Arnold Ebuka Irabor, Rodrigue Yossa, Nurul Ahmad Fatan
et al.
The aquaculture sector plays a key role in ensuring food and nutritional security as well as fostering economic growth in sub-Saharan Africa (SSA). However, as the sector continues to grow, its future faces economic, environmental, and sustainability challenges. At the core of these challenges are the substantial nutritional and health requirements of the farmed fishes that are cultured semi-intensively and intensively. Nutrient-balanced feed resources like fish meal and soybean are highly indispensable in most aquaculture production systems in SSA. However, these ingredients are limited, expensive, and are also in direct competition with farmed terrestrial animals and humans. Additionally, frequent disease outbreaks, especially due to the impact of climate change, pose viability challenges that are traditionally controlled using chemotherapeutics. But their indiscriminate usage has led to the occurrence of resistant microbes in the environment further adding to the challenges. Functional ingredients (FIs), derived from plants and microbial sources, are emerging as viable options to address both the nutritional and health issues of farmed fish. FIs contribute to fish health, growth performance, and resilience to disease and stress not only through their antioxidant, immunomodulatory, and antimicrobial properties but also by their nutritional benefits. The incorporation of these ingredients, into fish feeds can greatly reduce production costs, ecological footprint, and reliance on finite marine resources and synthetic drugs. However, FIs, with a few exceptions, have not been widely adopted in the aquafeed industry. This review aims to critically examine the reasons behind their limited adoption in the aquafeed industry, identifying key challenges and research gaps that hinder their widespread application. Additionally, it explores and evaluates the potential role of FIs in formulating cost-effective and functional aquafeeds with a low ecological footprint. A particular focus is given to their role in enhancing aquaculture productivity in the SSA region, highlighting opportunities for sustainable growth and the need for further research to optimize their efficacy and commercial viability.
Josh Pinskier, Sarah Baldwin, Stephen Rodan
et al.
Climate change, invasive species and human activities are currently damaging the world's coral reefs at unprecedented rates, threatening their vast biodiversity and fisheries, and reducing coastal protection. Solving this vast challenge requires scalable coral regeneration technologies that can breed climate-resilient species and accelerate the natural regrowth processes; actions that are impeded by the absence of safe and robust tools to handle the fragile coral. We investigate ReefFlex, a generative soft finger design methodology that explores a diverse space of soft fingers to produce a set of candidates capable of safely grasping fragile and geometrically heterogeneous coral in a cluttered environment. Our key insight is encoding heterogeneous grasping into a reduced set of motion primitives, creating a simplified, tractable multi-objective optimisation problem. To evaluate the method, we design a soft robot for reef rehabilitation, which grows and manipulates coral in onshore aquaculture facilities for future reef out-planting. We demonstrate ReefFlex increases both grasp success and grasp quality (disturbance resistance, positioning accuracy) and reduces in adverse events encountered during coral manipulation compared to reference designs. ReefFlex, offers a generalisable method to design soft end-effectors for complex handling and paves a pathway towards automation in previously unachievable domains like coral handling for restoration.
Purpose: The purpose of the work is to determine and analyze the main parameters, which characterize the impact of fisheries activities on the conditions for biological amelioration of the cooling pond of the Khmelnytskyi NPP.
Methodology. Ichthyological material was selected from commercial catches of gillnets with a mesh size of 36-120 mm in the summer-autumn period of 2021 and the autumn period of 2024. A total of 244 net-days were analyzed, of which 2268 individuals of different species were collected for mass measurements, and 434 individuals for full biological analysis. The collection and analysis of materials were carried out according to generally accepted methods. To assess the theoretical survival of silver and bighead carps, the annual natural mortality rate was used, which was determined based on the natural mortality rate calculated using the parameters of the Bertalanffy equation. The abundance of silver and bighead carp generations for a given year was determined based on the volume of stocking, average natural mortality rates, and commercial catch parameters. The volume of stocking and catch was taken from official reporting data. Calculations were performed in MS Excel 2016.
