Canonical Variables Research Articles

Interrelation between Nitrogen Doses and the Efficiency of Bt Genes in the Effective Control of Spodoptera frugiperda

The objective of this work was to identify the effect of nitrogen rates on Bt transgenic resistance and damage caused by Spodoptera frugiperda in corn plants at different developmental stages. The experimental design was a randomized complete block in a 3x6 factorial arrangement, with three potassium rates (0, 80, and 160 kg ha-1 kg of N) and six corn hybrids (20A55Hx, 30A77PW, AG1051, MG652PW, NS90VTPro2, and NS92VTPro), with three replicates. The data were analyzed through the analysis of canonical variables. Nitrogen doses interfere directly with the tolerance and resistance conferred by the Cry proteins of the plants in corn hybrids, altering the control of the caterpillar Spodoptera frugiperda and possibly favoring the breakdown of resistance in low availability. The corn hybrids showed divergent performance regarding proteins under low nitrogen availability (0 and 80 kg ha-1), and it was impossible to state which would be the most efficient protein. However, pyramiding has greater control under the recommended dose (160 kg ha-1 of N), with damage in the opposite direction to the transgenics.

A fault detection method based on sparse dynamic canonical correlation analysis

AbstractFault detection based on canonical correlation analysis (CCA) has received increased attention due to its efficiency in exploring the relationship between input and output. However, traditional CCA may generate redundant features in both the input and output projections while maximizing the correlations. In this paper, sparse dynamic canonical correlation analysis (SDCCA) is developed for dealing with the fault detection of dynamic processes. Through posing sparsity in the extraction of features, the interpretability of canonical variates is enhanced attributed to the sparsity of canonical weights. Based on the SDCCA model, the monitoring metric is established for fault detection. Moreover, the upper control limit (UCL) based on monitoring metrics is determined by the kernel density estimation (KDE) method to avoid the violation of the Gaussian assumption. The superiority of the proposed SDCCA‐based fault detection method is illustrated through a comparative study of the Tennessee Eastman process benchmark.

Optimization of Solar-Sail Control When a Vehicle Moves along Cyclic Heliocentric Trajectories

This paper considers the problem of constructing time-optimal trajectories for a spacecraft (SC) with a solar sail. The trajectories under consideration consist of repeated cycles of spacecraft movement to the target heliocentric orbit and back to the initial one. A model of a perfectly reflecting sail is used, which allows using the programs for optimal control of the sail angle, obtained on the basis of the Pontryagin maximum principle. The heliocentric motion is modeled in a flat polar coordinate system, and the spacecraft itself makes cyclic flights between two terrestrial planets along a closed trajectory. A boundary-value problem is formulated, in the solution of which the approach of the spacecraft to the target planet with the equalization of velocities is ensured (the encounter problem). Simulations of four cycles of Earth–Mercury–Earth and Earth–Mars–Earth motion with a characteristic acceleration of the solar sail of 0.25 mm/s2 have been carried out, for which the duration of one cycle is on average 2000 and 2341 days, respectively. Optimal sail-orientation control programs are obtained for a wide range of launch dates, and methods of searching for and choosing the initial values of conjugate variables are shown. The obtained results demonstrate the ability of a spacecraft with a solar sail to implement controlled motion along closed trajectories with a minimum duration of individual Earth–destination planet–Earth flights.

A multiple time scale approach for anisotropic inertial wave turbulence

Wave turbulence is the study of the long-time statistical behaviour of equations describing a set of weakly nonlinear interacting waves. Such a theory, which has a natural asymptotic closure, allows us to probe the nature of turbulence more deeply than the exact Kolmogorov laws by rigorously proving the direction of the cascade and the existence of an inertial range, predicting stationary spectra for conserved quantities, or evaluating the Kolmogorov constant. An emblematic example is given by fast rotating fluids for which a wave turbulence theory has been derived by Galtier (Phys. Rev. E, vol. 68, issue 1, 2003, p. 015301). This work involves non-trivial analytical developments for a problem that is anisotropic by nature. We propose here a new path for the derivation of the kinetic equation by using the anisotropy at the beginning of the analysis. We show that the helicity basis is not necessary to obtain the wave amplitude equation for the canonical variables that involve a combination of poloidal and toroidal fields. The multiple time scale method adapted to this anisotropic problem is then used to derive the kinetic equation that is the same as the original work when anisotropy is eventually taken into account. This result proves the commutativity between asymptotic closure and anisotropy. In addition, the multiple time scale method informs us that the kinetic equation can be derived without imposing restrictions on the probability distribution of the wave amplitude such as quasi-Gaussianity, or on the phase such as random phase approximation that naturally occurs dynamically.

