Southern Caspian Sea Basin Research Articles

New Morphological and Molecular Data on the Southern Ninespine Stickleback, Pungitius platygaster (Gasterosteidae) from Southern Caspian Sea Basin

Being a group of popular model organisms in eco-evolutionary biology, genetic, and genomic research studies, the genus Pungitius with 12 species is the most species-rich genus in the stickleback family Gasterosteidae including the Caspian nine-spine stickleback, Pungitius platygaster (Kessler, 1859), the only known species from southern Caspian Sea basin. Here, the new data based on morphological and molecular characters of the mtDNA COI barcode region, and current distribution range of P. platygaster is presented. These data confirm the validity of P. platygaster among its congeners, being sister clade to P. hellenicus from Greece. Morphologically, it is distinguished from the other congeneric species by complete pelvic girdle, 8−11 dorsal spines, and presence of large lateral scutes. The Caspian nine-spine stickleback is found in several closely placed freshwater and brackish waterbodies in the southern Caspian Sea.

New Morphological and Molecular Data on the Southern Ninespine Stickleback, Pungitius platygaster (Gasterosteidae) from Southern Caspian Sea Basin

New Morphological and Molecular Data on the Southern Ninespine Stickleback, Pungitius platygaster (Gasterosteidae) from Southern Caspian Sea Basin

Comparison between graph theory connectivity indices and landscape connectivity metrics for modeling river water quality in the southern Caspian sea basin

The maintenance of connectivity is critical to the proper functioning of an ecosystem. The present study was conducted with the aim of comparing graph theory connectivity indices and landscape connectivity metrics for the purpose of modeling river water quality. To conduct this study, a forest layer was extracted from land cover map and 25 large watersheds were selected. River water quality was then assessed from the perspective of 8 landscape connectivity metrics and 12 graph theory indices. We developed predictive models using stepwise linear regression, power, exponential, and logarithmic models to locate the best model form for each water quality parameter (dependent variable) we examined. The results indicated that models developed using graph theory connectivity indices resulted in higher coefficients of determination (R2) than models developed using landscape metrics. Only 5 independent variables from a potential set of 13 were significant in explaining the variation in water quality parameters. Also, the models with the highest R2 attempted to explain variations in CO3 (0.818), water discharge (0.733), and Ca levels (0.702). Therefore, the results of this study showed that graph theory connectivity indices had more significant correlation with water quality parameters compared to landscape connectivity metrics. This work also indicates that there exist nonlinear relationships among connectivity indices and water quality parameters.

Ponticola hircaniaensis sp. nov., a new and critically endangered gobiid species (Teleostei: Gobiidae) from the southern Caspian Sea basin.

Ponticola hircaniaensis sp. nov. is described as a new gobiid species from the Kaboudval Stream, southern Caspian Sea basin. The new species is diagnosed among Caspian Sea basin Ponticola species by the following combination of characters: second dorsal-fin branched rays 1416, anal-fin branched rays 1012, scales in lateral series 5259; lower jaw slightly, if at all, prognathous; head and body yellowish brown showing a reticulate brown pattern on a yellow background, first dorsal fin with a marginal bright orangish-yellow band and a dark anterior spot, upper part of pectoral-fin base with a distinct dark brown stripe; length of third spine in first dorsal fin 13.418.3 % of standard length (SL), second dorsal-fin spine length 11.113.8 % SL, caudal peduncle length and depth 16.420.1 % and 11.112.8 % SL, respectively, head depth at nape 70.981.0 % of head length (HL), and at eye 52.566.0 % HL; sagittal otolith dorsal rim with a broad concavity in the middle, dorsal depression absent or indistinct, sulcus length/sulcus height and sulcus height/otolith height ratios 1.471.82 and 0.340.40, respectively. It is also characterised by a K2P nearest neighbour distance of 5% to P. kessleri in the mtDNA COI barcode region. Mitochondrial and nuclear DNA analyses suggested extensive hybridization between P. hircaniaensis sp. nov. and P. gorlap at Kaboudval, providing evidence for the first record of hybridization in the Ponto-Caspian gobiids. Based on narrow geographic range isolated above the Zarrin Gol Dam (< 2 km2), extensive hybridization with P. gorlap, and other threats, the new species should be considered Critically Endangered.

