Iranian Journal of Ichthyology

Habitat suitability assessment of Luciobarbus capito (Güldenstädt, 1773) of ShahrBijar River, the South Caspian Sea basin, Iran

Hadi ASADI, Ayoub YOUSEFI JOURDEHI, Maryam MONSEF SHOKRI — Sun, 02 Aug 2026 00:00:00 +0000

Knowledge of habitat requirements of aquatic animals plays an important role in fisheries and protection programs of aquatic ecosystems. Hence, this study was conducted to investigate the suitability indices of habitat use and habitat suitability index (HSI) of Luciobarbus capito in its distribution range in Shahr Bijar River. A number of environmental variables, including elevation, water depth, river width, river slope, velocity, substrate type, average diameter of bed stone, riparian vegetation type, and the relative abundance of L. capito at 13 stations and three replications from downstream to upstream, were examined during September 2013. The results showed that L. capito mostly preferred upper stretches of the river with higher velocity, middle depth, lower width, and bedrock substrate (i.e., beds with boulder cover and grasslands), and its residential area was riparian compared with the available ranges. Habitat selectivity index for L. capito. showed that the elevation is 130- 220m, water depth 55- 89cm, channel width less than 12m, channel slope 0.5-2.3%, water velocity less than 2m.s-1, bedrock substrate, average diameter of bed stone larger than 35-75cm. The presence of these conditions, with an HSI of 0.798, indicates that the ShahrBijar River is an excellent habitat for L. capito.

The first report of fossil shark remains in the Aitamir Formation and determination of its precise age based on Foraminifera in the Behkadeh Razavi section, western part of the Kopet-Dagh sedimentary basin

Pouria VAEZNIA, Mohhamad VAHIDI NIA, Abdolmajid MOUSAVI NIA, Erfan KHOSRAVI — Sat, 05 Sep 2026 00:00:00 +0000

The Aitamir Formation is one of the most important Cretaceous units in the Kopet-Dagh sedimentary basin in northern and northeastern Iran. The dominant lithology of this formation consists of sandstone, olive-green glauconitic shales, and three coquina beds. The Behkadeh Razavi section is situated west of Ashkhaneh. In this study, a total of 44 fossil shark teeth were collected from the shaly deposits of the upper part of the Aitamir Formation near Behkadeh Razavi. After cleaning the samples, microscopic investigations and systematic descriptions were conducted, leading to the identification of four species across four genera: Ptychodus decurrens, Scapanorhynchus raphiodon, Cretodus crassidens, and Cretoxyrhina sp. Comparative analysis of these specimens with similar material from other parts of the world, along with the comparison of their relative ages and the fact that all specimens were discovered within the same stratigraphic horizon in the studied Aitamir Formation, indicates that the age of the fossil-bearing deposits is Cenomanian. The obtained age is in complete agreement with age determinations based on foraminifera. Furthermore, the presence of these fossils and their associated paleoecological implications provide important information for reconstructing the paleoenvironment.

Reproductive biology of the Caspian Shemaya, Alburnus chalcoides (Pisces, Cyprinidae), from the southern Caspian Sea basin

Mahsan SHAERI-ROUDBANEH, Hamid FAGHANI-LANGEROUDI, Hamed MOUSAVI-SABET — Sat, 05 Sep 2026 00:00:00 +0000

In the present investigation, some reproductive characteristics of Alburnus chalcoides were examined. Sampling of 195 specimens were carried out at monthly intervals from southern coasts of the Caspian Sea (Iran) through the year 2023. The sex ratio, fecundity, ova diameter, and gonadosomatic index (GSI) were studied. Sex ratio differed significantly from unity, in favor of females. The spawning took place from beginning of May to late July, when water temperature was 21-26°C. All stages of ovarian development were recorded macro- and microscopically. Spent fish were caught at five of twelve sampling times. The average egg diameter was 1.18mm. Average GSI value at the beginning of the reproduction period was 14.5% and ranged between 5% and 22% in ripe, mature females. The averages of absolute and relative fecundities were calculated 8064 and 135, respectively. The results of this study showed that the fish displays asynchronous oocyte development.

Life history characteristics of Threespine Stickleback (Gasterosteus aculeatus) from an estuarine area of the southern Caspian Sea, Iran

Rahman PATIMAR — Sun, 06 Sep 2026 00:00:00 +0000

To fill the knowledge gap on Caspian population of stickleback (Gasterosteus aculeatus), a total of 405 specimens caught near the mouth (in a distance of about 500m from the sea) of the Siahroud River (a small stream), and examined for the population-specific life history. The growth type was allometric negative for the studied population of the species. The stickleback’s lifespan was estimated to be 3.45 and 4.69 years for males and females, respectively. The Von Bertalanffy Growth Curve estimated as for males, and for females. The total mortality rate was 3.47 year^-1 for males, and 2.20 year^-1for females. Sex ratio was not significant from the ration 1:1. The reproduction period extended from April to June (late spring-early summer), with a peak in May. There were two kinds of ova, small colorless ova (0.43±0.08 mm) and large yolk-filled ones (1.16±0.29mm). Number of all ova ranged from 311 to 4709 and 128 to 885, respectively. The estimated absolute fecundity varied in a wide range from 235 to 5460 oocytes per ovary with a mean value of 1837.34±1028. The relative fecundity varied from 84 to 2441 eggs/g. The mean relative fecundity (eggs/g) was 799.