Evaluation of age variation changes in cervical vertebrae: 2-Dimensional (2D) geometric morphometrics approach

Age estimation in adults is a complicated task because of various external factors occur concurrently with increasing age. The geometric morphometric method (GMM) is an approach that focuses on shape analysis and is widely recognized for its high reliability and reproducibility. The aim of this study was to explore the variation of cervical vertebrae among different age groups of the Malaysian population by GMM. Lateral skull radiographs of 432 subjects comprising four adult age groups; young adult age group (20–30 years old), early middle age group (31–40 years old), late middle age group (41–50 years old) and, elder adult age group (51–60 years old) were selected. Fifty-three 2-dimensional (2D) landmarks were applied to the digitalized radiographs by TPSDig2 (Version 2.31) software. Geometric morphometric analysis was performed by MorphoJ software. Results showed that the first three principal components (PC) contributed to 47.71 % of the cervical vertebrae variation and were shown in both lollipop and wireframe graphs. Procrustes ANOVA indicated that the shape was significantly different among different age groups. Canonical variate analysis revealed significant differences of both mahalanobis and procrustes distances among age groups with substantial individual overlap within groups. Discriminant function analysis (DFA) showed a correct classification rate for 61.5 % of cases respective to age groups. In conclusion, this study found significant differences in the shape of cervical vertebrae among different age groups of the Malaysian population using the GMM.

Molecular and morphometric study of Brazilian populations of Psychodopygus davisi.

In this study, we analysed the molecular and morphometric differences of several populations of the putative sand fly vector Psychodopygus davisi (Root, 1934) (Diptera, Psychodidae, Phlebotominae) in Brazil. We amplified the 658 base pair fragments of the DNA barcoding region-cytochrome c oxidase subunit 1 (COI) gene-for 57 specimens of P. davisi and three specimens of Psychodopygus claustrei (Abonnenc, Léger & Fauran, 1979). We merged our data with public sequences of the same species available from GenBank. Then, the combined dataset-87 sequences and 20 localities-was analysed using population structure analysis and different species delimitation approaches. Geometric morphometry of wings was performed for 155 specimens of P. davisi populations from the North, Midwest and Southeast Brazilian regions, analysing the differences in centroid sizes and canonical variates. Molecular analysis indicated high intraspecific genetic distance values for P. davisi (maximum p distance = 5.52%). All algorithms identified P. davisi and P. claustrei as distinct molecular taxonomic units, despite the low interspecific distance (p distance to the nearest neighbour = 4.79%). P. davisi sequences were split into four genetic clusters by population structure analysis and at least five genetic lineages using intermediate scenarios of the species delimitation algorithms. The species validation analysis of BPP strongly supported the five-species model in our dataset. We found high genetic diversity in this taxon, which is in agreement with its wide geographic distribution in Brazil. Furthermore, the wing analysis showed that specimens from the Southeast Region of Brazil are different from those in the North and the Midwest. The evolutionary patterns of P. davisi populations in Brazil suggest the presence of candidate species, which need to be validated in future studies using a more comprehensive approach with both genomic data and morphological characters.

Three-dimensional changes in the cranial base associated with soft-diet feeding.

Masticatory activity affects the morphology of the maxillo-mandibular complex, however, its influence on the cranial base remains to be elucidated. The recent integration of quantitative morphometric analysis with 3D imaging enabled a comprehensive and high-resolution morphological characterization of the craniofacial complex. We aimed to investigate the influence of masticatory activity on the morphology of the growing cranial base by three-dimensional (3D) geometric morphometric approach using micro-CT. The micro-CT data was reanalyzed to illustrate the 3D shape of the cranial base, and wireframe models were generated by connecting landmarks on the images. In the original study, mice were fed a soft diet (SD) of powdered pellets or a conventional hard diet (HD) for 6 weeks from 3 to 9 weeks of age, immediately after weaning. A principal component (PC) analysis analyzed shape variations and assessed their significance, while canonical variate (CV) analysis facilitated the comparison and differentiation of groups based on shape, unveiling meaningful shape distinctions. Three PCs were extracted that significantly separated the SD and HD groups among those explaining variations in shape. These PCs were related to the length of the sphenoid bone, the width of the anterior part of the sphenoid bone, and the length of the cranial base. Furthermore, one CV effectively distinguished SD from HD, and CV analysis showed that the sphenoid was shortened in the length and narrowed at the border of the temporal bone in SD mice. Masticatory loading affects the skeletal development of the cranial base. The morphology of the sphenoid bone was affected in both the sagittal and transverse axes.

