiss) is among the most widely translocated fish species in the world. The current study evaluated the spawning interactions between naturalized and wild rainbow trout from two high‐altitude second‐order streams, in Kenya. Data on total length, weight, condition factor, fecundity, fertilization, egg diameter and fry survival were collected on spawning rainbow trout between March and December 2021. Length–weight relationship showed parabolic equations as W = 0.0144L2.900, W = 0.0069L3.0285 and W = 0.00027L3.175 for wild fish stock, hatchery‐reared and wild × hatchery‐reared rainbow trout, respectively. Total fecundity differed significantly among the hatchery‐reared, wild fish and the cross of the two (p < 0.05). The fertilization rate showed significant differences (p < 0.05), with no discernable difference observed between the hatchery‐reared and crossed (wild × hatchery‐reared). There was a positive correlation among the total fecundity to female egg weight, female body weight, fertilization rate and eyed egg survival in all the populations. Relative fecundity was significantly different among the three groups of fish (p < 0.05), but the differences between the hatchery and the crossed (wild × hatchery‐reared) fish showed no significant differences. We recommend the use of crossed (wild × hatchery‐reared) populations for fry production for use in aquaculture as they presented the highest fecundity and gave the best outcome of fry with high survival. [ABSTRACT FROM AUTHOR]

Stagnating capture fisheries and increasing fish protein demand necessitate aquaculture production to bridge the gap. Lake Victoria is a potential water body for increasing fish production through cage farming. The sustainability of Lake Victoria for cage farming depends on timely and holistic site selection. However, current site selection methods involve complex, resource‐intensive field surveys that lack a holistic approach to integrate multiple factors. Accordingly, information regarding suitable sites for sustainable fish cage farming in Lake Victoria remains scarce. In this study, a transparent geographic information systems (GIS) and multicriteria evaluation (MCE) here after reffered to as GIS‐MCE was used to reveal potential sites to be permitted or avoided during cage aquaculture development in the Mwanza Gulf of Lake Victoria (Tanzania). Our analysis involved weighting and integration of sub‐models representing ecologically sensitive areas, physical environment, and socio‐economic and water quality variables into a single spatial model portraying different site suitability levels in the Mwanza Gulf. The results indicated that the sub‐models identified relatively larger suitable and most suitable sites compared to the overall model. No site maintained its status across all sub‐models. The overall model designated a small area (5.10 km2 or 1.52%) as the most suitable site, with 24.20 km2 (7.44%) as suitable, 64.47 km2 (19.82%) as less suitable, and 42.63 km2 (13.12%) as unsuitable for cage fish farming. The remaining area (188.84 km2 or 58.06%) was a constrained site to be avoided during cage aquaculture development. Taken together, the individual sub‐models are ineffective in designating potential sites for fish cage culture and thus should not be used solely. The GIS‐MCE general model provides a fast and timely method for identifying potential sites for cage farming in Lake Victoria. Fish farmers and managers should use the GIS‐MCE overall model in inland waters to facilitate site selection for complying with licensing requirements and decrease field extensive surveys. [ABSTRACT FROM AUTHOR]

Aquaculture developmental plans represent a nation's determination for self‐reliance on domestic fish production through resilient aquaculture. This study reviewed the 2012 Ghana National Aquaculture Development Plan (GNADP) and sought inputs from industry stakeholders to inform GNADP 2023 using the ecosystem approach to aquaculture (EAA). In furtherance of this, we also investigated the justifications for antibiotic treatments including the assessment of the sector that is supposed to regulate aquaculture growth. The findings suggest that GNADP 2023 must be strategized to address industry sustainability bottlenecks identified as input availability and quality, permitting, regulation and enforcement, financing schemes and technical expertise. In terms of technical expertise, the inclusion of women in aquaculture can diversify the skill sets for the improvement of capacity and competence in good aquaculture practices and fish health management. Sector partnerships can aid in leveraging the expertise and resources among sectors to address persistent industry issues. The justifications for antibiotic treatments are disease management, prophylactics, antibiotic availability, application, and effectiveness, capacity and competence, including regulation and enforcement. This also comprised the sense of ownership and responsibility as farmers feel they must safeguard their investment. It is therefore important for farmers to pursue preventative aquaculture biosecurity measures. The government sector was selected predominantly to regulate aquaculture growth. We however recommended a participatory approach as this could facilitate peer regulation to enhance the regulation and enforcement of aquaculture regulations. The findings in this study are worth considering as it pioneers the adoption of the EAA framework for aquaculture developmental planning in Ghana. [ABSTRACT FROM AUTHOR]

