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Killifish (Aphanius sophiae) of the Cheshme-Ali of Damghan and Shour River of Eshteherd were studied and compared from morphological point of view. For morphometric studies, 34 Truss morphometric measurements and  10 traditional  measurements  were made for each individual. Nine meristic traits were counted. Multi-variate analysis of variance (MANOVA) revealed a significant different between variables (P=O.OOO). Sexes and populations were using multi-variate analysis techniques such as Principle  Component Analysis and Discriminate Function Analysis based on morphometric variables. These variables seem to be under the influence of environmental factors such  as  temperature, salinity and feed condition. However, no separation was achieved based on meristic traits.

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Lanternfish (Benthosema pterptum) is one of the most important fish species in the Oman Sea. We randomly sampled 300 myctophids from different depths in spring and winter 2009 in the Oman Sea using mid-water trawls. Male to female sex ratio was 0.36:0.64. The thin sections (60-80μm) of sagitta otoliths of the fish were prepared using polishing method. These sections showed that increment growth rings of lanternfish otolith are formed daily and the age condition is distinguishable on a daily basis. We found the life span of the species to be short (with a maximum of 349 micro-increments counted) and probably less than a year. The relationship between standard length (SL) and daily growth increment (D) was expressed as the linear equation: SL=0.87D+12.37 (R2=0.97). The relationship between lanternfish weight (W) and daily growth increment (D) was expressed as power equation: W=0.00003D1.754 (R2=0.95). Furthermore, morphometrical characteristics of otolith including otolith weight and length and daily growth increment relationships were expressed as linear equation (R2=0.96 and R2=0.83). The results showed that lanternfish growth rate were in the range 0.241mm/d-1 to 0.138mm/d-1 and decreased by body size and age in this range. *Corresponding author

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Morphometric comparison of sagitta otolith in 10 clupeid species of the Persian Gulf and Oman Sea including Anodontostoma chacunda, Dussumieria acuta, Dussumieria elopsoides, Ilisha megaloptera, Ilisha melastoma, Nematolosa nasus, Sardinella gibbosa, Sardinella longiceps, Sardinella sindensis and Tenualosa ilisha), was conducted during 2007-2008. We found no significant differences in morphology and morphometry of the left and right otoliths except for A. chacunda and N. nasus. For the latter species the left sagitta otoliths were used. Investigation of otolith morphometric characteristics (length, breadth, weight, perimeter, area, and number of scallops) was also conducted which showed perimeter and number of scallops were the most effective individual otolith characteristics for distinguishing between species. The study indicated that sagitta otoliths have particular morphometric characteristics which are useful in identification of these species. *Corresponding author

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High mortality of beluga prelarvae (Huso huso) occurs in hatcheries and this appears to be linked to various abnormalities. Hence, this study was conducted to compare the body shape of alive and dead beluga prelarvae (5DPH) and to find the patterns of deformities among losses using geometric morphometric method. This method was applied to extract shape data as landmark’s Cartesian coordinates. Specimens were photographed using digital camera and the landmarks put on two-dimensional images using tpsDig2. Landmark data after GPA (Generalized Procrustes Analysis) analyzed using PCA and DFA. Results showed significant differences between alive and dead prelarvae shapes. In addition, various pattern of deformities found in the operculum, yolk sac and caudal peduncle parts. Future studies are suggested on larvae and juvenile stage.

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Landmark based geometric morphometrics and comparison of meristic characters was used to understand potential differences between populations of Waspi in Mashkil and Mokran Basins. 97 specimens of Waspies were caught (64 from Mashkil River and 33 from Sarbaz River). 14 landmarks were digitized on pictures taken from left side of specimens and meristic characters were counted. Data were analyzed using PCA and DFA after procrustes superimposition and data standardization. There are some meaningful shape differences between populations (P<0.001). The body and caudal peduncle in Sarbaz fishes where higher than that of Mashkil fishes, but the peduncle in Mashkil River was longer than Sarbaz fishes. Considering to no meaningful differences between the two populations in meristic characteristics and Due to different conditions in the rivers (vegetation density, water depth, water flow and food availably), the observed differences in shape of fishes could be considered as phenotype plasticity to the conditions of the rivers.

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Sexual dimorphism is a phenomenon among some fish species such as the members of the genus Aphanius. Among species with sexual dimorphism, morphological analysis needs to be performed separately. Hence, this investigation was carried out to determine suitable sex of Aphanius dispar for morphological studies. A total 180 specimens (male and female) were collected from populations of Sarbaz, Mehran and Shour rivers. Digital picture of speciments were taken from their left sides and then 17 landmark points cover their body shape were determined and digitized using tpsDig2 software. The data after GPA, were analyzed using PCA, CVA and MANOVA. The results revealed that studied population can be differitiated based on their body shap but between male and female of the Shour and Mehran rivers did not found significant different ib their separate analysis. Sexual dimorphism in the head and trunk seems to be a general feature in A. dispar. Based on the results in A. dispar, males can be suggested as proper sex for morphometric studies.

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Allometric growth pattern is a phenomena during early development of fishes. This research was conducted to study the allometric growth patterns of a hybrid triploid sturgeon (Acipenser baeri♂ x Huso huso♀) during early developmental stage up to 50 day post hatching (dph). Morphometric parameters of this study obtained from 2D pictures of specimens using the software ImageJ and allometric growth pattern was calculated as a power function of total length using non-transformed data: Y=ax^b. The results revealed that during early development of the triploid sturgeon after hatching, head and tail regions have positive allometric growth pattern that can be as result of importance vital functions, including swimming, respiration and sensory systems during this period. The inflexion points of the most body parts have been occurred prior 25dph and afterward their growth patterns were isometric. Despite the genetic difference between the hybrid triploid sturgeon with its parents, the results showed that its allometric growth patterns have many similarities with them. This results, also, provide evidence that the phenotypic plasticity plays important role in regulation of the body shape during early development.
 

