Fin Base Research Articles

Phenotypic Characteristics of the Clupeid Fish Tenualosa ilisha (Family: Clupeidae) collected from Manjhand Vicinity, Pakistan

Thirteen body proportions of the clupeid species, Tenualosailisha were investigated from Manjhand locality on the Indus River, Pakistan. Negative allometricgrowths for all morphometric traits examined were attained. The highest value of ‘b’ coefficient obtained was at its highest level for fork length (0.8834) and its lowest value for eye diameter (0.0398). The correlation coefficient value (R2) was at its lowest value for the relationship of the pectoral fin length-total fish length (0.46), the medium value of 0.77 and 0.80 were obtained for dorsal fin base length and anal fin base length respectively, while the highest value of 0.99 was attained for the relationship of both fork and standard lengths-total length and 0.98 for caudal peduncle length followed by 0.94 for the relationship of postorbital length-total fish length. The present report provides data to fishery biologists on body proportions of T. ilisha from the Indus River valley, Pakistan to support in development of management policies for this fish species.

A new species of Cetopsis from the Guiana Shield (Siluriformes: Cetopsidae: Cetopsinae).

A new species of Cetopsis is described from Guiana Shield drainages in Guyana and Suriname. The new species is found in the Konawaruk River and tributaries, Essequibo River basin, Guyana, and in the Mauritie Creek, tributary to the Tempati River, upper Commewijne River basin, Suriname. The new taxon can be distinguished from all congeners by a combination of features: dark spots on sides of the body eye-sized or larger, dark, bilobed patch at the base of the caudal fin, absence of a dark humeral spot, absence of dark pigmentation along the fin-membrane posterior to the first dorsal-fin ray, dark pigmentation at the base of the dorsal fin, dark spots extending ventrally to the bases of anal-fin rays, and 41 total vertebrae with 28 caudal vertebrae. Data on internal anatomy of the new species were incorporated into a previously-published phylogenetic analysis and resolves the position of the new species as the sister group of C. motatanensis, from Lago Maracaibo basin. The new Cetopsis is the first species of the genus known to occur exclusively in the Guiana Shield.

Optimization of Horizontal Rectangular Fin Heat Sink: a CFD with Response Surface Analysis and Parametric Study

In this article, a CFD analysis is performed on rectangular fin heat sink, which is used for electronic cooling applications. A steady-state heat transfer through natural convection is considered in this model. It focuses on thermal analysis of rectangular heat sink with aluminum as a material, by varying different parameters like temperature difference between fin base temperature (53–105 °C) and ambient temperature (20 °C), fin spacing (2–20 mm), fin height (25–100 mm), fin length (2–100 mm) and fin thickness (1–5 mm). The 3D elliptic governing equations of laminar flow and heat transfer are solved through the CFD tool ANSYS Fluent 15. Initially, a parametric study of fin is performed for obtaining orthogonal effect of input parameters on heat transfer coefficient (HTC) at fin base temperature 53 °C. Based on the parametric study, range of parameters is set for performing design of experiments (DOE) using ANSYS Design explorer 15. Response surface is generated between the geometrical fin parameters and HTC using DOE. Multi-objective genetic algorithm optimization is performed with the objective to maximize heat flux and HTC. Optimized values of geometrical parameters for maximum heat transfer are predicted using response surface.

Cabdio crassus, a new species of cyprinid fish (Teleostei: Cyprinidae) from the Kaladan River of Mizoram, India.

