Total Length Research Articles

Morphometric Characterization and Fillet Yield of Two Commercial Fish Species from Panyam Fish Farm Plateau State

A total of 50 individual samples of Parachanna obscura and Clarias gariepinus were collected fresh from Panyam fish farm with the aid of crush ice for preservation until assessment was carried out to determine the fillet yield of Parachanna obscura in comparism with Clarias gariepinus. The whole fresh fish samples were taken to the department of Fisheries and Aquaculture laboratory of the Federal University, of Agriculture, Makurdi for assessment. Their Total and Standard Lengths were recorded (in cm) using a Measuring Rule, while Total Body Weights were recorded (in grams) using an electronic weighing balance. Data were collected on: the Total Weight (g), Total Length (cm), Standard Length (cm), Visceral Weight (g), Head Length (cm), Weight of Bones (g), Weight of Fins (g) and Weight of Fillet (g) in comparism between the two fish species. Descriptive statistics for morphometric data were determined using Minitab 18® (Minitab 2017). Regression and correlation of variables was carried out in R (R Core Team 2020). Results of the mean measured parameters of Parachana obscura and Clarias gariepinus from Panyam Fish Farm Jos, showed that Total Length (42.66 ± 0.58cm), Standard Length (38.56 ± 0.29cm), Fin Weight (15.51 ± 0.37g), Visceral Weight (11.04 ± 0.17g), Head Weight (1.49 ± 4.01g), Bone weight (39.84 ± 0.80g) and Weight of fillet (89.02 ± 2.38g) of Parachana obscura were higher than the mean measured parameters of Clarias gariepinus. There was a significant difference (p= .05) among the measured parameters between P. obscura and C. gariepinus. The higher fillet percentage per body weight of P. obscura in comparism to C. gariepinus is a pointer to a relatively higher economic value for commercial purposes of this species. This assessment also provides information for further studies on this species to be built on, as there is obvious need for Nigeria’s aquaculture system to diversify from the prevalent catfish culture.

BS SO11 - Impact of various biliopancreatic limb lengths on EBWL, Nutritional deficiencies and resolution of ORMs -MGB/OAGB

Abstract Background OAGB was first described by Robert Rutledge. There have been a few modifications of MGS since its first introduction. There have been modifications in the limb length, pouch side, type, and location of anastomosis. Concerns have been raised about nutritional deficiencies by various authors about the longer limb length. Few other authors have published promising results from their studies regarding good outcomes on longer limb length. Method We follow BMI based guidelines at our center to decide on OAGB limb length.BMI < 50- BP limb length – 150 cmBMI >50 BP limb length- 200 cmBMI > 60 BP limb length- 250 cm. We analysed our results from BP limb lengths >/=200 cm in terms of EBWL, ORM resolutions, Nutritional deficiencies and compared it to similar outcomes in BP limb lengths of 150 cm Results Our data is currently under review. Initial assessment suggests promising results of longer limb lengths with no major complications highlighted. All the longer limb length patients are under 3 monthly follow up with 2 years follow up data now being analysed. Literature review suggests inadequate weight loss with shorter limb lengths. The longer limb lengths are associated with nutritional deficiencies. We are excited to take this opportunity to discuss our results Conclusion Limb length should be tailored as per patient factors and available support. One standard limb length doesn't apply to all the patients.

Methods to characterize microplastics: case study on freshwater fishes from a tropical lagoon in Colombia.

Aquatic ecosystems face multiple anthropogenic pressures, and recently plastic pollution is one of the main problems. The Luruaco lagoon receives discharges from streams with high levels of microplastics (MPs) from urban areas that impact the resident ichthyofauna. We studied the prevalence, abundance and physical and chemical characteristics of MPs in fishes in the Luruaco Lagoon, Colombia. Four samplings were carried out where fish were captured with trawl nets. Each individual was assessed for total weight, total and standard length, and then a uroventral cut was made to extract stomach and intestine (GIT). Each structure was weighed, measured, and deposited in glass jars with filtered KOH solution. The abundance of MPs and frequency of occurrence were assessed. A principal component analysis (PCA) was used to describe the variation of the species dataset (%FO, proportion of MPs and their diet). Seven species were recorded and 271 individuals examined: Microplastics were identified in all species, and 1157 particles were found in their GIT, with a prevalence of 87.5% of MPs. Mugil liza and Andinoacara latifrons had a high proportion of MPs. The highest %FO was found in cichlid species. Four typologies and 13 colors of MPs were analyzed; fibers and color blue were predominant. A direct relationship was observed between the type of diet and the proportion and %FO of MPs.

