Caudal Peduncle Width Research Articles

Geometric morphometric analysis and meristic variations of Philippine populations of the crescent perch Terapon jarbua (Centrarchiformes: Terapontidae)

The crescent perch Terapon jarbua is a demersal and catadromous fish that is widespread in the Indo-West Pacific region. It is a commercially important species in the Philippines and other Asian countries. Morphological differentiation among populations of T. jarbua throughout Philippine waters was investigated using morphometric and meristic characters. A total of 609 crescent perch (428 male, 181 female) were collected from nine localities in the Philippines. Meristic analyses showed the highest significant differences among populations in the lateral line scale and gill raker counts. Morphometric analyses revealed significant differences in shape among the nine T. jarbua populations. Allometry was found to be independent of size differences. Morphological differences were detected in the head, lip, and caudal peduncle regions. Specimens from General Santos City and Navotas were the most morphologically distinct from each other, whereas specimens from Sariaya and Balayan had the most similar shape. These can be attributed to the latitudinal gradient of the localities. Sexual dimorphism was also detected as significant differences were found in the specimens' lip positions, anal fin spine positions, caudal peduncle width, lateral line scale counts, gill raker counts, and pectoral fin ray counts. These morphological and meristic variations could be attributed to differences in feeding habits because T. jarbua is an omnivorous fish with a broad diet and can be found across marine, freshwater, and brackish environments. Further investigation of its diversity is recommended through the evaluation of T. jarbua feeding habits and their habitat's physicochemical characteristics. Additional sampling of populations outside of the Philippines is also recommended.

FishShapes v1: Functionally relevant measurements of teleost shape and size on three dimensions.

Teleost fishes account for 96% of all fish species and exhibit a spectacular variety of body forms. Teleost lineages range from deep bodied to elongate (e.g., eels, needlefish), laterally compressed (e.g., ribbonfish) to globular (e.g., pufferfish), and include uniquely shaped lineages such as seahorses, flatfishes, and ocean sunfishes. Adaptive body shape convergence within fishes has long been hypothesized but the nature of the relationships between fish form and ecological and environmental variables remain largely unknown at the macroevolutionary scale. To facilitate the investigation of the interacting factors influencing teleost body shape evolution we measured eight functionally relevant linear traits on adult-sized specimens along with specimen mass. Linear measurements of standard length, maximum body depth, maximum fish width, lower jaw length, mouth width, head depth, minimum caudal peduncle depth, and minimum caudal peduncle width were taken in millimeters with calipers, or tape measures for oversized specimens. We measured these traits on a total of 16,523 specimens (1-3 specimens per species) at the Smithsonian National Museum of Natural History and took approximately 7000 person hours of data collection to complete. The data went through a three-step error-checking process to clean and validate the data and then species averages were calculated. We present the complete specimen data set, which encompasses approximately one-fifth of extant teleost species diversity, spanning ~90% of teleost families and ~96% of orders. The species and family names are compatible with the taxonomy used by FishBase and the order information with the phylogenetically informed taxonomy of Betancur-R and colleagues published in 2014. This dataset is licensed under Creative Commons CC0 1.0 Universal (CC0 1.0) but please cite this paper when using the data or a subset of it.

Segmentation and measurement scheme for fish morphological features based on Mask R-CNN

The morphological features of fish, such as the body length, the body width, the caudal peduncle length, the caudal peduncle width, the pupil diameter, and the eye diameter are very important indicators in smart mariculture. Therefore, the accurate measurement of the morphological features is of great significance. However, the existing measurement methods mainly rely on manual measurement, which is operationally complex, low efficiency, and high subjectivity. To address these issues, this paper proposes a scheme for segmenting fish image and measuring fish morphological features indicators based on Mask R-CNN. Firstly, the fish body images are acquired by a home-made image acquisition device. Then, the fish images are preprocessed and labeled, and fed into the Mask R-CNN for training. Finally, the trained model is used to segment fish image, thus the morphological features indicators of the fish can be obtained. The experimental results demonstrate that the proposed scheme can segment the fish body in pure and complex backgrounds with remarkable performance. In pure background, the average relative errors (AREs) of all indicators measured all are less than 2.8%, and the AREs of body length and body width are less than 0.8%. In complex background, the AREs of all indicators are less than 3%, and the AREs of body length and body width is less than 1.8%.

