Fin Length Research Articles

Albizzia pollen-inspired phase change capsules accelerate energy storage of packed-bed thermal energy storage system

Packed-bed thermal energy storage (PBTES) system using phase change capsules has been widely applied for thermal energy harvesting and management to alleviate unbalanced energy supply and demand problems. However, the slow thermal energy charging is always a daunting challenge limiting its fast development. Here, a bionic phase change materials (PCMs) capsule by mimicking the natural structure of albizzia pollen is proposed. The heat storage performance and economy of capsules with different internal fin structures are investigated numerically and experimentally. The thermal charging of pollen-type PCMs capsules is the fastest, whose melting time prominently reduces by 19 %, 24 %, 41 % and 61 % compared to the plate-type, ring-type, column-type, and pure PCMs capsules, respectively. That is because the contact area between the skeleton and the capsule wall is increased and the average distance between PCMs and the heat transfer surface is shortened. The pollen-type capsules exhibit the best economy with the exergy efficiency is improved by 15 % compared to pure PCMs capsule. By optimizing the ratio of fin length to radius (L/R) to 5/6, the melting time can be further reduced by 62 % and the exergy efficiency can be improved by 16 % owing to the enhanced heat transfer rate in the center of the pollen-type capsules. A PBTES system is further built based on optimized pollen-based capsules, and faster heat storage rate is successfully demonstrated in experiments. These results provide alternative solutions for optimizing PBTES systems and improving their thermal energy storage performances.

Heat Transfer Augmentation Using Duplex and Triplex Tube Phase Change Material (PCM) Heat Exchanger Configurations

The significance of latent heat thermal energy storage is more substantial when compared to sensible energy storage due to its higher energy storage capability. In this paper, heat transfer enhancement techniques for melting (charging) and solidification (discharging) by using external fins and internal–external fins for a phase change material (PCM) in duplex and triplex tube heat exchangers (DTHX and TTHX) are investigated numerically. A two-dimensional analysis is carried out using ANSYS Fluent for various configurations. Moreover, the effect of different critical parameters, number of fins, fin length, fin thickness, and the heat exchanger tube material are evaluated in terms of the total time of complete phase change of the PCM. Four cases are investigated; cases 1 and 2 are based upon a DTHX while cases 3 and 4 are TTHXs. By considering case 1 as a reference case, it is found that case 2 and case 3 reduce the total melting time by 48.76% and 90.12%, respectively. Case 4 achieves the shortest time for complete melting of the PCM, and the total melting time is decreased by 92%. Solidification behaviour for all four cases is also investigated. The novel configurations increase (doubled) the supply of heat transfer fluid (HTF) while at the same time significantly enhance the melting/solidification characteristics for all the cases without disrupting the convectional currents during phase change of the PCM. Tube materials with different thermophysical properties are also investigated with the heat transfer rate and melting time significantly improved with a high thermal diffusivity material. Moreover, the heat transfer is found to increase with fin length and fin thickness.

Evaluation of the solidification process in a double‐tube latent heat storage unit equipped with circular fins with optimum fin spacing

AbstractIn this study, the effect of fin number and size on the solidification output of a double‐tube container filled with phase change material (PCM) was analyzed numerically. By altering the fins' dimensions, the PCM's heat transfer performance is examined and compared to finless scenarios. To attain optimal performance, multiple inline configurations are explored. In addition, the initial conditions of the heat transfer fluid (HTF), including temperature and Reynolds number, are considered in the analysis. The research results show a significant impact of longer fins with higher numbers on improving the solidification rate of PCM. The solidification rate increases by 67%, 170%, 308%, and 370% for cases with 4, 9, 15, and 19 fins, respectively, all with the same fin length and initial HTF boundary condition. The best case results in a solidification time that is 4.45 times shorter compared to other fin number and dimension scenarios. The study also found that moving from Reynolds numbers 500 to 1000 and 2000 reduced discharging times by 12.9% and 22%, respectively, and increased heat recovery rates by 14.4% and 27.9%. When the HTF entrance temperature was 10°C and 15°C, the coolant temperature showed that the entire discharging time decreased by 37.5% and 23.1% relative to the solidification time when the initial temperature was 20°C. Generally, this work highlights that increasing the length and number of fins enhances thermal efficiency and the phase change process.