Using micro-CT to explore bone density variations in the skulls of the vulnerable Opsariichthys uncirostris uncirostris (Three-lips fish) during reproductive migration to a Lake Biwa tributary.

Not much is known about the changes in bone density due to fish reproductive migration. We used micro-CT and inferential statistics to determine whether the relative bone density in the skulls of adult Three-lips fish, that seasonally upstream migrated to a Lake Biwa tributary, changed across their known reproductive season. The relative bone density significantly decreased as standard length and condition factor (K) increased in both sexes. This negative relationship is likely due to age and hormonal effects in the fish. Results from the bone density analysis also revealed that male Three-lips fish had potentially lower relative bone density (although not significantly different) than females during peak reproductive migration, i.e., July to August. On average, male Three-lips fish are larger in length and weight than females, and in many species, females prefer larger males to smaller males, viewing their size as an indicator of genetic fitness and their ability to provide protection. Resources in the skulls of Three-lips males may be distributed in such a way that increases reproductive success, i.e., size at the expense of quality. In addition, individuals with slightly less dense bones, particularly males, appeared later than those with denser bones during the peak of the reproductive season. The high energy demands involved with aggression in males, often requires resource mobilization from various tissue compartments and could explain the slightly lower density in the latter half of the peak migration. Furthermore, Three-lips individuals that migrated earlier and later during the reproductive season may have more energy reserves than those that had been in the river for some time, hence the variable bone density between individuals. This study serves as a foundation for future studies on the effects of migration, changes in physiology and age on bone density analysis of Three-lips fish and other species in various ecosystems.

Ray-Resorption Syndrome in European Seabass, Dicentrarchus labrax (Linnaeus, 1758).

Fin abnormalities are common in reared fish. They mainly consist of partial to complete lack of rays and severe abnormalities of fin-supporting skeletal elements, which develop during the larval stage, up to the completion of fin skeleton ontogeny. This study reports a new abnormal condition, ray-resorption syndrome (RSS), which developed after the completion of fin ontogeny in initially normal European seabass larvae, leading to extensive loss of fin rays. At 49 days post-fertilisation (dpf) (15 mm standard length, SL) all fish presented normal fins. However, nineteen days later (21 mm SL), significant fin damage, characterised by ray loss or fractures, was observed in all studied populations. The dorsal fin was most affected (55%-84%), followed by the pelvic (27%-53%) and anal fins (7%-17%). Microscopically, multiple non-mineralised areas resembling resorption lacunae were evident along all fin lepidotrichia. By 98 dpf (40 mm SL), the fin-ray loss had advanced, reaching its higher frequency in the dorsal (74%-83%) and caudal fins (71%-94%). Gene expression analysis revealed a significant upregulation of bglap (osteoblast maturation marker), acp5a (osteoclast maturation marker) and mmp13a (extracellular-matrix remodelling marker) in RSS specimens. The results are discussed in respect of the possible causative factors of RSS.

Occurrence of juvenile porbeagle sharks (Lamna nasus) in the northern coast of Spain.

Opportunistic records can provide valuable information on certain species, including the critically endangered porbeagle shark (Lamna nasus). This note documents the occurrence of three juveniles, with approximate 120-, 88-, and 85-cm fork lengths respectively, observed along the coast of Asturias, Spain, in 2024. Given the three distinct scenarios in which these records respectively occurred (incidental capture, washed ashore and stranding), they emphasize the role of citizen science in identifying potential threats to this species, particularly in early stages of life, in a region that may be important and previously overlooked.