Findings. The majority of the commercial stock of the ichthyofauna of the studied pond in recent years were silver and bighead carps (on average 32.7%), Prussian carp (18.7%), roach (15.1%) and common carp (10.8%), the composition of dominant species was characterized by stability, with the exception of an increase in the share of Prussian carp. The actual stocking rates of the pond generally corresponded to the planned ones, however, the commercial catches amounted to only 12% of the planned ones.
The average total mortality for middle age groups, according to the analysis of the catch curve, was φZ=0.42, which allows assessing their estimated annual catch at the level of φF=0.03…0.07. In contrast, for older age groups, the total annual mortality rate was φZ=0.47, while the average estimated annual fishing mortality was φF=0.26…0.27. Meanwhile, calculations of annual natural mortality for older age groups based on the analysis of the catch structure and catch statistics data gave the value φF=0.01…0.05.
To localize the negative impact of secondary (due to increased natural mortality) pollution of the pond at an acceptable level, it is necessary to introduce moderate harvest of ichthyomas of middle age groups of biological control agents with an annual fishing mortality coefficient at the level of φF =0.05-0.10, and increased catch of age groups from age-7 and older with φF=0.30…0.40. To ensure maximum effect of biological control, the optimal gears for catching silver and bighead carps are gill nets with a mesh size of a=90-100 mm.
Originality. General trends in the dynamics of integral characteristics of the commercial stock of silver and bighead carps were determined in the context of the scientific fundamentals of managing the biomass of biological control agents. The knowledge on the methodological principles of ensuring the effectiveness of biological amelioration of technical water bodies has been deepened.
Practical value. The results obtained were used to adjust the procedure for fishery exploitation of the Khmelnitsky NPP pond in order to implement biological amelioration through the directed development of ichthyofauna.
Similar to other macroalgae, Saccharina japonica has CO2-concentrating mechanism (CCM) that allows high photosynthesis efficiency and elevates biomass. Phosphoenolpyruvate carboxykinase (PEPCK) in cytoplasm is an essential component of CCM. However, no reports on cytosolic PEPCK of S. japonica are available. In this study, the full-length cDNA sequence of a PEPCK gene (SjPCK1) predicted to be localized in cytoplasm, was screened from the full-length transcriptome of S. japonica gametophytes and identified by RT-PCR. The complete cDNA sequence of SjPCK1 was 2174 bp in length, which encompassed an open reading frame (ORF) of 1734 bp, a 5′- untranslated region (UTR) of 216 bp and a 3′-UTR of 224 bp. In parallel, the genomic DNA of SjPCK1 was 21 294 bp in length, characterized by the presence of 11 introns and 12 exons. It encoded a protein of 577 amino acids with a molecular weight of 63 kD and an isoelectric point of 8.47. Amino acid sequence alignment showed that the functional sites of PEPCK were highly conserved in the selected species. Phylogenetic analysis and sequence characterization showed that SjPCK1 was an ATP-dependent PEPCK. SjPCK1 gene was expressed by using Escherichia coli prokaryotic expression system, and the SjPCK1 protein with His 6 tag (rSjPCK1) was 81.93 kD in molecular weight. Enzyme activity assay results showed that the specific activity of carboxylase and decarboxylase of rSjPCK1 was 1.91 ± 0.29 U/mg prog and 11.3 ± 1.97 U/mg prog, respectively. These findings provide valuable molecular and biochemical insights for a further analysis of the role of cytosolic PEPCK in the storage of inorganic carbon in S. japonica.
We investigate the temperature evolution in the three-dimensional skin tissue exposed to a millimeter-wave electromagnetic beam that is not necessarily perpendicular to the skin surface. This study examines the effect of the beam's incident angle. The incident angle influences the thermal heating in two aspects: (i) the beam spot projected onto the skin is elongated compared to the intrinsic beam spot in a perpendicular cross section, resulting in a lower power per skin area; and (ii) within the tissue, the beam propagates at the refracted angle relative to the depth direction. At millimeter-wavelength frequencies, the characteristic penetration depth is sub-millimeter, whereas the lateral extent of the beam spans at least several centimeters in applications. We explore the small ratio of the penetration depth to the lateral length scale in a non-dimensional formulation and derive a leading-term asymptotic solution for the temperature distribution. This analysis does not rely on a small incident angle and is therefore applicable to arbitrary angles of incidence. Based on the asymptotic solution, we establish scaling laws for the three-dimensional skin temperature, the skin surface temperature, and the skin volume in which thermal nociceptors are activated.