Investigation of the impact of fin number and length attached to an enclosure subjected to a magnetic field

In the current study, the heat transfer and entropy generation of an Al2O3CuO/water hybrid nanofluid in a square enclosure with a constant magnetic field is investigated and optimized after sensitivity analysis. Varying lengths of fins, three different configurations of single, double, and triple fins attached on the left hot wall of the enclosure are compared. The right wall is kept at a lower temperature, while the top and bottom walls are insulated. The configuration is taken into account as a categorical factor and the length of the fins is used as a numerical factor in the regression modeling. The d-optimal method is then used in sensitivity analysis and optimization. A two-objective optimization was conducted to minimize the entropy generation and maximize the heat transfer rate, at the same time. The findings indicate that using more fins, even if they are not long, can result in a 30% increase in heat transfer. Furthermore, with fewer fins yer longer, the heat transfer enhancement can still be achieved. Additionally, attaching more fins decreases the entropy generated by viscous dissipation.

Solidification of nanoparticle-based PCM in a fin-aided triplex-tube energy storage system for cooling applications

Accomplishing a better solidification rate to enhance the Thermal Energy Storage (TES) systems' performance is crucial. One such storage system is the Triplex-tube heat exchanger (TTHX), which is preferable due to its larger heat exchanger area that makes the phase change rate faster. The present study demonstrates a combination of different heat transfer enhancement techniques to improve the performance of the TTHX system. The heat transfer performance of the entire solidification process in the heat exchanger is numerically studied. The system is designed for low-temperature cooling applications with water as PCM placed in between the annulus region of the TTHX. Fins have been employed to enhance the low heat transfer rate due to the poor thermal conductivity of the water as PCM. The effect of incorporating maximum fin length between the annulus region on the discharging performance is evaluated. In this regard, two fin arrangements – attached and detached are investigated. The influence of different cooling methods, namely both-side, inside and outside, are evaluated for mentioned fin arrangements in terms of the required solidification time, liquid–solid interfaces, and heat transfer rate. The impact of including CuO nanoparticles on the thermal and flow structure under different volume fractions is investigated. The results demonstrate that detached fins perform superior under a given heat transfer fluid temperature among other fin cases. In comparison, both-side cooling expedites the process better than other cooling methods. Inclusion of 7% nanoparticles along with fins results in an even faster freezing process, which helps to reduce full solidification time in all cases by nearly 29% and 25% in attached and detached fins, respectively.

Thermo-hydraulic performance prediction for offset-strip fin heat exchangers using artificial neural networks

In this study, an artificial neural network (ANN) model was applied to predict the thermo-hydraulic performance of the offset-strip fin heat exchanger. The ANN model was used for predicting the thermo-hydraulic performance to improve the prediction accuracy and extend the applicable range compared to the results of using the empirical equations reported in previous studies. The main parameters of these empirical equations were fin height (0.134 < α < 0.997), fin length (0.012 < δ < 0.048), fin width (0.041 < γ < 0.121), and Reynolds number (120 < Re <104). In addition, the Fanning friction factor f and the Colburn factor j were considered as the outputs of the ANN model. The impact of the parameters on the thermo-hydraulic performance of the heat exchanger was quantitatively evaluated, and the prediction accuracy was improved over a wide range for the thermo-hydraulic performance generated by the ANN model. Thus, the results obtained using the ANN model agreed well with the experimental data over a wider range than possible for the previous empirical correlations, showing extremely high accuracy and validity of the ANN model in comparison to the empirical equations.