Numerical Simulation and Experimental Validation of the Acoustical Target Strength of Bluefin Tuna Swimbladders Derived from 3D Computed Tomographic Images

The swimbladder, when present, is the main contributor to the acoustical target strength (TS) of fish. Numerical modeling of target strength must include swimbladder dimensions, orientation, and shape for the proper estimation of target strength and its directivity. Several Atlantic Bluefin tuna (Thunnus thynnus, ABFT) specimens between 90 and 100 cm of fork length were studied by performing computed tomographic (CT) post-mortems in both fresh and frozen states. ABFT swimbladder 3D models were derived for the first time to be compared with experimental TS measurements through numerical simulation methods, using the Method of Fundamental Solutions (MFS). The numerical estimation (−23.3 dB) agreed with the experimental measurement of TS (−22.1 dB) performed in a tank with tuna with a mean fork length of 100 cm, showing the importance of considering realistic swimbladder shapes and swimming behavior in the numerical simulation of TS.

A new species of Hoplostethus from Sumatra, eastern Indian Ocean, with comments on its most similar congeners (Trachichthyiformes: Trachichthyidae).

A new species of the roughy fish genus Hoplostethus, subgenus Leiogaster, is described based on three specimens collected from Sumatra, Indonesia. This species can be distinguished from its congeners by the following characteristics: gular region covered with ctenoid scales; pelvic-fin spine smooth on its anterior edge; head depth subequal or smaller than its length (37.2%-38.6% standard length [SL], or 94.7%-99.2% head length [HL]); pectoral-fin length 35.6%-37.8% SL, reaching beyond a vertical through anal-fin origin; abdominal scutes well developed, 12-16; pectoral-fin rays uniformly black, 17-19; gill rakers on the first arch 6-7 + 1 + 13-14 = 21; pre-dorsal scales 24-27; and pyloric caeca 32. A detailed description is provided along with comparisons with its congeners. Additionally, diagnostic characters of the congeners and literature records of Hoplostethus rubellopterus and Hoplostethus melanopus are discussed.

Early intravenous branched-chain amino acid-enriched nutrition supplementation in older patients undergoing gastric surgery: a randomized clinical trial

BackgroundThe initiation time and formula for supplemental parenteral nutrition after surgery require optimization, especially in older patients undergoing major gastrointestinal surgery. This study aimed to assess the effect of early supplementation with a branched-chain amino acid (BCAA)-enriched formula (BAF) on short-term postoperative outcomes in older patients undergoing gastric surgery.MethodsThis single-center, prospective, double-blinded, randomized clinical trial was conducted from March 10, 2020, to September 15, 2022. Patients aged 65–80 years with gastric cancer scheduled for curative resection were assessed for eligibility and randomly allocated to a high-proportion BCAA (HBCAA) (early supplementation with the BAF) or control (routine nutrition) group. The primary outcome was the standardized length of hospital stay (LOS).ResultsA total of 150 patients were randomized. Thirteen patients were excluded due to the resection of other organs, presence of metastasis, or withdrawal of consent. Finally, we included 70 and 67 patients in the HBCAA and control groups, respectively (mean age: 70.5 ± 4.2 years; 96 men [70.1%]). The standardized LOS was significantly shorter in the treatment group than in the control group (median [interquartile range]: 8.0 [7.8, 8.0] vs. 8.5 [8.0, 9.0] days; mean difference, 0.38; 95% confidence interval [CI], 0.02–0.74 days; P < .001). Patients in the HBCAA group showed better gastrointestinal function with faster defecation (4.0 [3.6, 5.0] vs. 5.0 [4.0, 5.5] days; mean difference, 0.6 days; 95% CI, 0.26–0.94 days; P < .001) and semi-liquid diet initiation (8.0 [7.5, 8.0] vs. 8.0 [8.0, 8.8] days; mean difference, 0.36 days; 95% CI, 0.03–0.7 days; P < .001) and had lesser weight loss at postoperative day 5 than those in the control group did (3.5 [2.7, 6.5] vs. 4.9 [3.3, 7.6]%; mean difference, 1.23%; 95% CI, 0.27–2.19%; P = .011).ConclusionsIn this randomized clinical trial, compared with routine nutrition, early supplementation with a BAF was associated with a shorter standardized LOS in older patients undergoing gastric surgery, suggesting that it may be a favorable strategy for patients with a poor tolerance to external nutrition who are undergoing major surgery.Trial registrationClinicalTrials.gov; Identifier: ChiCTR2000029635.