A novel general model has been developed to fit biomass growth data of coleoid cephalopods as a function of time and temperature from hatching to maximum size in a single curve. This model has been obtained formally from a formulation of product‐integral, solves the discontinuity problem present in two‐phase growth models and describes both asymptotic and non‐asymptotic growth. Within the usual temperature range in which the organism develops, our model describes a non‐asymptotic growth achieving a good fit with the experimental data (R2>0.98)$({{R^2} > 0.98})$. In particular, the model provides precise calculation of the time k at which the growth curve inflection occurs, time μ1 at which sexual maturity begins and time μ2 at which the maximum size is reached. When the model was parameterized as a function of temperature, it corroborated different results on Octopus maya fitness, in particular, 25.7°C was obtained as the temperature that generates the highest average growth rate and 21.7°C as the temperature with the highest biomass accumulation over time. This result confirms that the temperature range of 22–26°C is suitable for the growth of O. maya and shows that the developed model can be a useful tool for aquaculture. [ABSTRACT FROM AUTHOR]

This study examined factors affecting fishers' interest in participating in human immunodeficiency virus (HIV) testing at Elmina fishing community in the Central Region of Ghana. The study additionally inquired of respondents if they would be willing to submit to an HIV test and, if so, if they knew where to go for the test. The study also looked at the barriers that prevented fishers from getting tested for HIV. A cross‐sectional convergent parallel mixed‐method design was used to examine 385 fishers who were at least 18 years old and engaged in any form of fishing activity. Only about 9% of respondents reported having ever tested for HIV. Although the overall testing rate was low, the results indicate a higher testing rate in females than among males. Multivariate analysis shows that sex, age and type of fishing occupation are significant predictors of willingness to test for HIV among the study participants. Even though many people in the study location may know where to get tested for HIV, they are unwilling to do so. Many residents of the research area may be aware of where to get tested for HIV, but they are unwilling to go. This suggests a lack of enthusiasm due to misunderstandings and misconceptions about what HIV testing uptake entails. Additionally, stigmatization is a significant barrier to the acceptance of HIV testing in the study area and needs to be reduced by increased education. [ABSTRACT FROM AUTHOR]

Although small‐scale fisheries and aquaculture provide opportunities to increase fish yield to supplement rural food and income, they remain undeveloped in Ghana. To contribute towards the development of the sectors, this study sought to assess the biology and ecology of Oreochromis niloticus and Sarotherodon melanotheron in the Brimsu reservoir to provide the requisite information for their management. From the results, mean temperature, dissolved oxygen, pH and transparency of the reservoir were 30.03 ± 0.27°C, 3.78 ± 0.38 mg/L, 8.30 ± 0.21 and 69.79 ± 1.76 cm, respectively. S. melanotheron had a sex ratio of 1:1.36; with mean condition factors of 2.177 ± 0.089 and 2.06 ± 0.029 (p = 0.08) for males and females, respectively. The sex ratio of O. niloticus was 1.45: 1; with mean condition factors of 2.208 ± 0.012 and 2.257 ± 0.014 (p = 0.07) for males and females, respectively. Both species exhibited positive allometric growth with no significant differences between the condition factors for males and females. In addition, there was no significant difference between the sex ratios for S. melanotheron but the number of males of O. niloticus was significantly higher than the females (p ˂ 0.05). Size at sexual maturity (Lm), form factor (a3.0), growth coefficient (K), asymptotic length (L∞) and natural mortality (M) of S. melanotheron were 18.00 cm, 0.020, 0.42 year−1, 30.32 cm and 0.64 year−1, respectively. For O. niloticus Lm, a3.0, K, L∞ and M were 18.57 cm, 0.0223, 0.26 year−1, 38.42 cm and 0.41 year−1, respectively. However, the catch per unit effort for O. niloticus was higher than that of S. melanotheron throughout the study period. The conditions of the reservoir were favourable for the growth of these cichlids. It is recommended that measures should be put in place for the sustainable management and exploitation of fish stocks. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the water quality, growth performance, body composition, length–weight relationship, condition factors and benefit–cost analysis of giant freshwater prawn (Macrobrachium rosenbergii) cultured with biofloc system in pond conditions. The experiment was conducted in twelve (12) experimental ponds, each measuring 240 m2. The control group was cultured without any biofloc (T1), and biofloc‐based three treatments were biofloc with 100% feed (T2), biofloc with 90% feed (T3) and biofloc with 80% feed (T4). The biofloc‐based treatments showed significantly higher floc volume, total suspended solids, total heterotrophic bacteria and plankton density than the control (p < 0.05). All the growth parameters were significantly higher in biofloc‐based treatments (T2, T3 and T4) than in the control (T1). The lowest feed conversion ratio was found lowest in T4 (1.40 ± 0.02) and highest in T1 (2.13 ± 0.04), which was significantly different among the treatments (p < 0.05). The significantly highest production was obtained 939.02 ± 6.61 kg/ha in T2, and the lowest was 779.67 ± 7.50 kg/ha in T1. The length–weight relationship indicated positive allometric growth in all treatments. The condition factor ranged from 0.95 to 1.07, showing that the prawns were in good health throughout all treatments. The results of the present study indicated that M. rosenbergii can adapt to a biofloc‐based aquaculture system, and the conventional feeding rations can be reduced up to 20% without affecting the growth and production. [ABSTRACT FROM AUTHOR]