Magnetohydrodynamic double-diffusive mixed convection in a curvilinear cavity filled with nanofluid and containing conducting fins

This work numerically analyzes the mixed convective double diffusion of Fe3O4-water-based nanofluid in a tilt curvilinear lid-driven cavity studied under the effect of an inclined magnetic field. The horizontal upper wall is at a lower thermal and concentration gradient and moves toward the right. The side vertical walls and bottom walls kept adiabatic. Furthermore, two numbers of conducting fins are affixed to the inclined walls at high temperatures and concentrations. The finite element approach is implemented to analyze the considered variables: Richardson number (Ri), Hartmann number (Ha), Reynolds number (Re), Lewis number (Le), buoyancy ratio (N), magnetic inclination angle (α), nanofluid volume fraction (ϕ) as well as the fins length on the heat and mass transport phenomena. The results showed that the Nuavg and Shavg increase by increasing Reynolds number, the nanoparticles volume concentration, and the fin length, while they decrease by increasing Hartmann number. When Ri is small, Nuavg rises with the increasing magnetic field inclination, but when Ri is high, the inclination angle works adversely. On the other hand, the Shavg increases with the rise of the magnetic field inclination for all Ri values. It can be seen also, when Lewis number increases, the Nuavg and Shavg values increase with increasing Ri and magnetic inclination angles.

Exploring tree‐like fins for enhanced latent heat storage performance

AbstractThis study examines how tree‐like fins can be used to improve the phase‐change process of Latent Heat Storage (LHS) systems. ANSYS‐Fluent was utilized to predict the temperature distribution and the time‐evolution of the phase‐change process. A Heat Transfer Fluid (HTF) at 353 K was used for the charging, and 293 K for the discharging process in a shell and tube configuration. Results showed that tree‐like fins provide superior thermal performance compared to straight fins (base case) for both charging and discharging. The thermal performance is enhanced when employing short fin lengths relative to their maximum size at each branch (small αn values). This reduces the temperature gradients within the PCM without increasing the volume occupied by the fins within the LHS system. In addition, decreasing αn values increases the heat transfer area between the fins and Phase‐Change Material (PCM). Designs with two bifurcations achieved a notable increase in their heat transfer area, accelerating the phase‐change process compared to the base case.

Scrutiny of melting rate of phase change material in a four petals cavity with internal branch fins under magnetic field

This paper attempts to conduct the numerical simulation of the behavior of a phase change material (PCM) in a four petals enclosure with internal fins. The enthalpy-porosity method was used to simulate the thawing process. Two new enclosures with the different arrangements of the fins have been considered. The simulation results for the new finned geometries have been compared with those of the simple double-tube geometry. The effects of fin length (FL), angle between the fins (ABF), non-uniform magnetic field, Stefan number on the PCM melting process (PCM-MP) have been inspected. Results display that the average liquid fraction for new no-fin geometries has increased by about 14% compared to the simple double-tube. In both storage enclosures, the PCM-MP has increased by enhancing FL and falling ABF. ABF = 40° is about 18.7% higher melting performance. Also, the use of non-uniform magnetic field and boosting its power improves the PCM-MP about 10%. Increasing Stefan number augments the PCM-MP by about 15%. The material of the fins has a momentous result on the PCM-MP.