Efecto del uso de harina de plátano dominico (Musa simmonds) y tapioca (Manihot esculenta) como fuente de carbono en el cultivo de Barbo tigre (Puntius tetrazona) en sistema biofloc

The objective of this study was to evaluate the effect of three carbon sources: molasses (Control), tapioca flour and banana peel, for the development of a biofloc system in the culture of the ornamental fish Puntius tetrazona. To ensure floc formation, a C/N ratio=20:1 was maintained for each of the carbon sources, considering three replicates per treatment. According to the results, the environmental parameters showed fluctuations, especially in the first three weeks of culture, within the optimal ranges for the species. Fish growth expressed as biomass gain did not show significant differences (P &gt; 0.05) among treatments, but the standard length did (P &lt; 0.05). The highest absolute and specific growth rates were obtained in plantain peel and tapioca, regarding the feed conversion factor, molasses had the highest value (0.91 g), followed by tapioca with 0.27 g, and banana peel with 0.25 g. Survival was 100% in the banana peel group, followed by tapioca, and molasses. The Phyla of microfauna recorded in the experimental groups were, Ciliphora, Rotifera, Annelida, Nematoda, Plathelmintes, Gastrotricha, and Amoebozoa with variations among treatments throughout the experiment. The results of the present study demonstrate the potential of using Dominican plantain hull meal as a carbon source for the development of ornamental fish cultures in biofloc, being an option that, due to its low cost, will increase the profitability of the cultures. Key words: Biofloc, tiger barbel, molasses, banana peel, tapioca.

Characterization of micro-wire electrical discharge machining surface texture by empirical mode decomposition

Surface roughness is a critical factor for the operational efficacy and lifespan of the manufactured components, often serving as a key metric for evaluating manufacturing processes and determining acceptance of a component. Traditional surface roughness measurements are highly sensitive to the fixed standard cut-off length, influencing the scale at which surface texture features are analyzed. Thus, developing techniques with more reliable filtering of surface features is essential for accurate surface metrology. This research proposes a novel method that combines Empirical Mode Decomposition (EMD) and Fast Fourier Transform (FFT) for surface roughness characterization. We applied our method to Nitinol shape memory alloy (equal atomic proportions of nickel and titanium) surfaces processed using micro-Wire Electrical Discharge Machining (μ-WEDM). Our results demonstrate that the EMD-FFT method significantly outperforms traditional filtering, especially for surfaces without distinct patterns like μ-WEDM. This improvement is particularly valuable for materials like Nitinol, which is widely used in critical applications where precise surface roughness control is essential. By accurately assessing the effects of μ-WEDM parameters on surface roughness, the proposed method reveals that for a constant pulse on time and a constant discharge current, the variation of pulse off time is more important than servo voltage. Thus, this method can contribute to optimizing manufacturing processes and producing higher-quality components with improved performance and durability.

Dorsal fin height is not an effective tool to distinguish hatchery and wild steelhead in the field