Fisheries studies concerning the related impacts of fishing on the aquatic environment have mostly dealt with industrial fisheries. Concerted large‐scale exploitation can lead to stock declines and potentially species extinction. Hydrocynus vittatus is a piscivore and popular recreational fish species that can grow up to 70 cm fork length and weigh up to 15 kg. Hydrocynus vittatus is also a fish of importance in Lake Kariba as local communities along lake shorelines depend on it for both income and food. There is an insufficient understanding of the impacts of artisanal fishing on tigerfish, H. vittatus population parameters and reproductive biology in Lake Kariba. Hence, this study investigated life history traits and population dynamics of H. vittatus in the Ume Basin of Lake Kariba, north‐eastern Zimbabwe. Scales were used to estimate the age of tigerfish and the Bertalanffy growth curve used to estimate the growth parameters. A gonadal reproductive stage determination index was used to determine sexual maturity and the logistic growth curve was used to estimate size at 50% sexual maturity (L50). Using the gonadal maturation index, the L50 for males was estimated ranging between 120 and 149 mm. On the other hand, L50 reached between 250 and 299 mm in females. Females had a higher average mean length (335 mm), compared to that of males (289 mm). The length‐at‐age data from scales had relatively few outliers and moderate scatter. Parameters for the von Bertalanffy growth curve were (L‐infinity = 641.5, k = 0.517, t0 = 3.07). This study highlighted the negative impacts (male‐biased sex ratio and small size at maturity) that artisanal gillnet fishing has on the population structure and reproductive potential of tigerfish in the Ume Basin of Lake Kariba. These impacts are a direct result of both legal and illegal fishing activities of the fishers operating in the Ume Basin and based at Musamba Fishing Camp. There is, therefore, an urgent need for the regulatory authority, the Matusadona Conservation Trust, to engage the fishers in developing long‐term strategies to reverse the observed unhealthy population status and allow the tigerfish stock to replenish itself. [ABSTRACT FROM AUTHOR]

Fisheries systems face enormous pressures from increased fish demand, decreased fish catches, and an ageing fishing population. As a case study, we investigate how climate change stressors, capacity‐building opportunities, and the introduction of climate‐smart innovations, tools and information may influence youths' succession decisions in small‐scale fisheries (SSF). We collected empirical data from a survey with the children of SSF actors to identify the factors promoting or hindering succession in fish harvesting activities through a simple random sampling of 415 youths in six fishing communities in Cameroon. The probit model results revealed that youth participation and succession decisions are positively influenced by their education, nationality, that is, being a migrant, desire to be employed full‐time in fisheries‐related activities, climate‐smart innovations, tools and information, and capacity‐building opportunities. Increasing temperatures and uncertainty in fish availability due to climate change negatively influence their succession decisions. We find that parents do not encourage their children to participate in SSF due to climate change impacts, which are reducing fish catch and due to a lack of suitable climate‐resilient innovations and capacity‐building opportunities. The study provides evidence that interventions that create an enabling environment for youths' participation in fisheries‐related activities are important to secure the future of SSF in Cameroon. [ABSTRACT FROM AUTHOR]

An editorial is presented which expresses the views on the continued development of the journal "Aquaculture, Fish and Fisheries" as it celebrates its third anniversary. Topics include the introduction of a new article type called Underwater Notes, efforts to improve the author experience, and the journal's commitment to covering significant environmental, sustainable, and socioeconomic themes in aquaculture and fisheries science.