A bi-directional flow-energy harvester

Due to a rapid decrease in fossil fuel resources and ever-growing carbon emissions, clean energy is urgently needed as a vital solution. In the past two decades, harvesting clean energy from ambient environment has attracted much attention. Flow induced vibration and energy harvesting performance of a cylinder with fins attached were investigated. Four configurations were studied: a plain cylinder, a cylinder with two windward fins, a cylinder with two leeward fins, and a cylinder with four fins. These four cylinders were tested in a water channel with a reduced velocity ranging between 2 and 25 and a Reynolds number ranging between 1500 and 11 400. It was found that the two-windward-fin cylinder underwent galloping, exhibiting much larger vibration amplitudes and a much broader operational velocity range, whereas the two-leeward-fin cylinder only underwent weak vortex-induced vibrations. By attaching both two windward and two leeward fins to the cylinder, a bi-directional flow-energy harvester was implemented, which outperformed the plain cylinder with much larger vibration amplitudes and a much broader velocity range. More importantly, due to the geometric symmetry, it is able to harvest flow energy from two opposite directions. A tuned-mass-damper system was then attached to the four-fin cylinder for the purpose of demonstration. Within the current flow speed range, the maximal voltage and power outputs are about 7.37 V and 1.81 μW, respectively, about 2.7 and 7.2 times the plain cylinder's peak values. The effects of flow incident angle and fin length were also studied. Numerical simulations were also conducted to provide a detailed information of flow and pressure to uncover the underlying physics. This bi-directional flow-energy harvester is a suitable candidate to operate at sites where the flow periodically switches its directions, such as in tidal flows.

Multi-objective optimization of an offset strip fin heat exchanger for waste heat recovery in electric vehicles

To increase short driving range of electric vehicle, it is important to reduce power consumption of heat pump system. In this study, an offset strip fin heat exchanger with perpendicular flow is investigated to improve the performance of an electric vehicle heat pump using waste heat. The correlations of the Colburn and friction factor are developed using the experimental data. The simulation results are compared to the experimental results and are validated within temperature and pressure errors of 1.51% and 1.55%, respectively. A multi-objective optimization is performed to maximize the thermal–hydraulic performance of the offset strip fin heat exchanger with six independent design variables via the approximation-assisted optimization technique. The five optimal designs exhibit a 3.7% increase in the heat transfer rate and a 42.1% decrease in the pressure drop for the main simulation condition. Sensitivity analysis and parametric studies are conducted to analyze the effects of each design variable. The results reveal that the fin wrinkle angle, fin height, fin length, and fin spacing had a significant impact on the thermal–hydraulic performance of the offset strip fin heat exchanger.

Minimally Invasive Collection of Biometric Data Including Maturation Stage on European Eel Using Photography

AbstractIn response to the severe decline of the European Eel Anguilla anguilla stock in recent decades, various data frameworks and research efforts toward improved management rely on the availability of site‐specific biometric data. At the same time, scientists are obligated to minimize the negative effects (stress, harm, and sacrifice) of their samplings on individuals and the population without compromising data quality. In‐field methods for biometric measurements must be quick, precise, and practical for the user. Essential information that is typically required in (large‐scale) eel monitoring programs includes body length, mass, sex, and maturation stage. As live eels are difficult to handle, individuals are typically anesthetized or killed (and sometimes stored frozen to postpone measurements) to obtain the necessary biometrics. The primary purpose of this paper was to explore the suitability of a nonlethal method based on photography for obtaining essential biometrics and maturation stage from live European Eels A. anguilla in a timely manner. In addition, we evaluated the relative accuracy of measuring the parameters that are necessary for assessing maturation stages in eels after defrosting and examined the necessity of correcting for potential shrinkage of eyes and pectoral fin. Both procedures were compared against a standard reference of measurements from freshly killed eels. We found that the minimally invasive method using alive measurements of eels' body length and mass together with digital measurements of eyes and pectoral fin from photographs had the highest agreement for maturation stage outcome with the fresh reference. Our results further reveal the necessity of correcting for shrinkage of eyes and pectoral fins (in addition to length and mass) after freezing to maximize reliability in stage classification. Consequently, we provide specialized formulae to apply shrinkage corrections for eye diameter and pectoral fin length.

