The current study was carried out to examine the effects of four different experimental salinities (T1 = 0‰, T2 = 5‰, T3 = 10‰, and T4 = 15‰) on growth, water quality, proximate composition, total bacterial (TB), and hemocyte counts of white leg shrimp (Litopenaeus vannamei) and giant prawn (Macrobrachium rosenbergii) in biofloc based nursery bi‐culture system for 6 weeks. A total of 12 cylindrical plastic tanks (125 L) filled up 100 L water for rearing L. vannamei and M. rosenbergii post‐larvae (PLs) at an equal ratio: (50 L. vannamei: 50 M. rosenbergii). At the end of the experiment, for L. vannamei, the significantly higher (p < 0.05) growth rate was recorded in T4 (15‰) compared to the other treatments. For M. rosenbergii, a significantly higher (p < 0.05) growth rate was recorded in T2 (5‰) than in other treatments. Similar to growth, the best (p < 0.05) feed conversion ratio (FCR) for ‐L. vannamei was found at T4 (15‰) while it was at T2 (5‰) forM. rosenbergii. Gross return, net profit, and benefit–cost ratio (BCR) analysis revealed higher profit T4 (15‰) than T3 (10‰), T2 (5‰), and T1 (0‰). TB counts were found to be significantly greater (p < 0.05) in T4 than other treatments. Hemocyte counts for L. vannamei were significantly higher (p < 0.05) in T4 (15‰) than T3 (10‰), T2 (5‰), and T1 (0‰) and for M. rosenbergii hemocyte was significantly higher (p < 0.05) in T1 (0‰) than T2 (5 ‰), T3 (10 ‰), and T4 (15‰). Therefore, it can be suggested that 15‰ salinity will be the best condition for the nursery bi‐culture of white leg shrimp (L. vannamei) and giant prawn (M. rosenbergii) in the biofloc system.

Rainbow trout farming in Kenya remains an underdeveloped yet high‐potential sector within the country’s aquaculture industry, despite the availability of suitable ecological conditions in high‐altitude regions. This review critically examines the historical evolution, current status, challenges, and future prospects of rainbow trout farming in Kenya, drawing on comparative insights from leading rainbow trout‐producing nations. Introduced during the early 20th century for sport fishing, rainbow trout aquaculture has gradually transitioned into a commercial enterprise, albeit at a limited scale. Despite increasing consumer demand and premium market value, the industry faces significant constraints, including inadequate seed supply, high feed costs, climate variability, weak market infrastructure, regulatory inefficiencies, and limited research and extension support. The reliance on imported fingerlings and feeds exacerbates production costs, making the sector less competitive. Furthermore, climate change‐induced water scarcity and rising water temperatures threaten cold‐water aquaculture, necessitating urgent adaptation strategies. Drawing lessons from global industry leaders, such as Norway, Chile, and India, this review highlights strategic interventions for optimizing Kenya’s rainbow trout farming industry, including strengthening hatchery systems, developing cost‐effective local feed, enhancing climate‐smart farming technologies, and establishing structured market linkages. Policy reforms and increased investment in research, extension services, and environmental conservation are crucial for unlocking the untapped potential of rainbow trout aquaculture. If effectively harnessed, rainbow trout farming could contribute significantly to national fish production, rural livelihoods, and economic growth while promoting environmental sustainability.

Hyaluronic acid (HA) is a versatile polysaccharide with a broad range of biological, pharmacological, and therapeutic applications due to its anti‐inflammatory properties, low immunogenicity, natural breakdown, compatibility with live tissue, and capacity to promote cell growth and specialization. However, the potential negative effects of HA on aquatic ecosystems, especially fish, have not been fully investigated. This study examines for the first time the potential physiological, immunological, and histological effects of HA in African catfish, as well as the long‐term implications following recovery. Four groups, totaling 24 African catfish in triplicate, were subjected to varying concentrations of HA (500–100,000 µg/L) over a 15‐day exposure period, followed by a 15‐day recuperation phase, leading to physiological changes dependent on the dosage. The electrolyte levels in the plasma and the equilibrium of redox processes were significantly upset by exposure to HÀ. Fish exposed to high HA concentrations displayed dose‐dependent declines in immunological function and antioxidant enzymes. Only the fish exposed to modest doses of HA showed complete recovery when compared to the control fish, indicating that exposure to HA resulted in irreversible alterations. The histological investigations showed a number of dosage‐dependent pathological alterations in the renal and hepatic tissues, including perivascular and peritubular fibrosis, tubular necrosis, and vacuolar degeneration. The degree of these alterations varied according to the dose. Concluding that fish may have irreversible alterations as a result of high acidity. The present study provides a fundamental understanding of the detrimental effects of HA on fish. To fully evaluate the potential dangers associated with HA exposure and its long‐term effects on aquatic life, more research is needed.

