فهرست مطالب مسعود ستاری

Introdution: Light is one of the most important environmental factors influencing the physiological activities and growth of living organisms, including various fish species. Sterlet sturgeon, Acipenser ruthenus is a sturgeon species native in northern latitudes with shorter light periods, however, due to high performance in rearing, it has been distributed in different regions of the world with different latitudes.
This study was carried out to examine the effects of various photoperiods on growth indices and survival rate of female sterlet sturgeon broodstock. A total number of 36 fish, 1166.78 ± 248.35 g in average weight, were distributed in 12 concrete tanks in 6 treatments each with two replicates and 3 fish in each tank. They were reared under six different photoperiods for 12 weeks, including natural light (LDN), constant darkness (0L:24D), 8 h light and 16 h darkness (8L:16D), 12 h light and 12 h darkness (12L:12D), 16 h light and 8 h darkness (16L:8D), and constant light (24L:0D). Fish biometrical characteristics were measured and growth performance was evaluated every 4 weeks  intervals.
The results showed a significant difference in weight gain (WG) among different treatments from the 8th to 12th weeks. The highest WG was 70.00 ± 26.34 g in treatment 8L:16D. In addition, the treatments of 16L:8D and 24L:0D exhibited significant differences with the constant darkness and 12L:12D from the 8th to 12th weeks of the experiment. The lowest and highest body weight increase (BWI) were observed in the constant darkness and 16L:8D, respectively. The highest specific growth rate (SGR) was observed in the 16L:8D, while the lowest was found in the constant darkness. From the 8th to 12th weeks of study, the lowest food conversion ratio (FCR) in different treatments was attributed to the constant darkness, with significant difference with other treatments. At the end of the experiment, even though the WG, SGR, and FCR indices displayed better conditions in the constant light, however, the differences were not significant (p>0.05). The condition factor also did not exhibit any significant difference among different treatments throughout the experiment. The survival rate was 100%.
Based on the obtained results, the light regimes affect the growth of female sterlet sturgeon broodstocks, however, it was not significant. The lowest growth and the highest FCR were observed in fish reared in constant darkness. Although sturgeons are among benthopelagic species and do not depend much on the vision to find food, light can affect their growth performance. This study was conducted at the low temperature of the optimal feeding range for sturgeons. Obviously, at a higher temperature, the growth of fish can be increased and the possibility of a greater weight differences in various light regimes may be achieved. It seems that alterations in the photoperiod and increasing the illumination affect the secretion of hormones involving in the metabolism as well as enhance the sterlet sturgeon appetite and ultimately improve the ability of food convertion.
Although the effects of light on feeding and growth of female sterlet sturgeon in short periods were not significant, light and increasing the duration of illumination can enhance the efficiency of feed and growth. Further studies can be suggested at a longer period in order to optimize the rearing conditions of this species in different latitudes.

This study aimed to produce a smart infection warning film based on chitosan and gum arabic containing anthocyanin (0.5, 0.75, and 1 g) as a wound infection warning. Chitosan/gum film was prepared in a ratio of 1:2 with different doses of anthocyanin pigment (0.5, 0.75, and 1 g), and the control sample was considered without anthocyanin. The prepared film was evaluated on Pseudomonas and Mannitol salt agar media. To evaluate the functional properties of the prepared film, the amount of moisture, solubility, thickness, and water absorption of the treatments were measured. The lowest and highest film moisture content were in the control treatment, and the treatment contained 0.75% anthocyanins, respectively. As the percentage of anthocyanin increased, the thickness and solubility of the samples decreased significantly. Regarding the water absorption test, the highest amount was related to the treatment containing 1% anthocyanin, and the lowest amount belonged to the control treatment. To evaluate the effect of chitosan or gum film containing anthocyanin on the culture medium when the bacteria were well grown, chitosan or gum biofilms containing different concentrations of anthocyanin were cut to 1.1 cm and cut into It was placed on the culture medium for 60 minutes, and the color change of the films was checked with a colorimeter. The highest rate of color change of films in culture medium containing Pseudomonas aeruginosa was obtained in the treatment containing 0.5%; however, in the case of Pseudomonas aureus, the highest color change was observed in the treatment containing 1%. Finally, the best film in terms of physical characteristics is the 1% treatment, and in terms of color change in response to the growth of Pseudomonas, it is 0.5%, and for Staphylococcus aureus, it is 1%.

