The presence of water resources, particularly rivers, significantly influences site selection. Throughout history, settling near rivers has brought numerous advantages, but it has also posed certain risks. This study focuses on the sub-basins southeast of the Caspian Sea. Initially, we explore the connection between the layout of ancient settlements and the drainage networks. Additionally, we analyze the relationship between flood risk and the settlement patterns of these ancient sites by estimating the flooding risk based on linear, areal, and relief aspects. This reSearch marks the first time such an analysis has been conducted. The findings underscore the importance of proximity to rivers in site selection, with areas close to rivers with lower stream orders being the most favorable for settlements. The study reveals a decrease in the frequency of sites near higher stream orders in relation to flooding risk. Conversely, there is an increase in the frequency and density of ancient sites near the first stream orders and at greater distances from the rivers, coinciding with an elevated flooding risk in the sub-basins. These results indicate that the inhabitants of the Southeastern areas of the Caspian Sea sub-basins were cognizant of the flooding danger and factored it into their decision-making when selecting settlement sites

Magnetic susceptibility is one of the most important tools for monitoring the sediment composition during environmental studies. In this reSearch, in order to reconstruct the Caspian Sea level changes, magnetic susceptibility variations were used during the studies of 5 sedimentary cores (K1, K3, K5, K7, N1), collected from bottom sediments of Gorgan Bay. Samples were analyzed for grain size, total organic matter, carbonate content and magnetic susceptibility (MS). The results showed a close relationship between particle size distribution and MS magnitude due to variation in terrestrial influx, which was caused by Sea-level fluctuations in different times. This process increases with rising particle size and magnitude of MS simultaneously with Sea level fall and decreases during Sea-level rise. Moreover, no relationship between magnitude of MS and carbonate content was observed. It could be concluded that using magnetic susceptibility curves with other data, such as geological and historical data, could be suitable for the reconstruction of marine environments, especially in the near shore coastal area.

This study was carried out to investigate population dynamic of Caspian sand smelt (A. caspia) based on a monthly sampling in northern coast of Gorgan bay, between the estuary and canal of Khozeini, during its migration to coastal areas from March to September 2017. A total of 800 samples were collected using beach siene. Length frequency analysis revealed that there is significant difference between abundance of males and females, so that there was no male in some elder length groups. Length-weight relationship was W=0. 007L2. 906 for males and W= 0. 008L2. 846 for females, indicating negative allometric growth for both sexes. After fitting the regression using least square method, the relationship was W=0. 006L3. 002and W= 0. 005L3. 071 for males and females respectively. Electronic length frequency analysis (ELEFAN) using response surface analysis resulted Von Bertalanfy growth equation as for males and for females. Growth curves showed that length and weight increments occur up to age of 3+. 3 cohorts were observed for both sexes of the studied population. Natural mortality using Pauly's experimental equation calculated as 1. 640 for males and 1. 274 for females.

While the outcrop of crystalline basement rocks of the Gorgan Spur (GS), a single anticline located southeast of the Caspian Sea with an axis trending ENE and sloping WSW, is a clear indication of compression and uplifting, the GPS measurements of the Gorgan train station, located to the southeast of the Gorgan Embayment, show subsiding. The recent GPS measurements of some locations of the Iranian side of the Caspian Sea confirm the anti-clockwise rotation of the eastern part of the Caspian Sea, whereas the South Caspian Block (SCB) has a clockwise rotation. This paper also confirms that there is no real oceanic crust in the SCB, but that the continental crust has subsided and has got the physical character of oceanic crust due to enormous pressure of more than 20 km sediments. The SCB is the deepest part of the Caspian Sea, is located in its southwestern part and is subsiding from the Cretaceous onwards.