Cabdio crassus, a new fish species, is described from the Kaladan River in Mizoram, India. The new species is distinguished from all its congeners by having a ventral keel extending from the middle of the chest, between the posterior base of the pectoral fin and along the abdomen up to the anus (vs. more or less keeled median scales from mid-point of abdomen between posterior base of pelvic fin up to anus in all other Cabdio) and 11½-12½ branched anal-fin rays (vs. 7 in C. jaya and 9 in both C. morar and C. ukhrulensis). It is further distinguished from C. morar and C. ukhrulensis by possessing more lateral-line scales (45-51 vs. 38-42 in C. morar and 35-37 in C. ukhrulensis), more predorsal scales (20-23 vs. 17-18 in C. morar and 14 in C. ukhrulensis) and more lateral transverse scales (½7/1/3½ vs. 5/1/2 in both C. morar and C. ukhrulensis). It also differs from C. jaya in having fewer lateral-line scales (45-51 vs. 52-60), more lateral transverse scales (½7/1/3½ vs. 5/1/3) and more pharyngeal tooth-rows (3 vs. 2). Furthermore, the cytochrome c oxidase sub unit I (coi) gene sequence separates Cabdio crassus from all other Cabdio species (interspecies distance ranges from 7.8-12.3%). The anomalies observed among the GenBank sequences of the genus Cabdio are discussed and resolved.

Effects of temperature and water turbulence on vertebral number and body shape in Astyanax mexicanus (Teleostei: Characidae).

Environmental changes can modify the phenotypic characteristics of populations, which in turn can influence their evolutionary trajectories. In ectotherms like fishes, temperature is a particularly important environmental variable that is known to have significant impacts on the phenotype. Here, we raised specimens of the surface ecomorph of Astyanax mexicanus at temperatures of 20°C, 23°C, 25°C, and 28°C to examine how temperature influenced vertebral number and body shape. To increase biological realism, specimens were also subjected to two water turbulence regimes. Vertebral number was counted from x-rays and body shape variation was analysed using geometric morphometric methods. Temperature significantly impacted mean total vertebral number, which increased at the lowest and highest temperatures. Fish reared at lower temperatures had relatively more precaudal vertebrae while fish reared at higher temperatures had relatively more caudal vertebrae. Vertebral anomalies, especially vertebral fusions, were most frequent at the extreme temperature treatments. Temperature significantly impacted body shape as well, with fish reared at 20°C being particularly divergent. Water turbulence also impacted body shape in a generally predictable manner, with specimens reared in high turbulence environments being more streamlined and having extended dorsal and anal fin bases. Variation in environmental variables thus resulted in significant changes in morphological traits known to impact fish fitness, indicating that A. mexicanus has the capacity to exhibit a range of phenotypic plasticity when challenged by environmental change. Understanding the biochemical mechanisms underlying this plasticity and whether adaptive plasticity has influenced the evolutionary radiation of the Characidae, are major directions for future research.

A new species of Parotocinclus (Loricariidae: Hypoptopomatinae) from Rio Tocantins basin, Brazil.

A new species of Parotocinclus is described from the Rio Tocantins basin, Tocantins State, Brazil. The new species is distinguished from congeners by a combination of characters such as: (1) a unique pattern of body coloration with five transverse dark bars; (2) absence of an adipose fin or small platelet at typical adipose-fin region; (3) absence of conspicuous dark dots broadly distributed on the body; (4) absence of a triangular dark blotch at the anterior base of the dorsal fin; and (5) presence of a V-shaped spinelet.

Optimization of Rectangular Fins With Prime Surface and Bottom Convection

The main goal of this work is to obtain semi-analytical solutions for the geometric optimization of fins considering the presence of a primary surface. Optimized fin dimensions devoted to finned surfaces are already available in the literature; however, these solutions have as assumption a known fin base temperature. In contrast, in many practical situations, employed fins are attached to a primary surface that has restricted dimensions due to design requirements. In these cases, the primary surface dimensions are kept fixed and the known condition is a temperature or convective condition prescribed on the primary surface boundary. For such scenarios, to the best of our knowledge, there are no simple analytical expressions derived in the literature. Thus, reasoning on this main problem, in the present work, analytical optimum expressions are derived in order to deal with this kind of applications. The obtained analytical equations are subsequently compared with optimum results acquired from numerical calculations. In summary, both analytical and numerical results show a good agreement. The main contribution of this work is to provide closed solutions for the mentioned optimization problem, thus allowing the construction of simple charts, facilitating the corresponding fin design process.