Paleoenvironmental inferences on the Late Miocene hominoid-bearing site of Can Llobateres (NE Iberian Peninsula): An ecometric approach based on functional dental traits

Hispanopithecus laietanus from the Late Miocene (9.8 Ma) of Can Llobateres 1 (CLL1; Vallès-Penedès Basin, NE Iberian Peninsula) represents one of the latest occurrences of fossil apes in Western mainland Europe, where they are last recorded at ∼9.5 Ma. The paleoenvironment of CLL1 is thus relevant for understanding the extinction of European hominoids. To refine paleoenvironmental inferences for CLL1, we apply ecometric models based on functional crown type (FCT) variables—a scoring scheme devised to capture macroscopic functional traits of occlusal shape and wear surfaces of herbivorous large mammal molars. Paleotemperature and paleoprecipitation estimates for CLL1 are provided based on published regional regression models linking average FCT of large herbivorous mammal communities to climatic conditions. A mapping to Whittaker's present-day biome classification is also attempted based on these estimates, as well as a case-based reasoning via canonical variate analysis of FCT variables from five relevant biomes. Estimates of mean annual temperature (25 °C) and mean annual precipitation (881 mm) classify CLL1 as a tropical seasonal forest/savanna, only in partial agreement with the canonical variate analysis results, which classify CLL1 as a tropical rainforest with a higher probability. The former biome agrees better with previous inferences derived from fossil plants and mammals, as well as preliminary isotopic data. The misclassification of CLL1 as a tropical forest is attributed to the mixture of forest-adapted taxa with others adapted to more open environments, given that faunal and plant composition indicates the presence of a dense wetland/riparian forest with more open woodlands nearby. The tested FCT ecometric approaches do not provide unambiguous biome classification for CLL1. Nevertheless, our results are consistent with those from other approaches, thus suggesting that FCT variables are potentially useful to investigate paleoenvironmental changes through time and space—including those that led to the extinction of European Miocene apes.

Genetic diversity for agronomic and bromatological traits in forage cactus

This work aimed to estimate the genetic diversity in accessions of Opuntia ficus-indica collected in 13 regions of the semiarid region of Bahia. A total of 65 accessions were evaluated in a randomized complete block design, with three replications, at the Rio Seco experimental station belonging to the State University of Feira de Santana, Amélia Rodrigues-BA. Characterization of the accessions was made through the evaluation of 17 descriptors, namely 11 agronomic and six bromatological. The average Euclidean distance was used to estimate the genetic diversity among accessions. The shortest distances were obtained for accessions from the same collection site while the largest were observed in accessions 54 and 62 (10.32 DE) and 63 and 3 (10.22 DE). The analysis of canonical variables indicated cladodes total number (CTN), plant width (PW), CL, plant height (PH), ether extract (EE), and dry weight (DW) for discard as they presented the lowest contribution of the data set variation. Principal component analysis and K-means method were used to establish the clusters, and the formation of four groups was indicated. The first two principal components captured 52.5% of the total variation present in accessions. The descriptors with the greatest contribution to the variation observed in O. ficus-indica were total cladode photosynthetic area (TCPA), cladode area (CA), and cladodes width (CW). There is divergence between cactus forage accessions collected in the semiarid region of Bahia. This information will allow the use of these materials for the formation of segregating populations in the genetic improvement program of the State University of Feira de Santana. The accessions of groups III and IV should be explored by the forage cactus breeding program, as they presented greater productive potential.