Eliana Ruiz Martínez, Declan C. Schroeder, Gunnar Thuestad
et al.
Brown algae (Phaeophyceae) dominate intertidal and shallow subtidal areas globally, where larger species form extensive underwater forests. These structurally complex and highly productive habitats enhance local biodiversity and support food webs in coastal areas through secondary production, thereby shaping local oceanography and ecology. Macroalgal aquaculture is an important and growing sector, where approximately 40% of all cultivated algae belong to Phaeophyceae. However, both cultured and natural brown algae have been under increasing pressure due to climate-driven factors, such as ocean warming, eutrophication, and herbivore outbreaks. We conducted a comprehensive literature review on abiotic (temperature, light intensity, and UV radiation, nutrients, water motion, salinity, and substrata and sediment) and biotic (bacteria, viruses, fungi, eukaryotic endophytes and endoparasites, epiphytes, and grazers) stressors and illnesses in marine brown macroalgae, as well as brown algae defense mechanisms, and discuss how these parameters may affect the production of a sustainable crop for the aquaculture industry under future climate change scenarios.
Awaad A. El-Sayed, Mohamed A. Amer, Abdallah M. Abdalkhalek
et al.
The results of this study showed that out of 287 individuals (135 males and 152 females) of the spider crab Menaethius monoceros collected from the Red Sea and the Gulfs of Suez and Aqaba, 15 individuals (6 males and 9 females) were infected with Parasacculina pilosella (Van Kampen & Boschma, 1925) (Polyascidae: Rhizocephala: Cirripedia: Crustacea). A total of 20 externae were recorded, including 11 singles, three doubles, and only one triple on the infected crab abdomens. The overall infection rate was 5.23% for the combined sexes at all sites, declined to 4.44% in males, but increased to 5.92% in females, reaching a higher rate of 16.07% in the populations of Marsa Alam and Shalateen sectors during summer. The examined externae have variable colors, sizes, and shapes based on their sexual maturity, which has been classified into four stages: immature or virgin, early mature, maturing, and late (spent externae). The largest number of externae was eight extruded on the 3rd abdominal segment, while it decreased to six, two, and one on the 4th, 2nd and 5th segments, respectively. The size of externae varied from 1.3 × 1.0 × 1.0 to 6.3 × 4.5 × 2.5 mm (Breadth × Height × Thickness). These results showed changes in the external secondary sexual characters of the infected males, represented by the remarkable broadness of the abdomen fringed with marginal setae and invagination of the sternum, but were limited in infected females.