Design optimization of a novel annular fin on a latent heat storage device for building heating

The poor heat transfer performance of the heat exchanger leads to low heat storage efficiency of the latent heat storage device. To improve the heat transfer performance of the heat exchanger, a novel annular fin with inclined angle is proposed to enhance heat transfer of the heat exchanger. 12 fins with different structural parameters are designed and welded to the inner tube wall of the heat exchanger. The simulation model is in good agreement with the literature and the model is considered to be reliable. Based on the enthalpy-porosity model, the liquid fraction, temperature distribution, melting front, energy storage density and heat storage rate were used to compare and optimize the structural parameters of the annular fins. Results demonstrated that the difference in complete melting time due to the number of fins, fin arrangement, fin length and fin angle were 43 min, 85 min, 17 min and 10 min, respectively. The fin arrangement was the most significant in reducing the heat storage time. Compared to N = 4 and uniformly distributed fins, non-uniformly distributed fins reduced the total melting time of stearic acid by 53.13 % and 20.54 %. To be conclusive, the addition of non-uniformly distributed annular fins with 70° inclination enhanced the heat transfer in the heat exchanger and saved a significant amount of heat storage time.

Sexual dimorphism and reproductive biology of Cephalocassis borneensis (Siluriformes: Ariidae), a paternal mouth-brooding fish in the Mekong River.

Information on the reproductive biology of fish species is essential for fisheries management, conservation and culture potential assessment. Therefore, this study aimed to understand the sex-based morphological differences and reproductive characteristics of Cephalocassis borneensis, an ariid species with a rapid decline of wild populations. Fish samples were collected monthly from local fishermen (n = 1092) in the Vietnamese Mekong River over a year. Morphological analyses revealed that sexual dimorphism was observed in mature, but not immature, fish. The length at first maturity (Lm ) was smaller for males (11.5 cm) than for females (12.5 cm). Mature males had larger head length and pre-pectoral distance than mature females, increasing the space for oral incubation of fertilized eggs and larvae in males. Conversely, females were larger in three head parameters (head angle, head width and head depth) and three abdomen parameters (body deep, ventral fin length and distance between pectoral and ventral fin) involved in ovary development. Paternal mouth-brooding behaviour is an important reproductive strategy in C. borneensis to increase offspring survival. Monthly variations in gonado-somatic index and condition factor (K) and the presence of maturation stages indicated that C. borneensis spawns year-round, mainly in the rainy season from June to October. This species' fecundity was relatively low, from 10 to 31 eggs per female of quite large sizes (about 7.30 ± 0.68 mm in diameter). Besides, non-functional oocytes (hyaline eggs) of smaller size (<3 mm) were found in the females' ovaries. Low fecundity with large eggs and paternal care indicated that the species is an equilibrium strategist. These characteristics are critical in developing ariid species conservation plans, such as setting the time and mesh-size for fishing, and domestication programmes in artificial conditions.

A comparative numerical study about the impact of rectangular and T shaped fins on melting of PCM in a rectangular enclosure