Caspian shad is a commercial fish of Clupeidae in Caspian Sea and biological characteristics of the fish has not been studied before. In the study, 180 specimens of the fish were collected from Southeast coasts of the Caspian Sea quarterly from November 2001 until June 2003 and beach seine and gill nets were used to catch them. Main purpose for the study was determining food items and feeding changes in fish age, sex, station and le Season after invasion of ctenophore (Mnemiopsis leidyi) in Caspian Sea. The fish had Fork length, weight and age, 103-232 (158.8±24.4) mm, 16-130 (52.2±20.6) g and 2-5 (2.64±0.7) years old respectively , If and Vacuity Index, Intestinal Relative Length and Index of Fullness of them were determined 12.8%,0.51 ±0.02 and 168.7±192.1 respectively. The study showed Alosa caspia caspia feeds on numerous food items and phytoplanktons (Rhizosolenia and Spirogyra) comprised about 4.5%, Zooplanktons (Foraminifera, Copepoda, Cirripedia, Bivalvia larvae etc.) comprised 95.0% benthic animals (such as Gammaridae) and bony fishes (larvae and eggs) about 0.5% of food abundance in its digestive tract. This study showed these zooplanktons are increase of Mnemiopsis leidyi in Caspian Sea, so Index of Fullness (IF) and growth the fish is reduced.

The stock status of most fisheries resources is not well-known, which is associated with limited data available for stock assessment. To overcome this gap, several data-limited stock assessment models, including the surplus production model, were applied to estimate stock status of these data-limited resources where no sufficient data is available to apply the conventional stock assessment models. To estimate MSY, catch and CPUE data for Cyprinus carpio caught from the Southeastern Caspian Sea were applied. Twenty-two years data (1999-2022) were analysed by SPM to estimate MSY. Three parameters including population growth rate (r), population carrying capacity (K), and initial biomass for an exploited population (Binit) required for estimating MSY were guessed 0.075 (/yr), 6952 tones, and 3500 tones, respectively by the catch-MSY model. The estimated MSY using these guessed parameters by SPM was 130 tones. While, estimated MSY using the repeated (multiple) starting points was 1320 tones. Phase plot indicated that the current status was both below the limited and the target biomass reference points. These illustrated the stock of C. carpio in the southeatern Caspian Sea is unsustainable and overfished. Since, survival of C. carpio depends the releasing hatchery reared juveniles to the wild, specific fisheries management should be applied to prevent the undersize catch and illegal fishing.

This study was carried out to determine age and growth of Caspian Roach (RutiLus rutiLus caspicus) in Gomishan wetland during November 1998 to May 2000. 240 female specimens and 306 male specimens were aged by scale count method. The growth was estimated based on Ford-walford method. The result showed that 8+ was the oldest age group for both sexes. The most abundant ages were 3-5 years. The maximum growth was observed between 1+ and 2+. The growth slowed down after 2+.  