A Review On Rectangular Heat Sinks Under Natural Convection

In the paper review of studies of heat sinks under natural convection is taken up. The discussions are mainly on experimental works carried out on rectangular fin arrays, optimization of heat sink dimensions and heat transfer enhancement. The geometries of heat sinks, fin spacing, fin height, fin length, fin thickness and fin material and base to ambient temperature difference are the important parameters on which heat transfer rate depends. So the design and optimization of the heat sink geometries becomes essential. It was found that the optimum fin spacing is ranging from 6.1- 11.9mm which gives maximum heat dissipation; the base to ambient temperature difference is 20-1500C. During most of the experimental work carried out a good thermal conductivity material which is cost-effective was chosen.

Psilotris vantasselli, a new species of goby from the tropical western Atlantic (Teleostei: Gobiidae: Gobiosomatini: Nes subgroup).

A new species of goby is described from submersible and scuba collections off Bonaire and New Providence Island, Bahamas. A molecular phylogenetic analysis of mitochondrial and nuclear genes confirms the placement of the new species within the genus Psilotris of the Nes subgroup of the Gobiosomatini. The new species is easily distinguished from congeners and morphologically similar species of Varicus by its unique coloration, which includes eight narrow, bright yellow bars on the trunk, each with a small orange spot centered on the lateral midline. In addition, the combination of the absence of scales on the head and body and the presence of modified ctenoid scales on the base of the caudal fin, branched pelvic-fin rays, and 15-16 pectoral-fin rays further differentiates the new species from other species of Psilotris and Varicus.

Lagoon shrimp goby, Cryptocentrus cyanotaenia (Bleeker, 1853) (Teleostei: Gobiidae), an additional fish element for the Iranian waters

Shrimp-associated gobies are burrowing fish of small to medium size that are common inhabitants of sand and mud substrates throughout the tropical Indo-Pacific region. Due to specific habitat preference, cryptic behavior, the small size and sampling difficulties, many gobies were previously overlooked and thus the knowledge about their distribution is rather scarce. This study presents lagoon shrimp goby, Cryptocentrus cyanotaenia , as additional fish element for the Iranian waters in the coast of Hormuz Island (Strait of Hormuz). The distribution range of lagoon shrimp goby was in the Western Central Pacific and eastern Indian Ocean. This species is distinguished by the several traits such as body elongate and compressed, snout truncate, body brownish grey color with 11 vertical narrow whitish blue lines on the sides, largely greenish yellow on head and mandible, head and base of pectoral fin with numerous short blue oblique broken lines and spots with markings on the head and snout. Providing data on C. cyanotaenia which is now widely distributed in the Indo-Pacific, would offer particularly valuable information on the biogeography of species.

Opsarius putaoensis, a new species of subfamily Danioninae (Actinopterygii, Cyprinidae) from the Irrawaddy River basin in northern Myanmar.

