Some biological aspect of the smallest goby fish (Knipowitschia caucasica Berg , 1916) in Gorgan Bay, Caspian Sea

This research was conducted in Gorgan Bay in 1994. The results showed that spawning of Goby fish, in southern part of Caspian Sea in the area of Gorgan Bay, from early winter to early spring had been gradually. The biggest nun fish in length which caught was 46 mm. There was positive correlation between length and body weight in males and females and this ratio was higher in females than males. Fishes had positive algometric growth over all male to female ratio was 1-1.1. The range of relative fecundity was 290 to 550 eggs and in average 395.5 which was depended on the length of fish

Abundance and diversity of Clupeidae species in Mazandaran and Golestan coastal waters, north Iran

As part of the identification and distribution mapping of Clupeid fish in southern Caspian Sea, we studied abundance and species diversity of the fish in Mazandaran and Golestan Coastal waters during August-April 1999 to 2001. In the 336 specimens studied, four species were identified including Alosa braschnikowi, Alosa caspia, Alosa saposchnikowi and Alosa kessleri. The most abundant species was Alosa braschnikowii comprising 84.4% of the individuals and Alosa kessleri was the least abundant comprising 3.2% of the sample. We also traced an increasing trend in abundance of Alosa braschnikowii from east to west such that 43.8% of the fish found in Golestan Province waters and 56.2% in Mazandaran Province waters. The highest fork length and weight was recorded as 395 mm and 760.3 grams respectively for Alosa braschnikowi and the lowest was recorded for Alosa caspia with 110 mm and 109 grams respectively. In Alosa braschnikowi male were dominant and relative abundance of male and female in Mazandaran Province was 44.2% and 55.8% respectively. In Golestan, the relative male and female abundance of Alosa braschnikowi was 30.6% and 69.4% respectively. Female to male sex ratio in the A. braschnikowi was 1:1.26 and 1:2.26 respectively in Mazandaran and Golestan provinces. Overall female to male sex ratio was calculated as 1:1.6 for the species. The caught A. braschnikowi were in I+ to 6+ age groups with the 2+ group comprising 28.9% and 1+ and 6+ comprising 8.9% of the sample

Structure of macrobenthic invertebrate population in the southern coast of Caspian Sea for fish cage culture establishment

This research in line with fish cage culture plan in the southern coast of the Caspian Sea was carried out. Sampling was seasonally in 8 transects at the depth of 5-100 m from Astara to Torkaman areas in 2008-2009. The aim of this study was to investigate the distribution, abundance and biomass of macrobenthic invertebrate. The highest abundance and biomass were found in transects of Amirabad with average 10931.7±7301.4N/m2 and Astara with mean 86.2±160.3g/m2, respectively. This could be due to the presence of alien species into the Caspian Sea, Streblospio gynobranchiata in 2003 and is the dominant population of macrobenthic invertebrate concern up to 58.4% and increased of S. gynobranchiata (high power compatibility) and mussels of Cerastoderma glaucum (large size) is relevant, respectively. The abundance and biomass have fluctuations in different seasons and the highest abundance with average 6280.1±5693.1N/m2 and biomass with mean 66.1±126.9g/m2 was in winter and spring, respectively. A significant difference between abundance and transects (p0.05), significant difference between biomass and depth (p0.05) were found. Also, according to multivariate analysis of benthic invertebrate on the abundance at various depths revealed that depths of 5, 10 and 20 meters from the importance of certain fisheries in terms of frequency, abundance and biomass of the macrobenthic invertebrate, slope substrate, substrate, close to the beach, the accumulation of nutrients, Nursery ground, feeding ground and Spawning ground is important for different important species in the Caspian Sea. Therefore, the establishment of fish cage culture was recommended more than 20-meter depths according to the plans of fish cage culture in the southern coast of the Caspian Sea of the Iranian Fisheries Organization

Biosystematic study of (Clupeidae) Alosa in Mazandaran and Golestan province coastal waters