The investigation of Neolithization Process is one of most important issues in archaeological literature in recent decades. However the spread of Neolithic life style to Marginal area such as Southeastern of Caspian Sea is interested to some Archaeologists. The Neolithization and spread of it was a long process that comprised economic, social and even ideological changes. Today, the archaeologists are utilized neo-diffusionism hypothesis to explain why spread Neolithic life style to east (North eastern of Iran and Central Asia) and west (Europa) of the Fertile Crescent. The Southeastern of Caspian Sea is a region which has very important in the studies of origin of Neolithic life style in northeastern of Iran and west central Asia. In spite of importance of south east of Caspian Sea in this field of studies, a little information is available about this transition process. The area was surveyed and excavated by C. S. Coon and C. M. McBurney in the late 1940’ s and early 1950’ s and 1960’ s. By occurrence of Islamic revolution of Iran, archaeological studies were encountered a long cessation in this region such other areas of Iran. The archaeological reSearch is restated in the area at the recent decade. The results of one of that reSearch has been published In volume 3, number 4 of the Archaeological ReSearches of Iran journal, entitled: Neolithic and Neolithization of the eastern Mazandaran lowlands: based on new archaeological surveys, written by Ramezani et al. publication of the mentioned article and some of the proposed ideas by its authors was reason for us to once again reconnaissance some well-known concepts such as Neolithization, neo-diffusionism hypothesis, and localization of the Neolithic process in the region. The present article has two sections. The first section, the article entitled: Neolithic and Neolithization of the eastern Mazandaran lowlands: based on new archaeological surveys, written by Ramezani et al. published in In volume 3, number 4 of the Archaeological ReSearches of Iran journal, was reviewed in a critical perspective. In this essay we criticized some parts of the article, most notably those concerning the data derived from the excavations at the four famous caves of the Southeastern of the Caspian Sea and their lithic and fauna materials. In the second section, in order to studies of Neolithization process, we are reviewed settlements, subsistence and paleo-climate data at the Southeastern of the Caspian Sea. In north and northeastern of Iran and western of Central Asia, The beginning of agriculture returns to Jeitun-Chakhmaq Culture which identified by Masson’ s excavations at Jeitun Mound and Masuda’ s excavations at Sang-e Chakhmaq mound. Then, Neolithization process of Southeastern of Caspian Sea was explained on the basis of present data (archaeological evidence, fauna data and climate changes). Based on archaeological data collected from the Mesolithic sites of the Southeastern of the Caspian Sea and concerning the proximity of this geographical region to the well-known candidates of the origins of early domestications (Zagros-Tauros and Levant), it sounds pale to announce that the Neolithization process was imported to the region, and the Southeastern Caspian Sea archaeological sites did not contribute to the domestication of any of the known plant and animal species. In addition, similarities between architecture, burial customs and artifacts such as rectangular single room buildings with limestone plastered surfaces and inside oven, clay figurines, lithic industries, small handaxes, use of obsidian from Jitun-Chakhmaq culture sites with per-pottery Neolithic sites of the Central Zagros region has been supported this idea. However, our information about the spread Neolithic to Southeastern Caspian Sea is low and imperfect. It is clear that the picture is complex and non-linear, involving different modes, such as migration, infiltration, acculturation, etc., all taking place simultaneously

An ongoing ecological study of the Caspian Sea, in a particular distribution, identifying the species composition and regional variations, seems to be necessary before any study. According to this, in the present study, the type of dominance of planktonic groups in Southeastern basin of the Caspian Sea (Golestan Province) was studied. For this purpose, sampling of planktonic groups was done once in September 2015 with 3 repetitions. The results of phytoplankton study showed that there are 4 orders, 4 families and 4 genera in the study areas, which constitute Euglenophyta (Euglena sp. 99. 9% density), Dinoflagellata (Procentrum sp. 99. 5% density) and Bacillariophyta (Diatum group. 100% density), the main phytoplanktons flora of the ecosystem, respectively. The Genus Euglena is the index of hypertrophic waters and is the first time that has been seen predominantly in the studied basins. The results of zooplankton study also indicate the destruction of this planktonic group (only 1 zooplankton of the species Keratella cochlearis from the genus Rotifera was observed), which is mainly due to the toxin produced by Euglena and the anaerobic conditions in the ecosystem. In general, the results indicate a critical quality status of the studied areas, the loss of high amounts of living fauna and flora and the dominance of toxic and inappropriate planktonic groups in the ecosystem.

Background and Aim: Duo to their Nutritional importance and contaminated by heavy metals, study on the health of aquatic products is important. Therefore, this study tries to cover studies which have been conducted cadmium and lead concentrations in Caspian withe fish (popular fish) in the southern coast of Caspian Sea during past 5 years, and finally provide recommendation for limitation consumption of it.Methods: The study was conducted the muscle tissue of 586 Caspian Withe fish that collected by various reSearchers in the southern coast of Caspian Sea. Concentrations of cadmium and lead in the studied species obtain from published paper in valid scientific journals during past 5 years. Finally, dietary consumption risk and limit, were assessed in stand point of Cd and Pb.Results: Mean concentrations of cadmium and lead were exceeded various national and international standards. Daily and weekly intakes were less than allowable dose suggested by related organizations. According to estimations, in stand point of cadmium and lead, adult people can consume (kg day-1) Caspian withe fish 0.21 and 0.75, and children 0.05 and 0.16, respectively without any non-carcinogenic effects.Conclusion: It seems, in stand point of Cd and Pb the current consumption rate of Caspian withe fish don’t have any health risk for consumers.