Taniatrechus xeniae sp. nov. (Coleoptera: Carabidae: Trechini), the second species of the most specialised troglobitic carabid genus of the Caucasus

Taniatrechus xeniae sp. nov., the second species of the genus, is described from Prostornaya Cave in the central part of the Bzyb Mountain Range, Abkhazia. A comparative study of all available specimens of the genus is carried out using both linear morphometrics (indices) and geometric morphometrics: generalised Procrustes analysis (GPA), principal component analysis (PCA), and canonical variate analysis (CVA). This study allowed us to estimate infraspecific variation in the external morphology of T. setosus Belousov et Dolzhansky, 1994, on the one hand, and to reveal reliable diagnostic features that distinguish between the two species, on the other. The diagnosis and description of the genus are completed to include the new species and variation found in the type species. Some characters were also described more accurately or corrected based on more abundant material. The major morphological features of Taniatrechus spp. are photographed, their geographic distribution is mapped, and new data on living conditions of the genus are provided. The members of the genus seem to be the most specialised hypogean Trechini in the Caucasus, with the deepest finding ever reported for Coleoptera (one specimen of T. setosus was found at a level of 1,800 m below the cave entrance). In view of recent discoveries in highlands, the subterranean layer suitable for living of hypogean insects may reach more than three km thick in intensively folded karst areas. Thus, the hypogean life is much more widespread than previously thought. Prostornaya Cave, the type locality of T. xeniae sp. nov., is described for the first time.

Morphometric Differentiation of the Swimming Crab Portunus sanguinolentus (Herbst, 1783) Populations in East Asia: Implications for Stock Identification and Management

Morphometric disparities were employed to characterize the geographical variations in and elucidate the phylogeography of Portunus sanguinolentus in East Asia. In this study, a comprehensive assessment was undertaken based on measurements from 833 individual crabs. These crabs were sampled from eight distinct locations, namely Kyushu (KS), Fuzhou (FZ), Yilan (YL), Xiamen (XM), Tainan (TN), Hong Kong (HK), Vietnam (VN), and Singapore (SG). Twelve morphometric measurements were standardized based on size using the allometric method. A cluster analysis and a canonical variate analysis (CVA) were then conducted for a data analysis. Randomization tests were subsequently performed to validate the morphometric differences observed among the groups. The analytical results classified the eight sampled populations into at least two distinct clusters. The first cluster included three samples from China (specifically FZ, XM, and HK), while the second cluster consisted of samples from East Asia (including KS, YL, TN, VN, and SG). The CVA revealed a tripartite division into three groups: the mainland China group (FZ, XM, and HK), the Kuroshio group (KS, YL, and TN), and the Southeast Asia group (VN and SG). The observed morphometric variations between these broad groups were statistically significant for both genders. These differences may be attributed to evolutionary origins, geographical events, or environmental adaptations. This study highlights the effectiveness of morphometric techniques in providing comprehensive insights into species delimitation and philogeographic relationships.

The association between quality of life and subjective wellbeing among older adults based on canonical correlation analysis.

The study explored the relationship between subjective well-being and the quality of life among older adults. It highlights the importance of understanding how these factors are interconnected in the context of an aging population. Descriptive statistics were used to analyze the scores of general demographic characteristics, subjective wellbeing and quality of life. Simple correlation analysis and canonical correlation analysis were employed to analyze the relationship between subjective wellbeing and quality of life among older adults. Data from 892 older adults were collected. Canonical correlation analysis revealed four pairs of canonical variables, with the first four pairs of canonical correlation coefficients all being statistically significant (0.695, 0.179, 0.147, 0.121) (p < 0.05), and the first pair of canonical variables explaining 93.03% of the information content. From the canonical loading coefficients, Vitality and mental health contributed the most to the quality of life (U1) canonical variable. The canonical variable V1, which corresponded to subjective wellbeing, was reflected by a combination of positive affect, negative affect, positive experience and negative experience. X1 (physical functioning), X2 (role-physical), X3 (bodily pain), X4 (general health), X5 (vitality), X6 (social functioning), X7 (role-emotional) and X8 (mental health) were positively correlated with Y1 (positive affect) and Y3 (positive experience), negatively correlated with Y2 (negative affect) and Y4 (negative experience). Cross-loadings revealed that physical functioning, bodily pain, general health, vitality, social functioning and mental health were the main factors reflecting the subjective wellbeing of older adults. As quality of life among older adults was highly correlated with subjective wellbeing, appropriate measures should be taken to account for individual characteristics of older adults, and various factors should be integrated to improve their subjective wellbeing.