Opsarius putaoensis, new species, is described from the Mali Hka River, a tributary of the Irrawaddy River in northern Myanmar. For convenience of identification, Opsarius sensu Rainboth (1991) in Southeast Asia and India can be divided into two species groups based on the number of anal-fin rays: (1) the O. gatensis species group with more than 12 branched anal-fin rays, and (2) the O. barna species group with fewer than 11 branched anal-fin rays. The remaining species of the O. barna species group can be divided into two species subgroups by the presence or absence of barbels: (1) the O. chatricensis species subgroup without barbels, and (2) the O. barnoides species subgroup with one or two pairs of barbels. Opsarius putaoensis sp. nov. is a member of the O. chatricensis species subgroup together with O. chatricensis, O. arunachalensis, and O. barna. Opsarius putaoensis is most similar to O. chatricensis in overall appearance, including the number of vertical bars and color pattern, but it differs from O. chatricensis by the following characters: insertion of dorsal not reaching posterior end of pelvic fin base vs. reaching, vertical bars 6-7 vs. 7-8, vertical bars extending to the lateral line vs. not, branched anal-fin rays 9 vs. 10, branched pelvic-fin rays 7 vs. 8, branched pectoral-fin rays 12, rarely 11 vs. 11, circumpeduncular scales 12 vs. 14, and scale rows between dorsal-fin origin and lateral line 7-8 vs. 6. It is distinguished from all other species of the genus Opsarius by a combination of the following characters: barbels absent, dentary with parallel rows of tubercles, snout much shorter than eye diameter, mouth gape below anterior edge of orbit, body deep with depth 25.6-33.3% SL, pectoral and pelvic axial scales lobate, lateral line completely perforated with 35-38 scales, scale rows between dorsal-fin origin and lateral line 7-8, predorsal scales 15, circumpeduncular scales 12, branched dorsal-fin rays 7, branched anal-fin rays 9, branched pelvic-fin rays 7, insertion of dorsal not reaching pelvic-fin base, body with 6-7 vertical bars, extending to lateral line, and distal edge of dorsal fin black.

A parametric study on structural effects of hollow hybrid fin heat sinks in natural convection and radiation

This study investigates structural effects of hollow hybrid fin heat sinks (HHFHSs) under natural convection and radiation conducting parametric analysis. The HHFHS is a staggered array of hollow hybrid fins (HHFs) denoting hollow pin fins containing perforations near fin bases and integrated with radially-placed plate fins. CFD thermal models validated by measurements were utilized to explore structural effects of the HHFHS such as the fin spacing; number, width, and length of the radial plate fin; and the number of perforations. It is found that the surface area enhancement of the radial plate fin considerably improves the thermal performance of the HHFHS although it modestly deteriorates the mass-based performance. It is seen that the HHF spacing has stronger influence on the radiation heat transfer rate compared with other parameters. The result shows that the perforations enable internal channel flows resulting in an additional heat transfer enhancement.

Sexual dimorphism of Canthophrys gongota (Teleostei: Cobitidae) using landmark-based geometric morphometrics in the Atrai river of Bangladesh

Studies on sexual dimorphism of gongota Loach Canthophrys gongota (Local name: Pahari Gutum) was performed capturing them from the Atrai River of Dinajpur district in Bangladesh. Females had light blotches and patches with thick and rounded pectoral and pelvic fins while males having dark blotches and patches with thin and comparatively pointed paired fins. Body size, lengths of the anal fin and distances between the bases of pectoral, pelvic and caudal fins were significantly different (5.62 < F < 11.65, P ˂ 0.05) between the sexes of C. gongota. The expansion factors of mean thin-plate grids and vectors also showed that the head region of males was statistically different from females, whereas abdomen and tail of the females were considerably broader than those of the males. Both PCA (principal component analysis) and DFA (discriminant function analysis) plots showed morphologically little overlapping of landmark points which discriminated the females from the males. These findings are the first records on the sexual dimorphism of this rare species that would be baseline in a future study.
 Bangladesh J. Sci. Ind. Res.54(2), 187-194, 2019

Cobitis xui, a new species of spined loach (Teleostei: Cobitidae) from the Pearl River drainage in southern China.

A new spined loach of the genus Cobitis Linnaeus is described from the Buquan River, located in Guangxi Zhuang Autonomous Region, China. The species differs from other members of Cobitis in China by a combination of morphological characters, none of them unique: body depth 14.3‒18.4% SL; lamina circularis long and knife-shaped; Gambetta zones present on the dorsolateral sides of the body (L1‒L5); 8‒11 large transverse elongated blotches on L5; 9‒12 large transverse elongated blotches on L1; maxillary barbels longer than eye diameter; 4‒5 narrow rows of dark spots on the caudal fin; caudal fin with 14 branched rays; a rectangular spot slightly smaller than eye diameter on the upper side of caudal fin base; and caudal-peduncle depth 79.5‒93.1% its length.

How Big Is an Error in the Analytical Calculation of Annular Fin Efficiency?