AbstractObjectiveTo maximize harvest of hatchery steelhead Oncorhynchus mykiss and Pacific salmon Oncorhynchus spp. while reducing impacts to wild conspecifics, fishery managers rely on the ability of anglers to distinguish between the two. Fin erosion, including dorsal fin erosion, is a common result of hatchery rearing of juvenile salmonids. Since the 1980s, managers in the Pacific Northwest have utilized adult steelhead dorsal fin height as a regulatory control rule, requiring anglers to release steelhead with dorsal fins over a height threshold. This approach assumes that all or most hatchery fish have shorter dorsal fins than their wild counterparts. This study was designed to test this assumption.MethodsWe compared steelhead origin (hatchery or wild) determined using scale analysis and adipose fin clipping (hatchery n = 127, wild n = 71) with origin estimated using dorsal fin height.ResultOverall, a static dorsal fin height threshold (2.25 in, 5.72 cm) correctly identified 90% of hatchery‐origin steelhead but misidentified nearly half (44%) of wild fish as hatchery. Dorsal fin height of known hatchery fish correlated with fish length, indicating a weakness of using a static dorsal height threshold as a management tool. The accuracy of distinguishing wild fish improved, but only marginally (56–76%), using a classification model where dorsal fin height of known origin fish from this study was a continuous predictor of origin. In comparison, adipose fin status correctly identified 97% of unmarked fish as wild.ConclusionThe low accuracy of the classification model and static dorsal fin height thresholds at distinguishing hatchery and wild steelhead due to a strong correlation between dorsal fin height and fork length and the high fork length variability of hatchery origin fish. Given the low cost and accuracy of adipose fin clipping and the potentially high conservation risk associated with misidentification, we recommend discontinuing the use of dorsal fin height as a harvest control rule for steelhead.

Deep Dive Into Noninvasive Biometrics: A Pilot Journey Using Stereo-Video in a Public Aquarium.

Accurate collection of biometric data is important for understanding the biology and conservation of marine organisms, including elasmobranch and teleost fish, both in nature and controlled environments where monitoring marine specimens' health is mandatory. Traditional methods involving specimen capture and handling are invasive, stressful, and disruptive. Some techniques like underwater visual census or laser photogrammetry have been used for noninvasive data collection, but they have limitations and biases. The application of stereo-video photogrammetry through the use of diver-operated stereo-video systems (stereo-DOV) is a noninvasive method that overcomes these challenges, providing highly accurate measurements. It has become popular for species monitoring, studying anthropogenic impacts, and assessing length distributions. However, this technique is still uncommon and barely reported in aquarium settings. This study describes an innovative pilot study targeting multiple species carried out in a Public Aquarium, using a low-cost house-made device. The results revealed that measuring more than 100 individuals in approximately 1 day's work is possible. Total and fork lengths were estimated using specific software for 31 teleost and 16 elasmobranch species and compared with real measurements for the available species. Despite technical limitations that must be reviewed for application in future studies that resulted in high root mean square (RMS) values (> 20 mm), differences between methodological approaches revealed a minimal discrepancy (1.37%-5% in large sharks and rays and 1.8%-5.5% in teleost fish). This technique has time and cost requirements, but might represent a major advance in husbandry and in the contribution to conservation that ex situ studies can provide.

Sex differentiation via the relationship between some morphological measurements of Mystus albolineatus caught from Cai Rang - Can Tho and Long Phu - Soc Trang

This study supplements the gender determination methodology based on the relationship of some morphological indicators in Mystus albolineatus. A total of 229 specimens were caught by trawl nets at Cai Rang – Can Tho and Long Phu – Soc Trang in four months from April to July 2023. After collection, the samples were transferred to the laboratory to determine the total length (TL), standard length (SL), eye diameter (ED), eye distance (DE), body height (BH), head length (HL), and mouth diameter (MD) before surgery to determine the sex based on the gonad. The results showed that the TL-SL regression relationship could be used to determine the sex of this fish. Besides, TL-BH and TL-MD growth relations were relatively balanced in females versus males. In addition, based on SL, DE, and MD, it was also possible to determine whether the sampling time was the wet or dry seasons. These findings form the basis for the initial study of the biological characteristics of this fish in the Mekong Delta.