Length-weight relationship and condition factor of three endemic fish species, Ponticola bathybius, Neogobius caspius and N. pallasi (Perciformes: Gobiidae) from the Southern Caspian Sea basin, Iran

In this study, the length-weight relationships (LWRs) and condition factors were estimated for 445 specimens belonging to three gobiid species viz. Ponticola bathybius (Kessler, 1877), Neogobius caspius (Eichwald, 1831) and Neogobius pallasi (Berg, 1916) from the Southern Caspian Sea basin. Total length and total weight of the examined specimens ranged 4.9-28.3 cm and 0.64-263.4 g, respectively. The length-weight parameter b of the studied species found between 2.47 (N. caspius) and 3.45 (N. pallasi) with r2 ranging 0.831 to 0.988. LWR and K parameters are reported first time for N. pallasi from the Caspian Sea basin. The condition factor estimated was calculated from 0.94 (N. pallasi) to 0.98 (N. caspius) and 1.00 (P. bathybius). The basic biological information on the LWRs of these three gobies will be useful as baseline information for further biological research in the region.

Watershed hydrological modelling in data scarce regions; integrating ecohydrology and regionalization for the southern Caspian Sea basin, Iran

The aim of this study is to evaluate an alternative approach to indicate how hydrological processes behave in a given watershed, and to test whether this approach can replace traditional calibration, particularly under data deficient conditions. Therefore, a regional calibration method (RC) was adapted to characterize “parameter-based hydrologic processes” as a function of watershed ecologic attributes. The methodological process included (1) temporal phase, (2) correlation analysis and (3) spatial phase. The defined methodology was carried out on a 4160 km2 area containing 21 watersheds laying in the southern coastal line of the Caspian Sea, Iran. By implementing the RC, regional models were specified corresponding to each hydrological process defined in the Tank model. Testing the reliability of the transferring process of hydrological parameters was conducted using multi-level accuracy comparison (MAC) benefiting from descriptive statistics, scatter-plots and T-test.Both temporal and spatial phases have shown acceptable outputs backed by their ecologic significance, but as an alternative approach to traditional calibration, the standalone RC still needs development to achieve a more robust basis covering all the parameters of the hydrologic model. According to the post-processor MAC, the transferability of six out of twelve regional models (height of lower outlet at the first tank, intermediate flow, deep-percolation, infiltration, surface flow, height of outlet at the second tank) was accepted with respect to the given tests. As such, our method outperformed the number of transferable parameters by an outstanding regional model predicting the surface flow in comparison with similar studies.Although the RC could not achieve total perfection, nevertheless it could still help users by providing more information about the contribution of ecologic variables in the prediction of the hydrological processes of a certain watershed.

Utilizing classic evolutionary algorithms to assess the Brown trout (Salmo trutta) habitats by ANFIS-based physical habitat model

Present study evaluates the application of coupled evolutionary algorithm- adaptive neuro-fuzzy inference system in the Brown trout riverrine habitats. We implemented the proposed method in the Lar national park as one of the most important Brown trout habitats in the southern Caspian Sea basin. Two classic evolutionary algorithms including the genetic algorithm and the particle swarm optimization were coupled with adaptive neuro-fuzzy inference system. Moreover, two conventional training methods including backpropagation and hybrid algorithm were utilized. Evaluation of developed models was carried out in two stages including assessment of habitat suitability index in observed habitats and using practical hydraulic simulation in a representative reach. Measurement indices consisting of root mean square error, mean absolute error, Nash–Sutcliffe model efficiency coefficient, reliability and vulnerability indices and fuzzy technique of order preference similarity to the ideal solution as decision-making system were used. Results demonstrate the efficiency of the coupled evolutionary algorithm- adaptive neuro-fuzzy inference system to simulate hydraulic habitats of the Brown trout. The first stage of evaluation indicates particle swarm optimization is the best method. However, practical hydraulic simulation corroborates GA is the best method for the training process. Evaluations demonstrate that backpropagation is not an appropriate method for ANFIS-based hydraulic habitat simulation.