An important role in the dimensioning of heat exchange surfaces with an annular fin is the fin efficiency. The fin efficiency is usually calculated using analytical expressions developed in the last century. However, these expressions are derived with certain assumptions and simplifications that involve a certain error in the calculation. The purpose of this paper is to determine the size of the error due to the assumptions and simplifications made when performing the analytical expression and to present what has the greatest impact on the amount of error, and give a recommendation on how to reduce that error. In order to determine the error, but also to gain a more detailed insight into the physics of heat exchange processes on the fin surface, computational fluid dynamics was applied to the original definition of fin efficiency. This means that a numerical simulation was performed for the actual fin material and for the ideal fin material with infinite thermal conductivity for the selected fin geometry and Re numbers from 2000 to 18,000. The results show that fin efficiency determined by numerical simulations is greater by up to 12.3% than the efficiency calculated analytically. The greatest impact on the amount of error is the assumption of the same temperature of the fin base surface and the outer tube surface and the assumption of equal heat transfer coefficient on the entire fin surface area. Using a newly recommended expression for the equivalent length of the fin tip, it would be possible to calculate the fin efficiency more precisely and thus the average heat transfer coefficient on the fin surface area, which leads to a more accurate dimensioning of the heat exchanger.

A new lightfish, †Vinciguerria orientalis, sp. Nov. (Teleostei, Stomiiformes, Phosichthyidae), from the middle Miocene of South Korea

ABSTRACTA new fossil species of miniature lightfish, †Vinciguerria orientalis, sp. nov., is described from the middle Miocene beds of the Duho Formation, South Korea. This is the second extinct species of this genus described from skeletal remains. The new Neogene species is very similar to recent congeners in its general appearance, morphometrics, and body proportions. It is characterized by a combination of the following features: 37–40 vertebrae, 13–16 dorsal fin rays, 13–17 anal fin rays, 13–16 photophores in the ventral series from the pectoral fin base to the pelvic (ventral) fin base, 14 or 15 photophores in the ventral series from the anal fin base to caudal fin base of the ventral series, ca. 26 gill rakers, and a caudal body part length of more than 30% of standard length. The main difference separating †Vinciguerria orientalis from all other representatives of the genus is the lack of fusion between hypurals 1 and 2 and hypurals 3 and 4 and the separation of the urostylar centrum from hypural elements. This caudal skeleton structure appears to be a transition link between the Paleogene and Neogene–Recent species of this evolutionary lineage.

Multivariate analysis of morphological traits of sexually mature <i>Sarotherodon galilaeus</i> (Linnaeus, 1758) in Ogun State Coastal Estuary, Nigeria

Morphological variation in sexually matured Sarotherodon galilaeus was assessed from commercial fishermen operating Iken brushpark – fish aggregating device in Ogun State coastal estuary, Nigeria. Fifteen morphometric features and nine meristic characters were analysed using both univariate and multivariate analyses between the sexes of the population. Univariate analysis showed higher mean values in most of the morphometric and meristic counts of the female population than the males, but significant differences (p<0.05) were recorded in total length, standard length, head length, pectoral ray and gill raker of the first arch. Two and four Principal components were extracted for morphometric and meristic characters with 78.702% and 63.428% total variances respectively. Sexual differences occurred in morphometric characters such as, eye diameter, body weight, head width, length of dorsal base and length of pectoral fin while meristic counts showed overlapping in spinous dorsal fin rays, pectoral fin rays, scales along lateral line, scales above lateral line and gill rakers on the first arch. Canonical Discriminant function revealed the heterogeneity of total length, pectoral fin rays and gill rakers on the first arch in both sexes and these features could be used for the identification of the fish. This study revealed that multivariate statistical tools are effective means of analysing data for proper taxonomy, conservation and management of fish stocks.Keywords: Morphological traits, Multivariate analysis, Sarotherodon galilaeus, brushpark, meristic characters