This study evaluated the growth performance, immune response, hepatopancreatic health, and disease resistance in Litopenaeus vannamei fed diets supplemented with fermented pomegranate peel polyphenols (FPPP) for 45 days. Five diets were formulated to contain various levels of FPPP: FP0 (no FPPP), FPPP inclusion at 0.015% (FP1), 0.030% (FP2), 0.060% (FP3), and 0.120% (FP4). The results indicated there were no significant variations in weight gain rate (WGR), specific growth rate (SGR), and feed conversion rate (FCR) of shrimp in all treatment groups (p>0.05), but the survival (SR) of shrimp was significantly higher in all groups with the addition of FPPP (p<0.05). Compared with FP0 group, the contents of total protein (TP) and globulin (GLB) in serum biochemical indexes of FP3 and FP4 groups were significantly increased, and the content of blood urea nitrogen (BUN) was significantly decreased (p<0.05). Compared with FP0 group, the activities of superoxide dismutase (SOD), catalase (CAT), alkaline phosphatase (AKP), acid phosphatase (ACP), and lysozyme (LZM) in the hepatopancreas and serum of FP3 and FP4 groups were significantly increased (p<0.05). Similarly, the activities of glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and phenoloxidase (PO) in the hepatopancreas and serum of FP2 group were significantly higher than those of FP0 group (p<0.05). In addition, the content of malondialdehyde (MDA) in the hepatopancreas and serum of shrimp in FPPP-added groups was decreased (p<0.05). Compared with FP0 group, the expression levels of SOD, CAT, glutathione S-transferase (GST), LZM, prophenoloxidase (ProPO), penaeidin-3 (Pen3), Crustin, immune deficiency (Imd), Toll, and Relish genes were significantly upregulated in the hepatopancreas of shrimp in FP3 and FP4 groups (p<0.05). Additionally, increasing the addition level of FPPP resulted in a more compact hepatosomal arrangement of the shrimp’s hepatopancreas, a more visible star-shaped lumen structure, and a significantly higher number of B cells. Finally, the cumulative SR of shrimp in FPPP groups was significantly higher than that in FP0 group after 7 days of infection with Vibrio alginolyticus (p<0.05). In summary, dietary supplementation of FPPP can improve SR, immunity, and hepatopancreatic health and resistance to Vibrio alginolyticus of L. vannamei.
Recently contact angle hysteresis in two-dimensional droplets lying on a solid surface has been studied extensively in terms of static friction due to pinning forces at contact points. Here we propose a method to determine the coefficient of static friction using two-dimensional horizontal capillary bridges. This method requires only the measurement of capillary force and separation of plates, dispensing with the need for direct measurement of critical contact angles which is notoriously difficult. Based on this determination of friction coefficient, it is possible to determine the Young's angle from its relation to critical contact angles (advancing or receding). The Young's angle determined with our method is different either from the value estimated by Adam and Jessop a hundred years ago or the value argued by Drelich recently, though it is much closer to Adam and Jessop's numerically. The relation between energy and capillary force shows a capillary bridge behaves like a spring. Solving the Young-Laplace's equation, we can also locate the precise positions of neck or bulge and identify the exact moment when a pinch-off occurs.
In this work, we extend the model of contact angles that we have previously developed for sessile drops on a wetted surface to the case of a meniscus in a capillary. The underlying physics of our model describe the intermolecular forces between the fluid and the surface of the capillary that result in the formation of a thin, non-removable fluid layer that coats the capillary wall. We describe the shape of the meniscus using a Young-Laplace equation and an incompressible, two-phase, CFD calculation, both modified to take into account intermolecular forces using the disjoining pressure model. We find that our numerical solutions of the Young-Laplace equation and equilibrium meniscus shapes obtained by CFD agree well with each other. Furthermore, for capillaries that are sufficiently larger than the thickness of the non-removable film, our numerical solutions agree well with the effective contact angle model that we previously developed for sessile drops. Finally, we observe that it is possible to tune the disjoining pressure model parameters so that the intermolecular forces between the liquid and solid molecules becomes so strong compared to the surface tension that our formula for effective contact angle gives an imaginary solution. We analyze this situation using CFD and find that it corresponds to dewetting, where the bulk liquid detaches from the walls of the capillary leaving behind the non-removable thin liquid film.
For an angle $α\in (0,π)$, we consider plane graphs and multigraphs in which the edges are either (i) one-bend polylines with an angle $α$ between the two edge segments, or (ii) circular arcs of central angle $2(π-α)$. We derive upper and lower bounds on the maximum density of such graphs in terms of $α$. As an application, we improve upon bounds for the number of edges in $αAC_1^=$ graphs (i.e., graphs that can be drawn in the plane with one-bend edges such that any two crossing edges meet at angle $α$). This is the first improvement on the size of $αAC_1^=$ graphs in over a decade.