Size and shape of human mandible: Sex differences and influence of age on sex estimation accuracy

The degree of sexual dimorphism expressed by human bones is of primary importance for the development of accurate methods for sex estimation. The objective of the present study was to investigate sex differences in shape and size of the mandible using geometric morphometric methods. The study also aimed to examine the impact of age on the sex classification ability of the size and shape of the mandible. Computed tomography images of 190 Bulgarians (98 males and 92 females) were used in the study. Polygonal surface models of the skulls were generated and used for digitizing 45 landmarks located on the mandible. The raw three-dimensional coordinates of the landmarks were processed via generalized Procrustes superimposition. The sex differences in mandibular size and shape were evaluated for statistical significance. Multivariate regression was applied for correction of the allometric effect. Principal component analysis, discriminant analysis, and canonical variate analysis were also used in the study. Mandibular size differed significantly between males and females and achieved a sex classification accuracy of 87%. The significance of the sex differences in mandibular shape depended on the type of shape variables used in the analysis. The shape variables provided different classification accuracy: 78% using the Procrustes coordinates and 53% using the regression residuals. The male and female mandibles differed significantly in size and shape, including the allometric component. Mandibular size is a more effective sex indicator than shape. Age has an ambiguous effect on the classification accuracy of the size and shape variables of the mandible.

A morphometric approach to morphology analysis of palatal rugae in sibling groups.

Recent advances in imaging technologies, such as intra-oral surface scanning, have rapidly generated large datasets of high-resolution three-dimensional (3D) sample reconstructions. These datasets contain a wealth of phenotypic information that can provide an understanding of morphological variation and evolution. The geometric morphometric method (GMM) with landmarks and the development of sliding and surface semilandmark techniques has greatly enhanced the quantification of shape. This study aimed to determine whether there are significant differences in 3D palatal rugae shape between siblings. Digital casts representing 25 pairs of full siblings from each group, male-male (MM), female-female (FF), and female-male (FM), were digitized and transferred to a GM system. The palatal rugae were determined, quantified, and visualized using GMM computational tools with MorphoJ software (University of Manchester). Principal component analysis (PCA) and canonical variates analysis (CVA) were employed to analyze palatal rugae shape variability and distinguish between sibling groups based on shape. Additionally, regression analysis examined the potential impact of shape on palatal rugae. The study revealed that the palatal rugae shape covered the first nine of the PCA by 71.3%. In addition, the size of the palatal rugae has a negligible impact on its shape. Whilst palatal rugae are known for their individuality, it is noteworthy that three palatal rugae (right first, right second, and left third) can differentiate sibling groups, which may be attributed to genetics. Therefore, it is suggested that palatal rugae morphology can serve as forensic identification for siblings.

A geometric morphometric analysis of variation in Australian frog ilia and taxonomic interpretations.

Anurans including frogs and toads exhibit an ilium that is often regarded as taxonomically diagnostic. The ilium, one of the three paired bones that make up the pelvic girdle, has been important in the fossil record for identifying anuran morphotypes. Osteological collections for Australian frogs are rare in herpetological museums, and skeletonizing whole-bodied specimens requires destroying soft tissue morphology which is valuable to anuran specialists working on living species. Computed tomography scans provide the opportunity to study anuran osteology without the loss of soft tissues. Our study, based on microcomputed tomography scans of extant Australian frogs from the public repository Morphosource and from museum collections focuses on the morphological differences between Australian frogs at the familial and generic levels using geometric morphometrics to compare the diagnostic shape of the ilium. Principal component analysis (PCA) and canonical variate analysis (CVA) were conducted to assess differences in the ilium between supraspecific groups of Australian frogs. The canonical variates analysis accurately predicted group membership (i.e., the correct family) with up to 76.2% success for cross-validated predictions and 100% of original group predictions. While the sample was limited to familial and generic level analyses, our research shows that ilial morphology in Australian frogs is taxonomically informative. This research provides a guide for identifying Australian anurans, including fossils, as well as new information relevant to considerations about their phylogenetic relationships, and the potential use of the fossil record to enhance efforts to conserve threatened living frog species.

Strengthening the atom-field coupling through the deep-strong regime via pseudo-Hermitian Hamiltonians

We present a strategy for strengthening the atom-field interaction through a pseudo-Hermitian Jaynes-Cummings Hamiltonian. Apart from the engineering of an effective non-Hermitian Hamiltonian, our strategy also relies on the accomplishment of short-time measurements on canonically conjugate variables. The resulting fast Rabi oscillations may be used for many quantum optics purposes and specially to shorten the processing time of quantum information.