This survey is part of identification and determination of clupeidae (Genus Alosa), in southern Caspian Sea, Mazandaran and Golestan Province coastal waters during 1997-99. In this study, total of 336 fish samples were studied. The results showed that 4 species of clupeidae, belong to: Alosa brashnikowii (Borodin, 1904), A. caspia (Eichwald, 1983), A. saposchnikowii (Grimm, 1887) and A. kessleri (Grimm, 1887). For species identification two morphometric and morphomerestic factors were used. One of the important factors of morphometric is gill rakers and, A. braschnikowii had 20-40 with average of 30.93±6.11, A. caspia had 110-125 with average of 118.3±5.23, A. kessleri had 60-73 with average of 66.82±3.31 and A. saposchnikowii had 20-48 with of average of 32.83 ±4.93 percent gill rakers. Another important morphometric factors are percent ratio of eye diameter to total length. A. braschnikowii had 2.9-5.82 and average of 4.72±0.53 percent, A. caspia had 5.73-7.46 and average of 6.21±0.52, A. saposchnikowii had 6-9.33 and average of 7.3±1.8 percent and finally, A. kessleri had 4.27-6.48 and average of 5.46 ±0.71 percent

Reproduction, sexual maturity and fecundity of anchovy kilka (Clupeonella engrauliformis Svetovidov 1941) in Iranian waters of the Caspian Sea

Reproduction period, spawning peak and sexual maturity in anchovy kilka were investigated during the year 2006 for sustainable yield assessment in Iranian waters of the Caspian Sea. The mean fork length, total weight and age were 118±5.9mm, 11±1.7g and 4.6±1.2 year, respectively. Mean (±SD) absolute fecundity was 12625±5533 ovules. More than 50 percent of the fish specimens matured when their length exceeded 92.5mm. The results showed that reproduction of anchovy kilka occurred in autumn, and spawning occurred throughout the year and especially in winter. The length and age ranges were found to be shortened compared to the past years with many older fish and less younger ones (< 2 years) in the catch which sharply decreased recruitment. This phenomenon is thought to be due to overfishing synchronized with invasion of M. leidyi pushing kilka to spawn in winter, which all cause collapse of anchovy kilka stocks in the Caspian Sea. We postulate that anchovy kilka has adopted the strategy of spawning year round to mitigate the negative effects of overfishing and invasion of M. leidyi

Age and growth of bigeye kilka (Clupeonella grimmi Kessler, 1877) in Iranian waters of the Caspian Sea

Age and growth of Bigeye Kilka, Clupeonella grimmi, were studied in Iranian waters of the Caspian Sea from early May 2006 to April 2007. The sagitta otoliths were removed for each 5 mm length interval up to a total number of 262 fish. Fork length and weight ranged from 92.5 to 142.5 mm and 4.2 g to 23.4 g, respectively. The largest length-groups was observed from December to February and the lowest in April, which was coincided with spawning period and feeding during wintering, respectively. The overall sex ratio (male:female) was 0.33:1 which differed significantly from the expected ratio of 1:1. The length-weight regression was W= 0.0000744 FL^3.14 for females and W=0.0000341FL^3.16 for males, indicating the Caspian Bigeye grew isometrically for both sexes. Age determination based on otoliths readings showed that the population was composed of six- groups from 2 to 7 years old which observed a rapidly growth during the second year. In the age compositions, the four years old specimens with a mean fork length and weight 115.5±7.8 mm and 11.9 ± 2.8 g were the most abundant age group and accounted for 40.1%. The condition factor was 0.7-0.8 which varied in difference months and coincided to the gonad development. Age-at-length data were used to determine von Bertalanffy growth parameters for this population in both sexes, indicating that K value and L∞ of females was more than that of males. The results showed that C. grimmi is a rapidly-growing species in the southern parts of the Caspian Sea

Investigation and determination of some heavy metals in the Aras river fish species in the East Azerbaijan Province (2015-16)

This study was conducted to determine heavy metals (Cu, Mo, As, Hg) in fish species of Aras River (East Azerbaijan) at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. Thirty eight specimens of fish were collected by using of electrofishing as the main method for sampling. The amounts of heavy metals were measured by using an atomic spectrophotometer in the muscle tissue of specimens. Bioaccumulation factor was also calculated for each species. The amount of bioaccumulation factor for molybdenum was the highest and the arsenic had the lowest amount. The highest concentration of copper was in Barbus lacerta with a mean of 13.6 ± 11.3μg /g dry weight and for the molybdenum, Alburnoides bipunctatus had the highest mean concentration (11.7±4.9) μg / g dry weight. The average concentration of mercury (13.1 ± 1.5 μg / kg dry weight) was highest in Alburnus alburnus. Regarding the arsenic elements, as it was analyzed in a small number of specimens, the highest concentrations were recorded in Alburnoides bipunctatus. According to ANOVA, there were a significant difference between mean concentration of copper in different species (p<0.05) and the Duncan test has distinguished Alburnus alburnus from other species