Aquaculture is a growing industry, but current practices and raw material utilization must be reviewed to ensure a resilient and sustainable development. In this sense, the transition from a linear economy (take, make, dispose) to a circular one (renew, remake) is accelerating. The biofloc technology (BFT) is a relatively new cultivation system that can be adopted to accomplish more sustainable aquaculture and circularity goals. This document discusses BFT and its association with the circular economy (CE), the current aquaculture challenges, and the role of BFT in overcoming those challenges. This manuscript adopts Cramer’s 10 R’s and Muscat et al.’s five P’s frameworks to understand whether a functioning BFT and its key compartments (i.e., feed, environment, water, system, and microbials) align with CE’s core principles. In addition, the present work provides and discusses relevant insights regarding the further (industry and academia) application of CE approaches, especially in a biofloc‐based farming context. According to the findings and connections with Cramer’s 10 R’s and Muscat et al.’s five P’s frameworks, BFT encompasses several transitioning steps into circularity and could play a crucial role toward a more sustainable aquaculture in line with the CE.

Inland aquaculture using underground brackish water is a promising method to alleviate pressure on freshwater resources. Nile tilapia stains utilized for commercial production can also tolerate low‐salinity brackish water. Therefore, the goal of this study was to compare the reproductive performance of females and males of five genetically different Nile tilapia strains under brackish water cultivation. The GIFT, Big Nin, Mag Nin, Thai red, and Taiwanese red strains, with initial mean weights of 165.5 ± 18.3, 157.8 ± 26.1, 157.1 ± 27.6, 163.3 ± 26.3, and 175.9 ± 27.3 g (±standard deviation), respectively, were used. The fish were individually tagged and each strain was maintained in 8 m2 rectangular concert tanks for 120 days (two fish/m2). The fish were fed at 1.5% of their body weight twice a day with a commercial diet (42% crude protein) at 29.0 ± 0.5°C. The highest female body weight was obtained in the red color strains (Thai and Taiwanese strains) compared to Big Nin strain (p < 0.05) and it was not significantly different in other black tilapia strains. The results of the reproductive indices including spawning frequency and cycles, fertilization and hatching rates, and hepatosomatic index indicated no significant differences among the strains (p > 0.05). However, Mag Nin strain exhibited higher working and relative fecundity values than GIFT strain. A longer reproduction cycle was recorded in GIFT strain than Taiwanese red strain (p < 0.05). In terms of egg quality, no significant differences were obtained among the tilapia strains. A higher sperm motility was recorded in GIFT strain than Mag Nin strain, while other groups showed no significant differences. Overall, GIFT strain demonstrated superior values of sperm motility and reproduction cycles, while Mg Nin strain showed high working and relative fecundity values. The results of the reproductive performance of each genetically improved Nile tilapia strain will be discussed by fish farmers upon their specific environmental conditions and production goals.

Atlantic salmon production constitutes a growing industry in the United States and is largely reliant upon cage‐culture in which fish are cultivated within enclosed nets or pens in environmental settings that are prone to natural variation. Temperature fluctuation in particular can substantially inhibit or accelerate production. Here we investigate the larval respiratory capacity (respiratory Q10) among pedigreed families of Atlantic salmon (Salmo salar) spawned in a hatchery facility exposed to acute thermal stress. Individual larvae from full‐sibling families were incubated at three temperatures along a 10°C thermal gradient (6, 12, and 16°C) in calibrated respiration chambers and linear declines in oxygen content were used to determine individual respiration rates and family‐based Q10. Metabolites from the tricarboxylic acid (TCA) pathway, a key pathway involved in cellular energy supply, were quantified in preserved whole tissue from each larval family using liquid chromatography tandem mass spectrometry (LC‐MS/MS) to identify potential biochemical markers associated with thermal sensitivity. Clear family × environment interactions were observed, whereby some larval families exhibited negative rate‐increases with warmer environments as opposed to others that exhibited enhanced respiration rates. Neither total metabolite content nor the abundance of single metabolite(s) were associated with family‐specific trends in respiration rate with temperature. Our findings highlight the use for identifying contrasting phenotypes among pedigreed families of Atlantic salmon and their potential in selective breeding programs for tolerance to dynamic environmental conditions.