A comparative numerical study is performed on the melting of RT42 phase change material (PCM) in a rectangular enclosure using two basic fin geometries: a regular fin and a flanged fin (T-shape) having a constant fin area. Five cases of each fin type, representing ten double fin arrangements, based on an upper (Lu) and lower fin (Ld) length ratio were examined. Hence, for cases I(I’), II(II’), III(III’), IV(IV’), and V(V’), theLu/Ld ratio is 1, 1.5, 4, 0.67, and 0.25, respectively. Furthermore, two more cases (VI and VII) with a single flanged fin at the upper and lower position were considered with flanged (Lf) to web (Lu, d) ratio of 0.136. Five performance indicators were employed: total melting time (tm), total stored energy (Et), average Nusselt number (Nu¯), mean power (Pm), and cost per mean power (Cpw) to evaluate the effect of fin geometry on the heat transfer mechanism governing the melting of PCM. An enthalpy-porosity model governed the phase change process. The mathematical models were simulated and verified against the reference theoretical results in ANSYS 2020 R2, CFD software. Mesh and time independent studies were also performed, and a time step of 0.1 s and 26,026 quad cell elements were recommended for a balanced computational accuracy and cost. The result shows that for the double fin arrangement cases, a decrease in the tm was observed as the Lu/Ld ratio was decreased. Case V, with the regular fin of Lu/Ld ratio 0.25, has the maximum melting rate and completely melts the PCM in 3696 s. However, the single flanged fin at the lower position (case VII) melts the PCM entirely in 2940 s, which is 41.2 % and 20.45 % faster than case I and V, respectively. Each case stores approximately the same amount of energy over time. However, for case VII, a high latent and sensible heat absorption rate was observed, followed by cases V and V’. Also, the Pm for case VII is 163 W, 71.32 %, and 25.66 % higher than case I and V, respectively. For the cost analysis, Cpw is employed, a ratio of the system’s total cost ($ 43.2) to the Pm. The Cpw for case VII is 0.27 $/W, 40 %, and 18.2 % less than case I (0.45 $/W) and V (0.33 $/W). The above result indicates that the double fin geometry can be replaced with a single flanged fin system for a high melting rate and low Cpw. Hence, a further study is required based on flanged to web ratio (Lf/Ld) and the positioning of the single flanged fin. A minimum tm (2806 s) and Cpw (0.252 $/W) were obtained for the Lf/Ld ratio of 0.25, placed 15 mm above the bottom of the container.

A general correlation for flat tube-and-fin radiator based on parametric CFD analysis

The work numerically predicted a Fin-and-flat tube heat exchanger with an experimental validation. The unit was firstly redefined as five basic modules. Based on L9(34) orthogonal tests involving vertical fin spacing, horizontal tube spacing, fin length, and fin thickness, the formed overdetermined equations were solved and discussed by regression and F significance test. After a derivation, the general correlation was compared with published, fitted, and numerical results. Finally, its applicable range was numerically clarified. It is found that the maximum 3.62% error of heat transfer coefficient and 4.51% error of pressure loss, respectively. The fitted correlation can predict over 88.9% of j under 3.10% average error and 96.30% of f under 2.33%. 2.6-4.0 mm vertical spacing, 16-100 mm fin length, 5-8 mm horizontal spacing, 0.03-0.09 mm fin thickness, 3-4.4 mm hydraulic diameter, 1-5 tube rows, and Reynolds number of 550-3290 might work for the efficient deployment of the general correlation.

Study on melting and solidification performances improvement of phase change material using novel branch fin structure

A novel fin structure was proposed to improve the heat transfer characteristics of triple-tube latent heat storage system (TTLHSS). Ansys Fluent software is used for two-dimensional numerical calculation, and the model adopts melting/solidification model. The innovation of this paper is to develop a new type of fin that can simultaneously improve the solidification and melting process of PCM and optimize the structure of the new fin so that it can significantly shorten the time required to complete a heat storage and release cycle. Initially, the melting process of the case without fins and the case with new fins were compared. It was observed that compared with the case without fins, the melting and solidification time was shortened by 67.7 % and 74.8 %, respectively. Then the effects of the thickness, the length ratio, and the angle of the new fins on the melting and solidification process of PCM were studied. The liquid fraction contour of PCM in different cases and the liquid fraction curve of PCM with time were analyzed. The results show that the addition of new fins can significantly improve the heat storage and release rate of PCM in TTLHSS. Compared with rectangular fins, melting time and solidification time are reduced by 32.7 % and 52.9 % respectively. The new fins distribute the fin volume in the central area of the PCM which is difficult to melt, which improves the melting and solidification speed of the PCM and makes the overall rate more uniform. Finally, the geometric parameters of the fins are optimized by the response surface method (RSM), and the fin configuration with the cross fin thickness of 0.8 mm, the fin length ratio of 1, and the fin angle of 63.1° is optimal for shortening the total time. At this time, the time required to complete a heat storage and release cycle is reduced by 84.5 % compared with the case without adding fins. The corresponding regression equation is also obtained, which provides a basis for the design of fins.