We test the viability of training machine learning algorithms with synthetic H alpha line profiles to determine the inclination angles of Be stars (the angle between the central B star's rotation axis and the observer's line of sight) from a single observed medium-resolution, moderate S/N, spectrum. The performance of three different machine learning algorithms were compared: neural networks tasked with regression, neural networks tasked with classification, and support vector regression. Of these three algorithms, neural networks tasked with regression consistently outperformed the other methods with a RMSE error of 7.6 degrees on an observational sample of 92 galactic Be stars with inclination angles known from direct H alpha profile fitting, from the spectroscopic signature of gravitational darkening, and, in a few cases, from interferometric observations that resolved the disk. The trained neural networks enable a quick and useful determination of the inclination angles of observed Be stars which can be used to search for correlated spin axes in young open clusters or to extract an equatorial rotation velocity from a measurement of v sin(i).
Hany Handajani, Dony Prasetyo, Sri Dwi Hastuti
et al.
Purpose the research to know influence giving leaf durian infused
to anesthesia process gurami fish with weight 100-150 gr use
predetermined dosage by upper threshold test and lower
threshold test. Then, use formula EC-100 (Effektivity
Consentrastion) to know fainting time fish and conscious time
fish. On threshold test use among others concentrate 1000ppm,
2500ppm, 5000ppm and 7500ppm. That at concentration
7500ppm is upper threshold because gurami fish die by soaking
leaf Durian infused for 24 hours while at concentration 5000pm
is lower threshold because gurami fish not die by soaking leaf
Durian infused for 48 hours. Next to search concentration row
with use formula EC-100 and than available concentrate
5400ppm, 5900ppm, 6400ppm, 6900ppm and 7400ppm. The
concentration be used to research treatment, P1:5400ppm,
P2:5900ppm, P3:6400ppm, P4:6900ppm and P5:7400ppm. The
Method of this research is a complete random design (RAL) use
five treatments and three replications. The main parameter
observed lamely fainting time fish and conscious time fish. The
result fainting time fish (minute) on P1: 200, 67 P2: 198,33 P3:
196 P4: 193 and P5: 186,67 while results conscious time fish
(minute) on P1: 22 P2: 22,67 P3: 23,33 P4: 28,33 and P5: 30,33.
Next statistic test use method ANOVA and BNT test with level 5%
indicate significantly different, and 1 % indicate very differently
real. The obtainable conclusion that research use leaf durian
infusum to anesthesia process gurami fish very differently real to
fainting time and conscious time. The best treatment on P5
(7400ppm) because gurami fish fast to fainting time and long a
for conscious time.
Keywords: Anesthesia; Durian Leaf; Gouramy; Infused; Saponin
The study was conducted with the aim of determining the influence of brief immersions in aqueous solutions of sodium chloride (NaCl) and/or copper sulphate (CuSO4) on the physiological state (hematological and blood plasma biochemical indicators) of pikeperch selects (body weight 509.89 ± 99.56 g; body length 33.9 ± 2.0 cm). Immersion was conducted in a water temperature similar to that of spawning (15.1°C). The fish were divided into three experimental groups and one control group: NaCl group (NaCl concentration – 5 g l−1), CuSO4 group (CuSO4 concentration – 1.5 mg l−1), and NaCl+CuSO4 group (NaCl concentration – 5 g l−1; CuSO4 concentration – 1.5 mg l−1). Blood was drawn immediately after immersion (0 h), 24, and 48 h following the conclusion of immersion. Immediately after immersion, elevated values were noted in white and red blood cell counts, hematocrit, and hemoglobin, while mean corpuscular hemoglobin concentration values were elevated only in the NaCl group 24 and 48 h following the conclusion of immersion. Changes in blood plasma biochemical indicators were noted only immediately after the conclusion of immersion with elevated values of glucose (NaCl, CuSO4, and NaCl+CuSO4 groups), lactate (NaCl and CuSO4 groups), and ammonia, sodium, and chlorine ions (CuSO4 group). Greater aspartate aminotransferase activity was noted in the fish from the CuSO4 group immediately after immersion, while the least significant changes following immersion were noted in specimens from the NaCl+CuSO4 group.