Efficiency of coupled invasive weed optimization-adaptive neuro fuzzy inference system method to assess physical habitats in streams

This study presents a coupled invasive weed optimization-adaptive neuro fuzzy inference system method to simulate physical habitat in streams. We implement proposed method in Lar national park in Iran as one of the habitats of Brown trout in southern Caspian Sea basin. Five indices consisting of root mean square error (RMSE), mean absolute error (MAE), reliability index, vulnerability index and Nash–Sutcliffe model efficiency coefficient (NSE) are utilized to compare observed fish habitats and simulated fish habitats. Based on results, measurement indices demonstrate model is robust to assess physical habitats in rivers. RMSE and MAE are 0.09 and 0.08 respectively. Besides, NSE is 0.78 that indicates robustness of model. Moreover, it is necessary to apply developed habitat model in a practical habitat simulation. We utilize two-dimensional hydraulic model in steady state to simulate depth and velocity distribution. Based on qualitative comparison between results of model and observation, coupled invasive weed optimization-adaptive neuro fuzzy inference system method is robust and reliable to simulate physical habitats. We recommend utilizing proposed model for physical habitat simulation in streams for future studies.

Research Article: New report for Pristinella jenkinae Stephenson, 1931 (Annelida: Oligochaeta: Naididae) geographical distribution from Southern Caspian Sea basin, Mazandaran province -Iran

Pristinella jenkinae(Stephenson, 1931) is a freshwater cosmopolitan oligochaete. This species was found during limnological investigation in two rivers alongside Iranian coasts and has not been previously reported from Iran’s freshwater fauna and Southern Caspian Sea basin. The specimens of P. jenkinaewere collected bimonthly from Cheshmehkileh and Sardabrood rivers and estuaries (river mouth) using a Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) samplers at three stations in each estuary (S1: riverine, S2: estuary and S3: marine ecosystem) with three replicates from November 2014 through September 2015. Results of temporal distribution showed that the highest and lowest density and biomass of this species were in January (102.3±68.3 ind m-2 and 0.075±0.034g m-2) and in September (24.4±12.3 ind m-2 and 0.020±0.005g m-2), respectively which were significantly different (N=57, t=0.99, p<0.05). Spatial distribution of P. jenkinae among sampling stations (S1, S2 and S3) showed significant differences (N=57, t=0.99, p<0.05). Freshwater stations (S1) within the river showed higher density and biomass (112.1±64.8 ind m-2 and 0.082±0.035g m-2) than semi-brackish stations (S2) within the estuary (18.8±10.3 ind m-2 and 0.013±0.005g m-2). Semi-brackish stations (S2) showed higher density and biomass than brackish stations (S3) within the sea (0±0 ind m-2 and 0±0g m-2). Density and biomass of this species in Cheshmehkileh River and estuary was more than Sardabrood. A significant correlation (N=57, r=Pearson, p<0.05) between density and biomass of P. jenkinaewith environmental variables was found.