Retention of loop, monel, and passive integrated transponder tags by wild, free‐ranging Lake Sturgeon ( Acipenser fulvescens Rafinesque, 1817)

Tagging or marking of fish is instrumental to fisheries biologists and managers seeking to distinguish groups of fish, track movement or migration patterns, and monitor population characteristics. However, tag loss can inhibit the ability of biologists and managers to reach these objectives. The ability of Lake Sturgeon to live for long periods of time and reach large sizes, in combination with their dynamic spawning activity, requires tags to be retained under a variety of environmental and physically demanding conditions. This study evaluated tag retention of loop, monel, and passive integrated transponder (PIT) tags on wild, free‐ranging Lake Sturgeon in Lake Huron and the St. Clair – Detroit River System. Lake Sturgeon in this study were double‐tagged with both a PIT tag under one of the three anterior‐most dorsal scutes and an external tag (loop or monel) at the base of the dorsal fin. Fish were at large for up to 16 years. Overall, tag loss for PIT tags was 1% followed by monel tags at 12% and loop tags at 36%. Tag loss for loop tags was higher when the initial length of Lake Sturgeon tagged was smaller. Tag loss for monel tags increased with time at large but was not related to length at initial tagging. Monel tags left behind abrasion marks when attached to smaller Lake Sturgeon. PIT tag retention was higher than reported in previous studies that tagged other sturgeon species in different body locations. Monel tag retention was higher than other external tag types evaluated in previous studies while loop tags had similar retention rates to external tag types. Most previous studies on tag retention of sturgeon species were of shorter duration and conducted in laboratory settings, therefore loop tags may have performed more favorably during studies under short term laboratory settings. Results of this study suggest that PIT tags inserted below dorsal scutes represent a viable option for long‐term tracking of Lake Sturgeon. Monel tags attached at the base of the dorsal fin also seem to be a viable option relative to other external tag types, but should be limited to larger sturgeon as they can leave behind abrasion marks.

Molecular confirmation of Henneguya adiposa (Cnidaria: Myxozoa) and associated histologic changes in adipose fins of channel catfish, Ictalurus punctatus (Teleost).

Henneguya adiposa is one of ten known, closely related myxozoan species that parasitize a variety of tissue sites in the channel catfish, Ictalurus punctatus. Reported to specifically target the adipose fin, H. adiposa is not associated with morbidity or mortality, although detailed descriptions of its associated histologic pathology are lacking. The objective of this work was to confirm the presence of H. adiposa within fin lesions of affected channel catfish using DNA sequenced from histologic sections obtained by laser capture microdissection, as well as to describe pathologic changes induced by infection. The parasite formed large, white, elongate, nodular plasmodia that caused localized tissue damage and incited a granulomatous inflammatory response within a deep connective tissue layer at the base of the adipose fin. Myxospores released from ruptured plasmodia into adjacent tissue were observed to migrate superficially in tracts through the skin, indicating a portal of exit for environmental dispersal. Defects in the connective tissue layer created by ruptured plasmodia were infiltrated by granulomatous inflammation and fibroplasia, suggesting lesion resolution by scar formation over time. Sequencing of the 18S rRNA gene amplified from excised myxospores confirmed the myxozoan's identity as H. adiposa, with 100% similarity to the reference sequence from previous published work.

Hooked-Horn Sculpins (Pisces: Cottidae, Artediellinae) from the Miocene of Sakhalin Island, Russia

Two new species of the recent genera of hooked-horn sculpins (Pisces, Cottidae, Artediellinae) are described from Miocene deposits (Serravalian–Tortonian) of the Agnevo Formation, Sakhalin Island, Russia. This is the first record of fossil skeletal remains of members of the subfamily Artediellinae. The Miocene hooked-horn sculpins are similar to modern fishes of this subfamily in the main countable characters and body proportions, but differ in a number of primitive features, such as the presence of skin spinules, covering the body up to the caudal fin base, and the presence of spines on the posterior edge of the lateral line scales.