Fifth-order nonlinear Schrödinger equation as Routhian reduction of the nonlinear Klein–Gordon model

We consider the nonlinear Klein–Gordon model with polynomial nonlinearity involving odd and even powers. We elaborate a hybrid Hamiltonian and Lagrangian approach, which is generally referred to as Routh’s procedure, to describe the nonlinear modulation of wave packets assuming the wave field envelope to be a slow function of time and coordinate. An extended fifth-order nonlinear Schrödinger equation is obtained from the Routhian equation for a complex canonical variable that couples the wave field and its momentum. This canonical variable is expressed in terms of the amplitude of fundamental harmonic and its derivatives with respect to coordinate. The resulting fifth-order nonlinear Schrödinger equation is demonstrated to be a Hamiltonian system under a certain constraint imposed on its model parameters. When compared with other techniques used to derive high-order nonlinear Schrödinger models, our approach preserves the Hamiltonian structure of the governing equations for the fundamental harmonic, while the input of higher harmonics is taken into account by means of variational principle applied to the averaged Routhian. In this way, it represents the most general tool for the reduction of nonlinear wave equations to high-order envelope models for slowly modulated wave packets.

Multiview Regularized Discriminant Canonical Correlation Analysis: Sequential Extraction of Relevant Features From Multiblock Data.

One of the important issues associated with real-life high-dimensional data analysis is how to extract significant and relevant features from multiview data. The multiset canonical correlation analysis (MCCA) is a well-known statistical method for multiview data integration. It finds a linear subspace that maximizes the correlations among different views. However, the existing methods to find the multiset canonical variables are computationally very expensive, which restricts the application of the MCCA in real-life big data analysis. The covariance matrix of each high-dimensional view may also suffer from the singularity problem due to the limited number of samples. Moreover, the MCCA-based existing feature extraction algorithms are, in general, unsupervised in nature. In this regard, a new supervised feature extraction algorithm is proposed, which integrates multimodal multidimensional data sets by solving maximal correlation problem of the MCCA. A new block matrix representation is introduced to reduce the computational complexity for computing the canonical variables of the MCCA. The analytical formulation enables efficient computation of the multiset canonical variables under supervised ridge regression optimization technique. It deals with the "curse of dimensionality" problem associated with high-dimensional data and facilitates the sequential generation of relevant features with significantly lower computational cost. The effectiveness of the proposed multiblock data integration algorithm, along with a comparison with other existing methods, is demonstrated on several benchmark and real-life cancer data.

Conjugate variables approach tomixedq-Araki–Woods algebras: Factoriality and non-injectivity

We establish factoriality and non-injectivity in full generality for the mixed q-Araki–Woods von Neumann algebra associated to a separable real Hilbert space HR with dimHR≥2, a strongly continuous one parameter group of orthogonal transformations on HR, a direct sum decomposition HR=⊕iHR(i), and a real symmetric matrix (qij) with supi,j|qij| &amp;lt; 1. This is achieved by first proving the existence of conjugate variables for a finite number of generators of the algebras (when dimHR&amp;lt;∞), following the lines of Miyagawa–Speicher and Kumar–Skalski–Wasilewski. The conjugate variables belong to the factors in question and satisfy certain Lipschitz conditions.

Variations in Otolith and Scale Shape of the Invasive Round Goby Neogobius melanostomus Populations from Different Habitats of the Sava River Basin, Croatia

Abstract Round goby Neogobius melanostomus is one of the three invasive Ponto-Caspian gobies found in the Sava River basin in Croatia. It has a negative effect on the native ecosystems due to its high invasive potential that enables its rapid spread upstream in inland watercourses. The objective of this study was to determine the differences in sagittal otolith and scale shape of the frontal and established populations of N. melanostomus in two different habitat types. At two sampling sites in the main course of the Sava (Babina Greda, Slavonski Brod) and in a modified habitat (Sava-Odra canal), 20 individuals of N. melanostomus were collected and analysed. The geometric morphometric method was used together with Procrustes analysis of variance, canonical variate analysis and discriminant function analysis to analyse the otolith and scale shape. Significant differences in both otolith and scale shapes were found between settled (Babina Greda) and frontal (Slavonski Brod) populations from the main course of the Sava River. The main differences were the wider anterior part of the scales and a more pronounced open indentation on the otolith of the Babina Greda population. The settled population in the Sava-Odra canal was significantly different in otolith shape from the Babina Greda population but not from the Slavonski Brod population, suggesting that the upstream migration consisted of individuals with specific phenotype and genotype. Otoliths generally expressed greater shape variability than scales and thus may be more useful for differentiating between closely related populations on a finer scale. The results of this study suggest that the shape of otoliths and scales can be used to distinguish between closely related populations of N. melanostomus from different habitats but more comprehensive studies are needed due to the small number of samples.