Study on physico-chemical characteristics of Azad dam reservoir (Sanandaj) in order to fisheries activities

Dam reservoirs have important rules in aquaculture and fish farming in many countries. In this regard, water samples of Azad Dam reservoir (Sanandaj) were collected at five stations from July 2015 to June 2016. Then, the results of 18 physico-chemical parameters were compared with the aquaculture standards and thresholds. Results showed that thermocline and oxycline was started from June and they vanished in December. Maximum level of thermal and oxygen stratified were registered during August and June, respectively. Mean of the most physico-chemical parameters were significantly different between surface and bottom layers (T-Test, p<0.05). Mean of temperature, dissolved oxygen, total alkalinity, total hardness, pH, total suspended solid, total dissolved solid and nutrients were in range of standard threshold of different countries. As a result, based on physico-chemical parameters and with proper management decision, the dam reservoir could be considering suitable for standard pattern of aquaculture activities

Biological studies of fishes (Clupeidae, Rutilus frisi kutum, Liza auratus, Cyprinus carpio, Chalchalburnus chalcoides, Vimba vimba, Abramis brama, Sander lucioperca & Liza saliens) of southern Caspian Sea

During the past decades the environmental status of the Caspian Sea has changed. Therefore, study on the biological structure such as: age, growth, Lm50%, feeding of fishes is necessary. In the present study the biological characteristics of some commercial important species including kilka, kutum, golden grey mullet and carp were studied during 2006-2010. Kutum, golden grey mullet and carp predominated in the catch composition of bonyfishes, representing 61.3, 29.6 and 7.6% of the total catch. The average fork lengths of kutum, golden grey mullet and carp were 38.4, 32.7 and 36.7 cm, and weights were 784.5, 411.0 and 977.0 g, respectively. The values of b in length-weight relationships were 3.02 and 2.97 for kutum and golden grey mullet indicating an isometric growth. The value b for carp was 2.89, indicating an allomertic growth. The maximum age of three species was 12 years. Von Bertalanffy growth equations were estimated as: for kutum: for golden grey mullet: and for carp: The sex ratio of three species showed that females were dominant. Spawning migratory of kutum was started in March. The gonadosomatic index value of kutum peaked in March and April. The spawning season of carp expended from March to August. The gonadosomatic index value of golden grey mullet peaked in September and then declined in November and December. Absolute fecundity of kutum, golden grey mullet and carp were 64400, 700800 and 131000 eggs, respectively. Length maturity (Lm50%) of three species were 39.07, 28.4 and 31.6 cm, respectively. The highest feeding intensity (Gastrosomatic index=GSI) for females and males were 313.9 ± 65.9 and 350.7±103.7 in October; and the lowest value of GSI were 19.4 ±59.2 and 144.1±85.04 in March, respectively. There are significant different between GSI with male and female in difference months (P<0.05). Main prey mature of Kutum was Cerastoderma lamarki; Gastropoda and Balanus were subordinate, and Crab, Hypanis, Fish (Neogobous sp.) Algae, egg, and scale were random preys. Planktone groups comprise to Exuviaella, Nitzchia, Osillatoria, Synedra, Nematoda, Navicolla, Diatoma, Rholcosphenia were preys juvenile of Kutum. Based on ISI (Important species index), Cerastoderma lamarki and Balanus were dominant species in feeding of Kutum. The percent of empty stomach and prey dominant evaluated during different seasons by specific formula result showed that in Cyprinus carpio prey Molluscs was dominated and specific food items. Empty stomachs in winter and spring were higher and lower, respectively. The results showed that catch of kilka decreased from 22300 mt in 2006 to 16700 mt in 2008, but the CPUE increased from 1.7 mt (Vessel×Night) to 2.5 mt, due to decrease of effort, respectively. The length frequency of three species of kilka is close and the juvenile fish did not see in catch. The age frequency had the same situation as fish lower than 2 years was not in the samples of anchovy and bigeye kilka. The parameters of the von Bertalanffy growth curve were: For common kilka: L =136.5 cm, K=0.249 yr^-1 and t0= -1.89 yr^-1 for bigeye kilka: L =148. cm, K=0.346 yr^-1 and t0= -1.123 yr^-1 and for anchovy kilka: L =131.7 cm, K=0.375 yr^-1 and t0= -1.243 yr^-1 the exploitation rate of anchovy, bigeye and common kilka were 0.51, 0.58 and 0.6, respectively. The highest of GSI for common and bigeye was recorded in May and March, respectively. For anchovy kilka it was in July and November. Main prey of anchovy and common kilka was Acartia tonsa and for bigeye kilka it was Cypris balanus. We concluded that the ecological problems caused by Mnemiopsis leidyi as well as overfishing have been collapsed kilka stocks, particularly anchovy. Therefore, sustainable fisheries management and conservation biodiversity in the Caspian Sea are real challenges now