Habitat-Associated Morphological Divergence of Gasterosteus aculeatus in the Southern Caspian Sea Basin

Habitat-associated morphological divergence of the three-spined stickleback, Gasterosteus aculeatus populations was investigated in the southern Caspian Sea basin using landmark-based geometric morphometric method to understand the population structure of this invasive species. A total of 127 specimens were collected from three stations, including the Babol River estuary (center), Gomishan Wetland (east) and the Gisum Coast (west). The left side of each specimen was photographed and 23 landmarks-points were selected to extract body shape data. After generalized procrustes, the data analysis was analyzed using principal components analysis, multivariate analysis of variance/canonical variate analysis and cluster analysis. The results showed a significant difference in body shape between three studied populations (P < 0.001), that were related to the depth and length of the head, the body and caudal peduncle and the positions of the pectoral and ventral fins. Morphological differences of the studied populations can be considered as response to environmental characteristics of their habitats, showing G. aculeatus as a highly successful exotic species to expand its distribution area in the Caspian Sea.

Taxonomic status of six populations of the Gobiids (Teleost, Gobiidae) in the southern Caspian Sea basin using COI gene

Taxonomic status of six populations of the Gobiids (Teleost, Gobiidae) in the southern Caspian Sea basin using COI gene

Identification of Establishment Risk and Potential Invasiveness of Non-Native Fish Species in Anzali Wetland, Iran, Using the Freshwater Fish Invasiveness Screening Kit (FISK) and Climate Matching Model (CLIMATCH)

Predicting establishment and invasiveness risks of non-native (NN) species are fundamental aspects in the development of preventing measures and management plans. The main aim of the present study was to identify potential establishment rate and invasive of NN fish species using the Freshwater Fish Invasiveness Screening Kit (FISK) and climate matching model (CLIMATCH) respectively. The Anzali Wetland Complex (AWC) was selected as risk assessment (RA) area which is located in the southern Caspian Sea basin. Overall, fifteen NN fish species were assessed in the RA area. Receiver Operating Characteristic (ROC) curve showed that the two models identified reliably high potential establishment rate and invasive NN fishes in the RA area. FISK and CLIMATCH were calibrated to produce RA area-specific threshold values. The threshold values were 11 and 0.87 for FISK and CLIMATCH, respectively. FISK and CLIMATCH categorized 73.3 and 60% of NN fish species as high invasive risk and high probability of establishment, respectively. Six out of 15 NN fish species (i.e. Carassius gibelio, Cyprinus carpio, Gambusia holbrooki, Hemiculter leucisculus, Gasterosteus aculeatus and Pseudorasbora parva) that were assessed to pose both high risk of being invasive and high probability of successful establishment in the AWC. The results suggest that the FISK and CLIMATCH can be an effective decision-support tools for identifying potential high risk NN fish species in the wetlands connected to the Caspian Sea.

Morphological variation of Transcaucasian chub, Squalius turcicus in southern Caspian Sea basin using geometric morphometric technique

This work was conducted to study the patterns of morphological differences in body shape in Squalius turcicus De Filippi, 1865 from the most east (Atrak River) to the most west (Aras River) populations of the southern Caspian Sea basin using landmark-based geometric morphometric method to understand how the body shape alters in relation to geographical alternations or environmental characters of their habitats. A total of 102 specimens were collected from the Aras, Tajan, Atrak, Ghareh-Su, Khyer and Sefid rivers and after anesthesia, their left faces were photographed. To extract shape data, 14 homologous landmark-points were digitized and data after generalized procrustes analysis, analysed using principal component analysis, canonical variate analysis, cluster analysis, and Mantel test. The results showed significant differences between the body shape of six studied populations, mostly related to snout, base of the dorsal and anal-fins, body depth and pectoral fin position as result of phenotypic plasticity to the environmental features of their habitats. The Tajan and Atrak populations have a higher and lower body depth, and the Kheyr population a longer snout.