Canadian salmonid aquaculture provides a sustainable protein source; however, there are concerns that Atlantic salmon (Salmo salar L.) mariculture reduces wild Pacific salmon survival through interspecific disease transfer. Tenacibaculosis, caused by species of Gram‐negative bacteria in the genus Tenacibaculum, has the potential to be transmitted interchangeably between farmed Atlantic salmon and wild Pacific salmon, though there is a lack of corroboration establishing transmission. To provide evidence for interspecific horizontal transmission of tenacibaculosis from Atlantic salmon to Pacific salmon, Atlantic salmon were bath‐exposed to an isolate of Tenacibaculum maritimum and cohabitated with naïve Atlantic or Chinook salmon (Oncorhynchus tshawytscha W.) for 25 days. Exposed and naïve cohabitant Atlantic salmon exhibited morbidity with multifocal superficial and ulcerative epidermal lesions with intralesional T. maritimum (culture, histology, and qPCR). At 108 CFU mL−1, exposed and naïve cohabitant Atlantic salmon had 43% and 60% mortality, respectively. Contrastingly, cohabitant Chinook salmon experienced no morbidity or mortality, despite successful culture of T. maritimum (108 CFU mL−1n = 5/6 fish; 106 CFU mL−1n = 0/6 fish) from skin swabs. These findings suggest that BC Chinook salmon do not develop clinical tenacibaculosis through interspecific horizontal transmission from farmed Atlantic salmon with mouthrot under the tested conditions and that the presence of T. maritimum alone is insufficient for disease. Further research needs to clarify the genetic differences between hosts and pathogens in different geographical locations, and investigate additional T. maritimum isolates, alternative Tenacibaculum species, environmental variables, and temporal scales that could lead to clinical tenacibaculosis in Chinook salmon.

A 90‐day nutritional trial was conducted to evaluate the effect of two dietary carbohydrate to lipid ratios and an attractant, star anise oil (Illicium verum), on marron (Cherax cainii Austin and Ryan, 2002) growth and organosomatic indices at 18 and 22°C under laboratory conditions. Three isonitrogenous diets were formulated, with two different carbohydrate to lipid (CHO:L) ratios, each with a crude protein level of 35%: D1 (CHO:L of 3.32), D2 (CHO:L of 3.22 + star anise oil), and D3 (CHO:L of 5.77 + star anise oil). Protein sources were also adjusted in D3 to allow for the higher carbohydrate content. Marron were held in cages to prevent cannibalism and to allow for individual feeding. The marron cultured at 22°C and fed D1 produced the highest specific growth rate (SGR), weight gain (WG), lowest molt intervals (MIns), and the lowest feed conversion ratios (FCRs). At 18°C, the highest molt frequency (MF) was in marron fed D1. The apparent feed consumption was highest at 22°C, and was unaffected by any diet. The total meat yield of marron was higher at 22°C when fed D3. The condition factor (CF) and organosomatic indices were unaffected by the diet, except the tail muscle moisture content (TM%) which was highest in marron fed D3 at 22°C. The supplementation of star anise oil did not increase the ingestion rate, and therefore, did not increase growth rates under laboratory conditions. Furthermore, a dietary carbohydrate to lipid ratio of 3.32 produced the highest growth rate of juvenile marron at 22°C, whereas there was no significant effect of diet on the growth rates at 18°C.