A new species of the catfish genus Trichomycterus (Teleostei: Siluriformes: Trichomycteridae) from the Paraná basin, Central Brazil

Trichomycterus giarettai, new species, from a small river in Cumari municipality, Central Brazil is described. It is hypothesized to be closely related to species of T. brasiliensis complex by possessing the opercular odontodes disposed obliquely on the patch. Trichomycterus giarettai is diagnosed by the distribution of infraorbital pores, body width, caudal peduncle width, number of vertebrae, branchiostegal rays, dorsal and ventral procurrent rays, opercular and interopercular odontodes, length of the nasal barbels, and pelvic fin insertion.

Morphological differentiation among migratory fish species from the Paraná River basin

This study characterized the morphological differences among migratory fish species from the Paraná River Basin. A total of 177 adult fish of Leporinus elongatus, Leporinus macrocephalus, Prochilodus lineatus, Salminus brasiliensis, Pimelodus maculatus, Pinirampus pirinampu, Pseudoplatystoma corruscans, Pterodoras granulosus, and Rhaphiodon vulpinus were sampled in the Canal da Piracema, a fish passage system at Itaipu Dam, Paraná River. The migratory species were analyzed through 22 morphometric measurements and fineness ratio to identify morphological patterns related to swimming performance. Four species groups were indicated by the Cluster analysis: I) R. vulpinus; II) P. corruscans; III) L. macrocephalus, L. elongatus, P. lineatus, P. maculatus, and S. brasiliensis - measurements of head height and anal fin length formed this group; and IV) P. granulosus and P. pirinampu - measurements of maximum body width and caudal peduncle width contributed to form this group. The morphometric variables that most contributed to the distinction were head length and mouth width for groups I and II. The species R. vulpinus and P. granulosus differed from other species, showing fineness ratios of 9.4 and 3.7, respectively. Leporinus elongatus, L. macrocephalus, P. lineatus, P. maculatus, and S. brasiliensis showed significant differences from other species, with ratios ranging from 4.57 to 5.19, indicating that these species may be better swimmers. Long-distance migratory species using the Piracema Canal to ascend upstream areas differed morphologically, morphological characteristics such as a narrow caudal peduncle and maximum body length, besides to the values of the fineness ratio, were essential to differentiate the migratory species.

Polymorphism of <I>MSTN</I> gene and its association with growth traits in yellow catfish (<I>Pelteobagruse fulvidraco</I>)

Myostatin (MSTN) gene has negative influence on the growth of muscle, which belongs to transforming growth factor-β family. Using single-strand conformation polymorphism (SSCP), single nucleotide polymorphisms (SNPs) of MSTN gene were detected in yellow catfish. Correlation analysis between MSTN polymorphisms and growth traits was also carried out. Results indicated that five genotypes (AA, BB, CC, CD and DD) were found in the first intron with one deletion site and two mutant sites (T1003del, G1022A and T1063G), two genotypes (EE and EF) were found in the third exon with one mutant site (T132C). The individuals with genotypes AA had a lager value than the individuals with the genotype CD and DD in total length, body length, body height, body width, head length and body weight (Plt;0.05). The female individuals with genotypes AA also had a lager value than the female individuals with genotypes DD in total length, body length, body height, body width, caudal peduncle height, caudal peduncle width and body weight (Plt;0.05). This implies that genotype AA has a positive influence on the growth traits of female yellow catfish, and genotype DD is opposite. Genotypes AA and DD can be used in marker assisted selection of female yellow catfish breeding in the future.

Comparative development of five sympatric coastal Fundulid species from the northern Gulf of Mexicoa

There are five coastal fundulid species in the northern Gulf of Mexico (nGOM) including Fundulus jenkinsi, which is recognized within all states from Louisiana through Florida and federally as a Species of Concern. This particular fundulid was listed because of a perceived linkage to salt marsh habitat, only scant data available on its ecology, and salt marsh habitat being altered throughout its range. Little is known about the life history of this coastal killifish, but a detailed diagnostic key of the early life stages of select members of Fundulidae can provide the foundation needed to accurately identify this rare species in need of conservation. Larval and postlarval stages of select members of the family Fundulidae along the east coast of the U.S. have been described and compared among species. We illustrated various stages of coastal Fundulus spp. and Adinia xenica in the northern GOM and quantified morphometric and meristic characters. Total length, head length, body depth, caudal peduncle width, snout length, eye diameter, anal and dorsal fin counts, and diagnostic pigment patterns were compared among species. The first branch of our dichotomous key utilized the number of branchiostegal rays to separate young fundulids (< 15 mm TL) into two groups that can then be identified by selected pigment patterns, morphometrics, and meristics.