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This research was conducted to study the phenotypic plasticity of the body shape in Carassius gibelio inhabiting lentic and lotic water bodies using geometric morphometric technique. For this purpose, a total of 119 specimens were collected from Sefid River (n=30), Alagol Lake (n=37), Khoda-Afarin dam Lake (n=21) and Mashkil River (n=31). To extracting body shape data in geometric morphometric method, the left side of specimens were photographed and 15 defined landmark-points were digitized on 2D images using TpsDig2 software. Data after general procratus analysis was analyzed using PCA, CVA, MANOVA and cluster analysis. The results showed a significant differences in the body shape between studied populations (p<0.001). Based on the results, populations of the Alagol and Khoda-Afarin dam lakes had deeper body and smaller head, and those of Sefid River had deeper body, but similar to the Mashkil population had larger head. In addition, Alagol and Khoda-Afarin dam lakes populations were placed together in same clad and those of the Sefid and Mashkil rivers in another clade, indicating the separation of populations inhabiting lentic and lotic habitats. The results also showed that the body shape of C. gibelio changes based on type of type of habitat.

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Ghost crabs are the largest invertebrates on sandy beaches around the world. The one of type of ghost crabs is Ocypode rotundata which is distributed on sandy beaches of Persian Gulf and Oman Sea. The aim of this study was discrimination of O. rotundata population using 33 morphometric characteristics selected of carapace, walking legs, abdomen, major chela by principle component analysis (PCA) in software of R. For this purpose, samples were collected at low tide by excavating (20-150 cm) in four zones of south and south western of Qeshm Island (Sakoo naft, Souza, Salakh, Kani). According to results, there were differences between individuals of some population in terms of investigated morphometric characteristics. On the other hand, most of the population showed overlapping which could not be separated together completely. Among the obtained morphological index traits are third walking leg length, body height, abdomen length, first part of abdomen width, fifth part of abdomen width, chela and merus length which can be reason for variety between individuals.

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The evolution of fish populations and adaptation to habitat conditions cause morphological differences between them. This study was conducted to investigate morphological variations between Southern Nase, Chondrostoma regium, populations in the sub-basins of the Persian Gulf basin, including the three-border western sub-basins, Karkheh and Karun, using geometric morphometric techniques. For this purpose, samplings were performed from the rivers of Alvand by 18 specimens, 24 from Behesht-Abad, 18 from Beshar (sub-basin of Karun), 14 from Diverab, and 6 from Homeil during 2018-2020. To extract body shape data, the left side of specimens was photographed, and 15 landmark points were digitized on obtained 2D pictures using tpsDig2. The extracted data were analyzed using multivariate analysis, including canonical variates analysis (MANOVA/CVA) and cluster analysis after GPA superimposition. The results revealed a significant difference between the Southern Nase populations of the studied rivers based on the body shape (P<0.05). The main differences in the body shape between the studied populations were in the head shape and size, body depth, snout position, and pectoral fin base. The results indicate the high phenotypic plasticity of this species in diverse habitats.

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In order to investigate the population structure of the whitefin wolf herring (Chirocentrus nudus) by morphometric and meristic characters method in the waters of the north of the Persian Gulf, from the three regions of Abadan, Shif and Bandar Abbas, 20 individual from each station and A total 60 fish was collected by gill net and it was prepared and transferred to the laboratory in May 2019. 29 morphometric traits and 5 meristic traits were measured. The results of the one-way analysis of variance of 12 morphometric characteristics among the samples had a significant difference at the 5% level, which indicates the phenotypic diversity in the whitefin wolf herring of the three studied regions. The results of the discriminant function analysis (DFA) about the morphometric traits showed that the populations of the whitefin wolf herring in Abadan, Shif and Bandar Abbas regions were separated from each other by 91.7%. The results of principal component analysis (PCA) for morphometric traits showed that 9 factors with eigenvalues ​​greater than 1 were selected, which includes 84.56% of the variation of morphometric traits. Based on the Kruskal-Wallis test, among the 5 meristic traits measured, two traits including the number of spines and rays of the dorsal fin and the number of soft rays of the pectoral fin were found to be significantly different at the 5% level (p≤0.05). The distribution diagram based on the first and second components, the dendrogram of the morphometric traits showed that there are at least two different populations of the whitefin wolf herring species in the Persian Gulf.

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In this study, relative growth, sexual dimorphism, and morphometric maturity of Ocypode rotundata and Austruca iranica were investigated on western south and northern of Qeshm Island. The samples were collected in February 2021. Based on the carapace width, the males of O. rotundata (33.1 mm) and males of A. iranica (12.4 mm) had average carapace width more than female crabs (32.2 mm and 11.2 mm). The male and female of A. iranica and O. rotundata had significantly different between three (first part of abdomen width, fourth part of abdomen width, and sixth part of abdomen width) and four (abdomen length, first part of abdomen width, and fourth part of abdomen width, sixth part of abdomen width) traits, respectively (p< 0.05). The calculated values of CW₅₀ based on the morphometric maturity for O. rotundata males with three methods of common, Bootstrap and Bayesian were 33.02 mm, 32.82 mm, and 33.05 mm, respectively. This value was 29 mm for female crabs with three methods. Also, the morphometric maturity values for males and females of A. iranica were similar to the three performed methods. The values in the male and female were obtained 11.61 mm and 9.15 mm, respectively. Based on the results, the CW₅₀ value in the male crabs for both studied species was more than the female crabs.