Investigation possibility culture of shrimp Litopenaeus vannamei with brackish water of Caspian Sea in Mazandaran Province

Whiteleg shrimp (Litopenaeus Vannamei) is one of the most important species for aquaculture development, because of tolerance and adaptation to different ecological conditions. The aim of this study was determine the bionormative parameters of vannamei shrimp culture using Caspian Sea brakish water in Mazandaran province and also possibility of introduction a new aquatic species for rearing in Mazandaran province. The Shrimp vannamei reared with the brackish water (10±0.43ppt) of the Caspian Sea in Mazandaran province and the Caspian Sea Ecological Research Iinstitute in summer 1391, 1393 and 1394. In this study, were evaluated the effect of different densities (45/m^2, 50/m^2, 55/m^2 and 60/m^2) primary stock whiteleg shrimp postlarvae (PL12) on the growth, survival rate and also population structure of phytoplankton in shrimp vannamei. Initially, post larvae in brackish water were gradually adopted. The density of 35 per square pieces in an earthen pond (1000m^2) was stocking. The rearing time was 85 days. Average daily growths: 0.31±0.037g; final mean weight: 21.11±0.71; Feed conversion ratio: 0.79 and final yield: 531kg were determined. In addition the experiment of 1391, the results of Mazandaran province vannamei shrimp culture, were observed in 1393 and 1394, the average weight average daily growing and FCR % were 20-18 g and 0.68 - 0.77 respectively during 90 days culture period with harvesting of 40 PL /m^2 at cement culture pond. The experiments of effect of different densities were performed separately in 1391, in 12 circular concrete pound with a sandy bed (area: 78m^2) in the four treatments and three replications for each treatment. The experiments performed in a 75-day period. During the test, the water temperature was 27.4±1.79°C. The results showed that growth parameters and survival rate in experimental treatments, there was a statistically different (Duncan test, P<0.05). Thus, with high levels of density, the amount of weight gain and survival rate (SR), specific growth rate (SGR) and daily growth rate (ADG) has decreased. In addition, the treatments were different variations of FCR (P<0.05) and not depend on the primary stock density of postlarvae. The highest growth (SGR=11±0.04 and ADG=0.25±0.01) and survival rate and calculate the amount of production per hectare (5596±433) were observed in low density (45m2). In this study identified 20 genera of phytoplankton from five division of the Phytoplankton. Phylum Cyanophyta, with 30 percent of the identified genera that much more constituted. And the phylum Chlorophyta with 25 percent, of Bacillariophyta 20 percent Pyrrophyta 20 percent and Euglenophyta 5 percent had the lowest frequency. Chlorophyta with 25 percent allocated to the division, with 20 percent of Bacillariophyta, with 20 percent of the division; Pyrrophyta Euglenophyta division with 5 percent had the lowest frequency. Euglenophyta phylum was identified as a species. Therefore, based on acquired results, was observed that, vannamie shrimp was reared well using Caspian Sea brakish water in Mazandaran province. In addition, it seems that, vannamei shrimp was gained better results in Mazandaran province compared to other provinces, because of suitable water salinity