Morphometric Analysis of Different Parameters for Labeo boga from Head Panjnad, Alipur, Punjab, Pakistan

This study was designed to analyze the external morphometric characteristics of Labeoboga from Head Panjnad, Alipur, Punjab, Pakistan. About 48 specimens were collected and examined to address the growth patterns of the species under study for the first time, together with their morphometric characteristics for the analysis of morphological characters. The analysis of the present results for the length-weight relationship revealed that the value of regression coefficient ‘b’ was <3.0 according to the cube law, showing a negative allometric growth pattern (b = 2.710). Additionally, a highly significant positive correlation (r > 0.931; P < 0.05) was recorded for the correlation value ‘r’ among weight and length. A linear correlation was observed among 11 morphometric characters vs total length (TL), which revealed a highly significant correlation between total length vs standard length, body weight, fork length, dorsal fin length, body girth, body depth, anal fin length, and pectoral fin length, respectively. While, a moderate correlation was recorded between total length vs head length, eye diameter, and caudal peduncle length. Furthermore, the same trend was observed in the correlation significance between total body weight and other morphometric characters. The current study would be helpful for ichthyologists and zoologists in comparing different morphometric characteristics of Labeoboga.

Optimization of melting performance of a heat storage tank under rotation conditions: Based on taguchi design and response surface method

The melting performance of a rotating triplex-tube latent heat thermal energy storage unit is studied by numerical simulation method. The Taguchi design and response surface method are applied to its optimized design. Firstly, the Taguchi design method is used to quantitatively reveal the specific effects of fin distribution, fin number, and fin material on the melting performance of the unit. Compared with all-inner tube-fin or all-outer tube-fin structures, the melting time of alternating inside and outside fin structures is shortened by 52.64% and 32.42%, the average heat absorption rate is greatly increased by 105.56% and 47.26%, and the total heat is reduced by 2.64% and 2.17%, respectively. Then, the response surface method is applied to the eight alternating fins obtained by the Taguchi design, and the effects of fin length, width, and rotation angle on the melting time and average heat absorption rate of the unit are studied. Compared with the original structure, the optimal structure reduces the total melting time by 7.37% and increases the average heat absorption rate by 7.23%. The geometric parameters’ interaction with the relevant target response is studied, and the corresponding fluid-structure interaction equation is fitted. Finally, the melt growth phenomenon near the wall is found in the initial melting stage of the optimized model by mechanism analysis.

Taxonomic and Otolith Shape Parameters of Nine Sympatric Catfishes Commercially Harvested in Pakistan

Abstract Accurate reorganization of harvested species is essential for appropriate fisheries monitoring but often unnoticed. In this study, an attempt was made to provide an accurate species description based on fish taxonomy and otolith shape parameters of nine sea catfishes living in Pakistan. The lapillus, the largest otolith of catfishes, includes the position of the umbo, the structure of the anterior mesial projection (amp), the incisura linea basalis (ilb) and sulcus lapilli marks (slm) in nine ariid catfishes were evaluated. Discriminant function analysis was performed using twenty-two morphometric parameters showed significant variations between the length of the maxillary barbel, adipose length and preorbital length, which were highlighted as basic discriminating characters. Species without barbells, such as Batrachocephalus mino and Osteogeneiosus militaris, were found to be distant. The taxonomic characters of the genera Netuma and Plicofollis overlapped due to a short adipose fin length. Nevertheless, species Arius arius, Sciades sona and Nemapterxy caelatus differed in a moderate adipose fin length. The preorbital length of Netuma bilineata has a short and rounded snout, while N. thalassina has a long and pointed snout, which is a distinguishing characteristic of both species. The coincident use of fish taxonomy and otolith shape parameters is an effective tool for catfish identification could be helpful in appropriate fisheries sampling programs and management in Pakistan whenever implemented.