Ancient Fishing Strategies for the Extinct Thicktail Chub (Gila crassicauda) in the Sacramento-San Joaquin Delta

ABSTRACT Now extinct, Thicktail chub (Gila crassicauda) was endemic to central California and was a key component of local fisheries before the 1800s. Little is known about their biology, behavior, ecology, or role in precontact Native American fisheries. Archaeological sites contain large numbers of thicktail chub bones and represent a key source of data to fill our considerable gap in knowledge. We developed regression equations to convert thicktail chub skeletal elements to estimates of standard length (SL). Bones from two contemporaneous precontact Late Period (ca 700 -200 cal BP) sites, CA-CCO-138, and CA-CCO-647, in the Sacramento-San Joaquin Delta, show that precontact thicktail chub achieved a maximum standard length (SL) of 306 mm. Bone size distributions suggest spearing was the most likely capture technique, likely during a spring-summer nearshore fishery. The results contribute vital information to thicktail chub historical ecology and their key role in precontact Indigenous fisheries.

Life history of Mexican species of the genus &lt;i&gt;Tlaloc&lt;/i&gt; (Cyprinodontiformes, Profundulidae)

Fish of the genus Tlaloc are distributed from southern Mexico to Central America and are a distinctive example of the endemic fauna of the Mesoamerican highlands, which has been scarcely studied in Mexico. The present study provides basic life-history data for the species Tlaloc hildebrandi, T. candalarius, and T. labialis, which are native to the headwaters of the Grijalva-Usumacinta basin in southeastern Mexico. We collected 918 specimens to determine their Length-Weight Relationship (LWR), Relative Condition Factor (Kr), sex ratio, Gonadosomatic Index (GSI), fecundity, and size at first sexual maturity. Both sexes of all species had positive allometric growth, except for T. candalarius females (isometric). Mean Kr and sex ratio values differed significantly among species. Females’ GSI values differed significantly among species but were highest during the dry season in all three species. Absolute fecundity was positively correlated with standard length and weight. Sexual maturity was reached at different lengths among species. Based on these results, we suggest that all three species present an opportunistic life strategy, which is very common in fish of the order Cyprinodontiformes. These results represent a first contribution on the life-history of this group of fish and provide basic information that is fundamental to ensuring their conservation.

Understanding freshwater to marine transitional scale growth in Atlantic salmon (Salmo salar)

Abstract The first marine circulus is the scale feature associated with marine entry and has been used to support research evaluating the relationships between size, growth, and survival for Atlantic salmon. Ambiguity in growth rates and circulus deposition during the transition from freshwater to the marine environment leads to difficulty in the correct identification of the first marine circulus. In this study, scale growth occurring after the last freshwater annulus (plus-growth) was characterized for Atlantic salmon smolts migrating out of the Narraguagus River in Maine. Plus-growth was present in over 95% of scales from smolts leaving the river and represented on average 12.2% of total freshwater growth. These findings suggest plus-growth presents a significant source of error in growth analyses, if ignored, and the characterization of this scale feature helps to inform accurate identification of marine entry for future studies. Run day was a driver of plus-growth, suggesting extended freshwater residency provides opportunity for growth prior to smolt emigration. The negative association between fork length and plus-growth suggests smaller smolts that delay migration are demonstrating compensatory growth. Cumulative air temperature was positively associated with plus-growth, suggesting warming spring temperatures driven by climate change may influence size at marine entry for smolts.

Morphometric trait normalization, cluster analysis and molecular phylogenetic analysis in delimiting sympatric Neolissochilus hexastichus and N. hexagonolepis in Umngi River, Meghalaya (India)

Aim: To assess the ability of an integrative approach comprising multivariate morphometric data analysis and mitochondrial cytochrome oxidase subunit I (CO I) sequence divergence analysis in delimiting sympatric Neolissochilus hexastichus (McClleland, 1839) and N. hexagonolepis (McClleland, 1839) mahseer populations in River Umngi, Meghalaya. Methodology: Authoritative descriptions of mahseers were referred during the sampling of 40 individuals from River Umngi, Meghalaya. Multivariate morphometric data were normalized with respect to standard length. The normalization procedure maintained the particular shape factor for each sample. Normalised data were subjected to hierarchical clustering on principal components Analysis (HCPC) for grouping samples according to morphometric features. Genetic affinities based on CO I sequence divergence were assessed by Bayesian Inference (BI) and Automatic Barcode Gap Discovery (ABGD) protocols. Results: The normalization protocols removed the variations in traits due to body size effects and facilitated the identification of allometric traits. HCPC analysis revealed morphometric features that had a significant impact on clustering. Nine N. hexagonolepis and 13 N. hexastichus individuals were identified by integrative morphological and molecular phylogenetic approach. The remaining 18 individuals had incongruence in their memberships in the morphometric and phylogenetic clusters. Interpretation: The integrative approach, apart from delineating N. hexagonolepis and N. hexastichus congeners, highlighted the need to include nuclear genetic markers in future studies for confirming the presence of natural hybrids in sympatric populations of Neolissochilus mahseers. Key words: Cluster, Morphometric, Neolissochilus, Normalization, Phylogenetics