Nile tilapia (Oreochromis niloticus) supports both capture and aquaculture fisheries in Kenya, contributing 80% of the total annual aquaculture production. Poor management practices in fish hatcheries, resulting in inbreeding and a lack of genetic improvement and breeding strategies, have hampered the sustainable growth of farmed O. niloticus in Kenya. The native populations of O. niloticus suitable for use as the foundation stock for selective breeding are often threatened by hybridization and introgression, through uncontrolled transfer of genetic material across basins, especially with the introduction of cage aquaculture of O. niloticus in Lake Victoria. A study was initiated to assess the genetic diversity and population structure of O. niloticus from major hatcheries and natural stock from Lakes Victoria and Turkana. Eight microsatellite DNA markers designed for O. niloticus were used to genotype 89 natural and cultured individuals from 11 different sites in Kenya. Genetic diversity was moderate, with an overall mean of 5.46 alleles and 3.88 effective alleles per locus. Kamuthanga farm showed the highest allelic richness (7.63), followed by Turkana natural (6.75), while both Busia caged and Busia natural populations had the lowest (4.00). Analysis of molecular variance (AMOVA) results indicated that 95% of genetic variation occurs within the population, while only 2% is attributed to differentiation among populations, indicating strong within‐population structuring. STRUCTURE outputs were summarized using STRUCTURE HARVESTER, which identified K = 3 as the optimal number of genetic clusters, indicating the presence of three genetically distinct subpopulations among the sampled tilapia. Usenge caged and Turkana formed Cluster 1, Victory, and Kenya Marine and Fisheries Research Institute (KMFRI) farmed populations formed Cluster 2, while Homa Bay and Dunga natural populations comprised Cluster 3, showing close genetic similarity. These results indicate a well‐defined hierarchical structure at K = 3, representing the best fit for the dataset across all populations. High genetic diversity observed in farmed populations with a history of selective breeding, like KMFRI, demonstrates the need to operationalize such programs within the policy framework. The within‐population variability demonstrated in this study could be leveraged to design breeding programs based on marker‐assisted selection framework for increased aquaculture productivity.

The present study was performed to investigate the basic chemical composition and nutritional value of 10 terrestrial plant leaves (viz. Mangifera indica, Litchi chinensis, Artocarpus heterophyllus, Ziziphus mauritiana, Albizia lebbeck, Tamarindus indica, Cicer arietinum, Bauhinia acuminata, Delonix regia and Peltophorum pterocarpum) abundant in tropical and subtropical environments. The leaf meals were evaluated comprehensively, encompassing proximate composition (% dry matter), amino acids, fatty acids, antinutritional factors (ANFs), antioxidants and antibacterial potential using established methodologies. The crude protein (CP) content of the leaves ranged from 10.92% to 20.74% (w/w), with the highest content observed in A. lebbeck leaves. The crude lipid (CL) and crude fibre (CF) contents varied between 1.23%–5.38% and 13.73%–24.63%, respectively (w/w). The protein‐to‐energy ratio (P/E) ranged between 32.32 and 60.70 mg/kcal, with significantly higher (p < 0.05) P/E in A. lebbeck compared to the other leaves. Dominant fatty acids in the evaluated plant leaves included palmitic acid (C16:0), oleic acid (C18:1n9c) and linolenic acid (C18:3n3). Considerable amounts of essential amino acids (EAAs) and nonessential amino acids (NEAAs) were recorded in the plant leaves, with maximum quantities detected in A. lebbeck and A. heterophyllus, respectively. Notably, substantial amounts of mineral elements were also detected in the plant leaves. Z. mauritiana was identified as a rich source of iron (Fe), copper (Cu) and manganese (Mn), while the highest calcium (Ca), phosphorus (P) and magnesium (Mg) levels were recorded in A. heterophyllus. Furthermore, the aqueous extracts of the leaves exhibited antioxidant and antibacterial potentials, with the maximum activities for both observed in T. indica. Analyses of ANFs indicated the presence of trypsin inhibitor (TI) (1.62–3.69 mg/g), tannin (21.25–61.25 mg/g), phytic acid (1.74–5.42 mg/g), cellulose (14.53%–21.37%) and hemicellulose (5.48%–10.56%) in the leaves. The study conclusively proposes the utilization of leguminous plants, particularly A. lebbeck, B. acuminata and P. pterocarpum, as potential nonconventional ingredients after eliminating or deactivating the major ANFs. This information on nutrients and ANFs of the less explored terrestrial plant leaves can be used to optimize low‐cost carp diet formulation to ensure the economic profitability of fish farmers in the region.