Morphometric differences among populations of Tu’ini, Capoeta damascina (Teleostei: Cyprinidae), in the interior basins of Iran

Summary Tu’ini, Capoeta damascina, is a widespread species in the interior basins of Iran. To examine the morphometric variations residing within the taxon, six isolated river systems from the west, south, southwest, and centre of Iran were investigated: Gharasu, Hanna, Bazoft, Eghlid, Abadeh, and Gamasiyab. A total of 240 adult fish specimens ≥180 mm standard length (females: 180–336; males: 186–304) were collected from March to June 2008. Based on the multivariate methods used (factor analysis, canonical variates analysis, and a classificatory discriminant analysis), the river samples were clearly separated into distinct groups. The Gharasu River sample was separated into a distinct group by differences in inter-nasal distance (iND), inter-orbital distance (iOD), and barbel length; the Hanna by iND, iOD, body depth (BD), minimum BD, caudal peduncle (CP) depth, CP width, and pectoral-anal distance; the Bazoft by head depth, iND, CP length, and preanal length; the Eghlid by anal-caudal distance; the Abadeh by postorbital length; and the Gamasiyab River by preorbital length, dorsal fin height and base, eye diameter, BD, preventral length, and pectoral-ventral distance.

Ecomorphology and habitat utilization of Cottus species

We investigated relationships between morphological attributes and mesohabitat use in populations of Cottus carolinae. Field studies revealed significant differences between Ozark and prairie stream mesohabitats where populations of C. carolinae occurred. Features of the mesohabitat that were characteristic of each stream type correlated with intra- and inter-specific differences in morphological attributes of Cottus. The morphology of Cottus occurring in the deeper, slower, and siltier prairie stream exhibited larger head width and depth, body width and depth, and caudal peduncle width while those occurring in a shallower, faster flowing Ozark stream had longer pelvic fins, larger eyes, and deeper caudal peduncles. Each population had a morphology tailored to optimize its performance in a specific habitat. Results of laboratory based performance studies using a variable flow chamber revealed that critical current velocities (CCV) of live and preserved specimens were weakly associated with distinct combinations of morphological traits. Specimens with higher CCV measurements typically had longer pelvic fins, larger eyes, and deeper caudal fins (Ozark morphology). Those with lower CCVs had larger head width and depth, body width and depth, and caudal peduncle width (prairie morphology) in studies using cobble as the substrate. Differences in flow regimes between prairie and Ozark streams may generate specific niches for specific morphotypes, and current velocity may exert selective pressure on morphology.

Comparative morphology and diet of young cichlids in the dammed Sinnamary river, French Guiana, South America

The growth of most mensural characters of Krobia guianensis and Crenicichla saxatilis during early development was explained by a split regression indicating inflection in allometry at specific standard lengths. Double‐centred PCA revealed morphological transformations during ontogeny mostly under the influence of the maximum body depth and the maximum caudal peduncle width, the area of the caudal fin and the horizontal diameter of the eye contributing also, but to a lesser extent. Young K. guianensis switched to larger prey at the end of the period when the growth of most of their studied mensural characters demonstrated an inflection, but young C. saxatilis changed their diet at a much smaller size than that at which an inflection occurred. However, in the lower reservoir sites, most young juveniles of K. guianensis and C. saxatilis did not switch to larger items during their ontogeny and micro‐crustaceans occurred more frequently in their diet. It is hypothesized that the low net energy gained when eating such small prey may explain why the young of both species were thinner at these sites than in their undisturbed habitats. If food resources of young cichlids do not improve in the Petit‐Saut reservoir, it is hypothesized that these species will develop stunted populations there.