Abstract Despite the profitability of the wild Atlantic Sea Scallop, Placopecten magellanicus, fishery, the U.S. still imports more than 26,000 tonnes of various scallop products annually. Atlantic Sea Scallop (hereafter referred to as scallop) aquaculture is one method of mitigating this imbalance. We examined scallop growth at three sites across the mouth of Penobscot Bay, Maine to determine the coupled effects of lantern net stocking density and temperature on growth and mortality. Scallops were held in high and low (20 and 10 individuals tier−1, respectively) density treatments, and shell height measurements were recorded monthly for one year. We divided the growth rate analysis into three periods: winter - spring, summer, and fall. During summer across all sites, growth rates were 75 % higher in low-density nets than in high-density nets. We observed significant nonlinear relationships between shell height growth rate, temperature, and stocking density. Optimal growth occurred within a window of 10–15 °C. Above this threshold, there was a distinct negative relationship between temperature and growth. Our results highlight the importance of maintaining low densities within nets, particularly during periods of high temperature and growth. However, handling in summer and early fall may lead to mortality. Therefore, we recommend that growers stock nets at low densities in the spring, ensuring that they will not require thinning during peak temperatures. Similarly, finding sites that maximize time within a thermal envelope of 10–15 °C will be critical, which in the case of the Gulf of Maine will most likely warrant leasing sites at the mouths of estuaries and bays. These locations offer a combination of sufficient depth and space for sparsely stocked nets, adequate food levels, and optimal salinity and temperature.
Sea cucumber aquaculture is increasing in extent and importance throughout the Indo-Pacific region, supplying a luxury seafood market in Asia. In this context, the grow-out of hatchery-bred juveniles in community-farmed pens is proving to be a viable model, providing increased income security and alternative livelihood options to resource-limited communities. Here, we report a study of the impacts of such sea cucumber farming on the growth of seagrass (a favourable habitat for the animals) at a village-scale aquaculture site in southwest Madagascar. Using experiments, we found that the presence of the hatchery-bred sea cucumber Holothuria scabra (sandfish), at stocking densities of 300 g m-2 (similar to the density used in the farmed pens, but relatively high for natural populations), resulted in a large (~30%), statistically significant increase in the leaf extension rate of the locally dominant seagrass species Thalassia hemprichii. However, the other dominant seagrass species, Cymodocea serrulata, did not significantly change its leaf extension rate in the presence of H. scabra. Since seagrass is a globally important coastal habitat, supporting high biodiversity, carbon sequestration, shoreline stability and nursery grounds for commercial and small-scale fisheries, the positive effect of H. scabra farming on the growth rate of at least one dominant seagrass species implies potential important ecological co-benefits. These co-benefits of H. scabra farming are likely to be relevant across the tropical Indo-Pacific coastlines, where this species is cultured.
Chub mackerel Scomber japonicus and blue mackerel S. australasicus have become important aquaculture target species in Japan. For an efficient and stable aquaculture production of mackerels, it is desirable to work with a female-biased broodstock and thus to be able to manage precisely their sex ratio. As these two mackerel species do not have any external sexual dimorphism, direct biopsy of the gonads or measurement of sex hormone plasma levels is used in research to determine their phenotypic sex. However, these methods are associated with handling stress that results in gonadal atresia. Besides, it is difficult to identify sex using these methods in immature individuals. Therefore, genetic sexing would be desirable in these species to overcome these problems. In this study, we developed molecular sex identification tools for both chub and blue mackerels using sex-specific single-nucleotide variations (SNVs) identified by pool-sequencing (pool-seq) analyses. Genomic DNA was isolated from 30 males and females, in each species, and sequenced as pooled samples. Results of these pool-seq analyses identified a clear XX/XY male heterogametic sex-determination system in blue mackerel and a ZZ/ZW female heterogametic system in chub mackerel. Using this pool-seq information, we designed primer sets for genetic sex identification in both species. Results demonstrated that these primer sets are robust and accurate in assessing the genotypic sex of both blue and chub mackerels (accuracy > 99.5% in the chub, and > 94.5% in the blue mackerel) in various geographical samples of different ages. This method can now be applied for the efficient management of sex ratios in both mackerel aquaculture populations and wild-caught animals for fisheries management.