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The aim of this study was to investigate body shape variations of Alosa braschnikowi populations in three localities of the Caspian Sea using geometric morphometric method. So that, 216 specimens were caught from three regions from west to east, including Guilan (Anzali), Mazandaran (Sari) and Golestan (Miankaleh). Shape data was extracted using 15 landmark points on 2-D pictures of specimens. The PCA, DFA analyses and cluster analysis based on Euclidean square distances were used to examine shape differences among the three populations. The results showed that there was a significant difference between the studied populations in terms of body shape (p

Morphological studies are strong and instrumental for determining discreteness of the similar species and extensively used to identify differences between fish populations. A total of 216 specimens of Alosa braschnikowi were randomly collected by beach seine from three fishing regions along the southern Caspian Sea coasts, including some regions of Miankaleh, Sari and Anzali, in the fishing season during 2018-2019. The extracted landmark-points (body shape data) were submitted to a generalized Procrustes analysis (GPA) to remove nonshape data in PAST software. In the present study, the size effect was removed successfully by procrustes action in PAST software. Principal component analysis (PCA) was performed to summarize the variation among the specimens as few dimensions as possible. As a complement to discriminant analysis, morphometric distances among the three localities were inferred to cluster analysis by adopting the Euclidean square distance as a measure of dissimilarity method as the clustering algorithm. The dendrogram derived from cluster analysis of Euclidean square distances showed that the three populations of A. braschnikowi were distinct from each other in terms of morphometric characters. The Wilks' lambda tests of discriminant analysis indicated significant differences in morphometric characters of the three populations. The results of the present study demonstrated significant morphological differences between the three populations of A. braschnikowi. These differences in the three studied basins were mainly related to the characteristics of head and snout, body height, caudal peduncle, dorsal and anal fin base, which could be related to the hydraulic conditions and diet of the populations. [ABSTRACT FROM AUTHOR]

Genetic diversity studies are essential in characterization of populations and species conservation. Alosa braschnikowi is a commercially valuable species native to the Caspian Sea. It is thought to have eight to nine subspecies, but the genetics of these populations remains to be investigated. The present study was performed to evaluate the genetic population structures of Caspian marine shad (Alosa braschnikowi) in the southern coast of the Caspian Sea using six pairs of SSR markers. A total of Alosa braschnikowi 140 specimens through five locations across the southern coast of the Caspian Sea were genotyped and 130 alleles were identified. The overall mean values of Ho and He were 0.58 and 0.87, respectively, with the highest and minimum value of Ho observed in Sari (0.67 ± 0.08) and Miankaleh (0.50 ± 0.04), respectively. The overall mean value of allelic richness was 12.6. The data suggest that there was a high rate of migration between populations of Alosa braschnikowi (overall mean of Nm = 13.57), with the highest value (19.07) between Gomishan and Mahmodabad locations. AMOVA results showed that 96% of variation was related to within populations and only 4% belonged to between populations. The mean Fst value of 0.019 indicates a low level of population differentiation. Our data suggest that there may be two genetically separate populations of Alosa braschnikowi across the southern coast of the Caspian Sea and a high rate of migration is likely to limit genetic diversity between them.

Genetic diversity studies are essential in characterization of populations and species conservation. Alosa braschnikowi is a commercially valuable species native to the Caspian Sea. It is thought to have eight to nine subspecies, but the genetics of these populations remains to be investigated. The present study was performed to evaluate the genetic population structures of Caspian marine shad (Alosa braschnikowi) in the southern coast of the Caspian Sea using six pairs of SSR markers. A total of Alosa braschnikowi 140 specimens through five locations across the southern coast of the Caspian Sea were genotyped and 130 alleles were identified. The overall mean values of Ho and He were 0.58 and 0.87, respectively, with the highest and minimum value of Ho observed in Sari (0.67 ± 0.08) and Miankaleh (0.50 ± 0.04), respectively. The overall mean value of allelic richness was 12.6. The data suggest that there was a high rate of migration between populations of Alosa braschnikowi (overall mean of Nm = 13.57), with the highest value (19.07) between Gomishan and Mahmodabad locations. AMOVA results showed that 96% of variation was related to within populations and only 4% belonged to between populations. The mean Fst value of 0.019 indicates a low level of population differentiation. Our data suggest that there may be two genetically separate populations of Alosa braschnikowi across the southern coast of the Caspian Sea and a high rate of migration is likely to limit genetic diversity between them. [ABSTRACT FROM AUTHOR]

The present study was carried out to determine population structure of Alosa braschnikowi, one of the endemic species in the Caspian Sea, with five polymorphic microsatellite loci (AsaD030, AsaD042, AsaC249, AsaD312, AsaC051). Fifty six specimens of A. braschnikowi were collected from Gomishan and Miankaleh (28 specimens for each population) in Golestan province. The results showed that the average observed heterozygosity for Gomishan and Miankaleh were 0.536 and 0.514, respectively, with an average of 0.525 for the two populations. The number of observed alleles per locus ranged from 8 to 17 with an average of 12.4 alleles. Average number of effective allele in Gomishan and Miankaleh was calculated 8.53 and 7.61. Also, in eight cases of 10 tests in Hardy-Weinberg equilibrium there was statistically significant deviation (P

The present study was carried out to determine population structure of Alosa braschnikowi, one of the endemic species in the Caspian Sea, with five polymorphic microsatellite loci (AsaD030, AsaD042, AsaC249, AsaD312, AsaC051). Fifty six specimens of A. braschnikowi were collected from Gomishan and Miankaleh (28 specimens for each population) in Golestan province. The results showed that the average observed heterozygosity for Gomishan and Miankaleh were 0.536 and 0.514, respectively, with an average of 0.525 for the two populations. The number of observed alleles per locus ranged from 8 to 17 with an average of 12.4 alleles. Average number of effective allele in Gomishan and Miankaleh was calculated 8.53 and 7.61. Also, in eight cases of 10 tests in Hardy-Weinberg equilibrium there was statistically significant deviation (P<0.001). The average amount of gene flow and Fis were 17.34 and 0.395, respectively. The Fst value was 0.016 which was indicative of the low genetic differentiation between the Gomishan and Miankaleh populations that could be due to the natural migration of the fishs. The results for molecular variance analysis based on Fst index, exhibited that genetic diversity within population was only 1 percent and among populations was 99 percent. The results of present study showed that although the genetic diversity of A. braschnikowi in Golestan province was appropriate, it is possible that genetic bottleneck will arise in future years. [ABSTRACT FROM AUTHOR]

The feeding habits of Caspian marine shad, Alosa braschnikowi (Borodin, 1901) in Iranian waters of southern Caspian Sea were investigated by stomach content analysis of 357 fish collected monthly (October 2003 to April 2004) in the commercial catch. The diet consisted mainly of fish dominated by Atherinidae (58%), with Atherina boyeri being the dominant prey item based on numerical percentage. The next major food group was Gobiidae (26%), followed by Clupeidae (11%), Cyprinidae (3%), and Mugilidae (1%). Based on frequency of occurrence, A. boyeri was the main prey in the stomach of Caspian marine shad (Fi = 57.7%), with an important species index (ISI) of 59.7%. The fish fed on a wider variety of food items during November, December and February than during other months. The lowest feeding activity was recorded in October and January. The gastrosomatic index (GaSI) ranged from 0.3% to 27.7% with monthly variations increase in February and March coincides closely with spawning season and energy preservation for gonadal development. [ABSTRACT FROM AUTHOR]