Landmark-Based Morphological Differences Among the Exotic Rhinogobius lindbergi and Its Two Sympatric Gobies (Actinopterygii: Perciformes: Gobiidae) in Sefid River, in the Southern Caspian Sea Basin

Introduced species may cause harm to native fish populations, which to design any conservative program to control the exotics an identification key is necessary. To find the morphological differences among the exotic Rhinogobius lindbergi and its sympatric congeners including the endemic Ponticla iranicus and the native Ponticla gorlap, a 15-landmark morphometric system was used to examine 90 specimens in Sefid River, in the Southern Caspian Sea basin. Univariate analysis of variance showed significant differences among the means of the three groups for 79 out of 105 standardized morphometric measurements. Principal component analysis (PCA) and canonical variates analysis (CVA) confirmed the statistically significant difference among these species. The CVA scatter plot showed that the 90 studied specimens grouped into three distinct areas with a degree of overlap between P. iranicus and P. gorlap. Clustering based on Euclidean distances among the groups of centroids using an UPGMA indicated segregation of the three species into two distinct clusters: P. iranicus and P. gorlap in one group and R. lindbergi in the other group. The exotic Rhinogobius can be distinguished from the sympatric gobies in Sefid River by short snout (vs. longer), deep body (vs. shallow), deeper head, stout body, and smaller ventral disc.

Ichthyodiversity in the Anzali Wetland and its related rivers in the southern Caspian Sea basin, Iran

The Anzali Wetland is one of the most important water bodies in Iran, due to the Caspian migratory fish spawning, located in the southern Caspian Sea basin, Iran. During a long-term monitoring program, between 1994 to 2019, identification and distribution of fish species were surveyed in five different locations inside the Anzali Wetland and eleven related rivers in its catchment area. In this study 72 fish species were recognized belonging to 19 orders, 21 families and 53 genera, including 66 species in the wetland and 53 species in the rivers. Among the 72 identified species, 34 species were resident in freshwater, 9 species were anadromous, 9 species live in estuarine and the others exist in different habitats. These species include 4 endemic species, 50 native species and 18 exotic species to Iranian waters. The number of species in different locations inside the Anzali Wetland was comparatively similar while it had high variation in different rivers. Twenty fish species are new records for the Anzali Wetland basin, including 10 estuarine, 5 ornamental, 2 riverine, one anadromous, one euryhaline and a small exotic fish.

Occurrence of dactylogyrid and gyrodactylid Monogenea on common carp, Cyprinus carpio, in the Southern Caspian Sea Basin

In this study, we genetically characterised Monogenea found on common carp in Iran. In total, 5603 parasites were recovered from 112 fish. The parasites were first identified morphologically as Dactylogyrus extensus, D. anchoratus, D. vastator, D. minutus, D. achmerowi and Gyrodactylus sprostonae. Representative samples were then subjected to sequencing. This is one of the first studies which has provided both morphological and sequence data for Dactylogyrus spp. and G. sprostonae. Our findings provide a foundation for future research into the genetic make-up of these economically significant parasites and the establishment of effective strategies for their control and prevention in aquaculture systems.

Reproductive biology of the invasive sharpbelly, Hemiculter leucisculus (Basilewsky, 1855), from the southern Caspian Sea basin

The sharpbelly, Hemiculter leucisculus , an invasive species, has expanded its range throughout much of Asia and into the Middle East. However, little is known of its reproductive information regarding spawning pattern and season that could possibly explain its success as an invasive species. This research is the first presentation of its reproductive characteristics, which was conducted based on 235 individuals collected monthly throughout a year from Sefid River, in the southern Caspian Sea basin. Age, sex ratio, fecundity, oocytes diameter and gonado-somatic index were calculated. Regression analyses were used to find relations among fecundity and fish size, gonad weight (Wg) and age. The mature males and females were longer than 93.0 and 99.7mm in total length, respectively (+1 in age). The average egg diameter ranged from 0.4mm (April) to 1.1mm (August). Spawning took place in August, when the water temperature was 23 to 26°C. Average gonado-somatic index values for females at the beginning of the reproduction period (March) and in ripe mature spawning females (August) were 2.90% and 16.97%, respectively. The averages of absolute and relative fecundities were 19978.6 and 607.1 eggs, respectively. The absolute fecundity was significantly related to body weight, ovary weight and age. A potentially high reproductive capacity, comparatively small eggs, short time of eggs’ development, fast sexual maturation, short life span, tolerance to a wide range of environmental conditions, all promote the invasion of this invasive sharpbelly in freshwater ecosystems of the temperate climate zone.