Population-specific variation in body dimensions of adult chinook salmon (Oncorhynchus tshawytscha) from New Zealand and their source population, 90 years after introduction

Chinook salmon (Oncorhynchus tshawytscha) transplanted from the Sacramento River, California, U.S.A., to New Zealand in the 1900s colonized many South Island rivers, which now show significant population-specific phenotypic variation. To characterize this variation, we conducted a morphometric analysis of two New Zealand populations and the fall-run Battle Creek population at the Coleman Hatchery, the apparent ancestral stock. Variation in length at age, weight at length, fin lengths, hump depth, snout length, and caudal peduncle width was detected among populations. Sexually mature Battle Creek and New Zealand chinook salmon were consistently identifiable from morphometric data (97.7% classification accuracy), largely through differences in caudal peduncle width and hump depth. The two New Zealand spawning populations, although distinguishable in morphology in 1994 (mean of 80% correct classification), did not classify as well using the same discriminant functions in 1995 (mean of 62.7% correct), suggesting interannual multivariate effects. Little variation was observed between the two mainstem river populations in adults collected shortly after entering freshwater. Although the genetic or environmental causes for the differences between populations have yet to be determined, our results provide empirical evidence of phenotypic divergence over decadal time scales. This work may be relevant to considerations in the development and monitoring of salmon recovery and conservation programs.

An anomalous specimen of Rhamdia guatemalensis (Günther, 1864)

In March of 1984 an immature Rhamida guatemalensis(Günther, 1864) lacking the right pectoral fin (Fig. 1) was captured in the Sangregado sector, Arenal Dam, Guanacaste, Costa Rica (10°28′ N, 84°46′W) The body colouration and morphometric characteristics were as described for this species (Bussing 1966; Zúñga, 1980). X‐ray examination revealed the absence of the radial bones and the fin rays of the right peoctoral fin. External examination of the tegument of this region showed no scars or evidence of accidental loss of the appendage, indicating that the fin had never developed.Morphometric data from this abnormal specimen are: total length, 14.25 cm, standard length, 11.98cm; maximum height of body, 22.35 cm; maximum width of body, 2.40 cm, caudal peduncle width, 1.27 cm; head length, 3.00cm.

CORRELATIONS AMONG MOFPHOMETRIC TRAITS OF FINGERLING CATFISHES AND THE RELATIONSHIP TO DRESSING PERCENTAGE AT HARVEST

ABSTRACTBlue (Ictalurus furcatus), channel (I. punctatus), white (I. catus) and hybrid catfish grown under similar conditions to a size of 30 g differed in their body conformation (head length, head width, head depth, body depth, caudal peduncle depth and caudal peduncle width to total length ratios; P <.01) and dressing percentage (P < .05). Strains of channel catfish also differed from each other in their body conformation (P < .01) and dressing percentage (P < .05). Body conformation at 30 g was correlated to dressing percentage at 500 g (P < .01). Head width, caudal width and body depth had the largest effects upon dressing percentage (P < .05). Blue catfish, Auburn and Rio Grande strains of channel catfish had higher dressing percentage (P < .05) than the hybrids, white catfish and four remaining channel catfish crosses. Auburn x Rio Grande channel catfish crossbreds had larger (P < .01) heads, caudal peduncles and body depth than their parents, but the Marion x Kansas crossbred channel catfish did not have larger values than their parents. It appears that overdominance for body conformation was prevalent in intraspecific crossbreds. Morphologies of channel‐blue hybrids were between those of their parent species. The correlations between morphometric traits were different (P < .01) among the 10 genetic groups.

Deep-Water Ninespine Sticklebacks, Pungitius pungitius, in the Mississippi Drainage, Crooked Lake, Indiana

A population of Pungitius pungitius was found in 1966 in Crooked Lake, Noble-Whitley counties, Indiana, the southernmost locality for the species in inland North America. This is the first population to be described indigenous to the Mississippi drainage, one of the postulated refugia for the species during Wisconsin glaciation. Morphological comparisons with populations thought to have been derived from a Mississippi refugium agreed in most respects, but Crooked Lake and Lake Michigan populations differed in pelvic girdle shape and caudal peduncle width. The full number of dorsal spines and caudal scutes were first present at 13 and 21 mm standard length, respectively, in Crooked Lake Pungitius. The pelvic spine first appeared at 14 mm. Pungitius was found between five and 30 m by collecting with rotenone, monofilament gillnets, and Plexiglas traps. Young specimens were most common just within, and a few meters below, the rooted aquatic zone while the adults occurred in greatest numbers in deeper water. Fully ripe females were found from 9 June to 22 July in 1966 and from 9 April to 24 August in 1967. The temperature ranged from 50 to 250 C at the stratum where Pungitius lived in the summer. Most adults were caught in 6?-120 C water, but were able to survive one week in live boxes at surface shore temperatures of 24?-28? C.