Profiling growth performance, insulin-like growth factors (IGFs), and IGF-binding proteins (IGFBPs) in rainbow trout lacking IGFBP-2b.

Insulin-like growth factor binding proteins (IGFBP) regulate insulin-like growth factor (IGF) signaling, but IGFBP-specific functions are not well characterized in fishes. A line of rainbow trout (Oncorhynchus mykiss) lacking a functional IGFBP-2b was produced using gene editing and subsequent breeding to an F2 generation. This loss-of-function model (2bKO) was subjected to either continuous feeding or feed deprivation (3 wk) followed by refeeding (1 wk). During continuous feeding, the 2bKO line displayed faster specific growth rate for both body weight and fork length, higher feed intake, and reduced feed conversion ratio compared to a wild type (WT) line. However, loss of IGFBP-2b did not affect the feed deprivation or refeeding response in terms of weight loss or weight gain, respectively. Several components of the IGF/IGFBP system were affected by loss of IGFBP2b. Total serum IGF-1 in the 2bKO line was reduced to 0.5 - 0.8-fold of the WT line although the concentration of free serum IGF-1 was not affected. Gene expression differences include reduced abundance of igfbp1a1, igfbp1b2, igfbp5b2, and igfbp6b1 transcripts, and elevated igf2 and igfbp6b2 transcripts in liver of the 2bKO line. Collectively, these findings suggest that although IGFBP-2b is a carrier of circulating IGF-1 in salmonids, the presence of IGFBP-2a and compensatory responses of other IGF/IGFBP system components support an anabolic response that improved growth performance in the loss-of-function model.

Power handling in a highly-radiative negative triangularity pilot plant

Abstract This work explores detailed power handling solutions for a class of high-field, highly-radiative negative triangularity (NT) reactors based around the MANTA concept [Rutherford et al. (2024)]. The divertor design is kept as simple as possible, opting for a standard divertor with standard leg length. FreeGS is used to create an equilibrium for the boundary region, prioritizing a short outer leg length of only ∼50 cm (∼40% of the minor radius). The UEDGE code package is used for the boundary plasma solution, to track plasma temperatures and fluxes to the divertor targets. It is found that for PSOL = 25 MW and nsep = 0.96 × 1020 m−3, conditions consistent with initial core transport modeling, little additional power mitigation is necessary. For a fixed impurity fraction of just 0.13\% Ne in the plasma, the peak heat flux density at the more heavily loaded outer targets falls to 7.8 MW/m2, while the electron temperature, Te, remains just under 5 eV. Scans around the parameter space reveal that even at densities lower than in the primary operating scenario, PSOL can be increased up to 50 MW, so long as a slightly higher fraction of extrinsic radiator is used. With less than 1% neon (Ne) impurity content, the divertor still experiences less than 10 MW/m2 at the outer target. Design of the plasma-facing components includes a close-fitting vacuum vessel with a tungsten inner surface as well as FLiBe-carrying cooling channels fashioned into the VV wall directly behind the divertor targets. For the seeded heat flux profile, Ansys Fluent heat transfer simulations estimate that the outer target temperature remains at just below 1550◦C. Initial scoping of advanced divertor designs shows that for an X-divertor, detachment of the outer target becomes much simpler, and plasma fluxes to the targets drop considerably with only 0.01% Ne content.