A new fish based multi-metric assessment index for cold-water streams of the southern Caspian Sea Basin in Iran

Numerous riverine ecosystems in Iran are currently suffering due to various human activities, which are directly affecting the physico-chemical conditions of running waters and influencing the aquatic biota. In this study, we chose the cold-water streams of the Southern Caspian Sea Basin in Iran to analyse human pressures and develop a multi-metric fish index for the cold-water streams dominated by brown trout, Salmo trutta in this Basin. To do this, the fish and environmental data were sampled in 67 medium sized streams in the Caspian Mountains. In total, nine fish metrics were calculated. Moreover, 27 criteria describing major anthropogenic pressures for the entire sampling area were used to generate a regional pressure index that accounted for potential effects of multiple human pressures. For the index development, we first defined reference sites and then quantified differences of fish metrics between the reference and impacted sites. The multiple linear regressions were used for describing metric responses to natural environmental differences in the absence of any human pressures. Finally, by testing the ability of each metric for discrimination of impacted and reference sites as well as their sensitivity to a gradient of regional pressure index, the metrics density of brown trout and biomass of sub-adult brown trout explained human pressures best. Our multi-metric fish index performed well in discriminating between reference and impacted sites, giving a significant negative linear response to a gradient of regional pressure index. In general, the development of such an index offers an opportunity to enhance national bio-monitoring programmes in Iran.

How the body shape changes by the habitat hydrological factors in freshwater benthic fishes; case study on the genera Cobitis (Cobitidae) and Ponticola (Gobiidae)

Benthic fish groups with low mobility are often restricted to a narrow range of a stream course, and their morphological characters tend to be affected substantially by the environmental conditions in their habitat. Due to morphological affectability of fishes by many factors in lotic ecosystems, a landmark-based hypothesis was used to investigate the effects of habitat hydrological conditions on morphological characteristics in freshwater benthic fishes; a case study on the genera Ponticola and Cobitis . A total of 216 gobies and 128 spined loaches specimens were caught from six rivers with different hydrological conditions, along the southern Caspian Sea basin. In discriminant function analysis (DFA), the overall assignment of gobies and loaches into their original groups were 95.7% and 80.5%, respectively. Discriminant analysis for pairwise groups shows a longer snout, shallow body/head, and elongated body for populations living in the large slope channel with faster water velocity versus relatively short snout and deep body/head for those living in small slope channel with slower water velocity. The results confirm the possibility of changes in the morphological characters of the benthic gobies and loaches, which should be considered in taxonomical and biological studies.

Age, growth, sex ratio, spawning season and fecundity of Capoeta razii from Sefidroud River in the southern Caspian Sea basin

Some aspects of reproductive biology of Capoeta razii , an endemic cyprinid species from the Sefid River in the southern Caspian Sea basin, were studied by monthly sampling throughout a year. Age, growth, sex ratio, spawning season, fecundity, gonado-somatic, modified gonado-somatic and Dobriyal indices were estimated. The sex ratio (F: M) was obtained as 1.00:2.63, and the percentage of males was greater than females. The mature males and females were longer than 88 and 148 mm in total length, and 1 + and 2 + in age, respectively. The spawning of C. razii took place from late May to late August when the water temperature was between 19.7 and 22.8 ◦ C. At the beginning of the reproduction period, the average gonado-somatic index values were 10.0% ranging from 4.03% to 15.90% in ripe females. The estimated gonadal indices showed that the ripe males were ready to spawn earlier than females. The average egg diameter was 0.99±0.65, ranging from 0.2 to 2.3 mm. The averages absolute and relative fecundity were 4386±2174 and 66.3±37.8, respectively. The absolute fecundity was significantly related to body weight and gonad weight.