Species diversity of macrobenthos in Fusheh River, in Guilan Province, North Iran was studied and biological indices developed based on macroinvertebrates were used to evaluate the health status of the river. Macrobenthos sampling in the river was carried out at 4 stations on a monthly basis beginning from May to December 2016 using a Sorber sampler (mesh size of 300 μm and surface area of 900 cm2) with three repetitions. The sampled macrobenthos were preserved in 96% ethanol and transported to the laboratory for identification. A total of 4928 individuals from two phyla of Arthropoda and Annelida, three classes of insects (Insecta), crustaceans (Crustacea) and Clitellata as well as 8 orders (including Ephemeroptera, Trichoptera, Plecoptera, Diptera, Coleoptera and Haplotaxida) along with 25 families and 31 genera were identified. The most abundant genera were Simulium sp. (35.84-46.65%), Hydropsychae sp. (15.79-33.36%) and Baetis sp. (7.87-17.66%). Parameters of total abundance, EPT richness, EPT percentage and EPT/CHIR ratio were also calculated. The EPT richness showed a significant difference in monthly samplings (p<0.05). The presence of species sensitive to pollution such as Perla sp., Isoperla sp., Chloroperla sp., Oligoneuriella sp., Heptagenia sp., Rithrogena sp., Epeorus sp., Rhyacophila sp. and Philorus sp. belonging to orders Trichoptera, Plecoptera and Ephemeroptera exhibits both the good quality of river water and the desirability of species and genera as natural food for the river fish species.

The study was conducted to determine the concentrations of some elements and heavy metals including aluminum, cadmium, chromium, copper, nickel, lead, strontium, silicon, arsenic, antimony, cobalt, manganese, molybdenum, iron and zinc in edible (muscles, gonads) and non-edible tissues (Liver, kidney, skin) of the Caspian Roach (Rutilus rutilus caspicus) caught from the Caspian Sea in Guilan Province. 65 fish were collected from 3 fishing regions e.g. Astara, Anzali and Kiashahr from 2017-2018. Digestion process followed standard method procedures. Samples were digested and concentration of elements was measured by ICP-OES Perkin Elmer Optima 8300 atomic absorption spectrometer using standard Australian Geostats solution. Mean concentrations of Al, As, Cr, Cu, Fe, Mn, Sb, Si, Sr, and Zn were 1.007, 0.3, 0.33, 2.21, 12.78, 0.57, 0.78, 1.26, 1.97 and 11.5 μg/g respectively. Concentrations of Cd, Co, Mo, Ni and Pb were not detectable. Iron, showed significant difference in various tissues (p <0.05), but other metals did not differ significantly between tissues (p <0.05). Metal selective index (MSI) was Fe> Zn> Cu> Sr> Si> Al> Sb> Mn> Cr> As. Comparison of metal concentration with international standards showed that muscles of Rutilus rutilus caspicus is healthy for consumption. However, if metal contamination of the Caspian Sea is not managed, there is high potential for metals concentration exceed the safe levels. National and provincial decision makers, especially the Environmental Protection Organization (EPO), should invest more resources and control over industrial and agricultural activities, as main paths for pollutants entering the Caspian Sea. Severe and appropriate measures should be taken to make them comply with environmental standards.

The presence of microplastics (less than 5 mm) in marine environments, owing to their persistence and risk imposed to marine communities has become a growing global concern. Considering the hazardous nature of microplastic particles to benthic communities and commercial species of the Caspian Sea, the study was conducted to investigate the distribution of microplastics in sediments of the southern shores of the Caspian Sea. Sediment samples were taken by a Van Ween grab as sampling sites located in Astara, Bandar Anzali, Kiashahr, Rudsar, Sari and Turkmen port during the winter 2018. Sari station with an average of (340±20 items/kg dry sediment) had the highest and Turkmen port station with (156.66±75.71 items/kg dry sediment) had the lowest microplastic frequency. The size of the microplastics varied from 0.2-9.2 mm and most of the microplastics found (35.54%) were 1-2 mm in size. The extracted microplastics were mainly filamentous although fragment microplastics and films were also observed. In the studied samples, high color diversity was observed and blue (63.85%) and brown (20.31%) had the highest frequency. Using ATR-FTIR analysis, 4 types of polymers including cellophane, polyethylene, polypropylene and polyvinyl acetate were identified. The most abundant microplastics identified were cellophane. This study is among very few studies on microplastic contamination in the sediments of the southern Caspian Sea and the obtained results vital for further studies.

Determining the age and growth of fish is vital in fisheries management and biology. This information is the foundation for modeling aquatic population dynamics and is employed to analyze fishing data. The relationship between length and weight and some other growth indices of Caspian Vimba persa was studied from autumn 1996 through spring 1997 on the southwestern coasts of the Caspian Sea (Astara, Anzali and Kiashahr).

Sampling was carried out seasonally using beach seine net at three fishing regions e.g., Kiashahr, Astara and Anzali. Each season 8 samples were taken at designated sampling stations (a total of 24 fish each season) except for 9 samples at Anzali stations in the autumn (25 samples in total). In total 73 specimens of Caspian Vimba persa were collected from the sampling stations.

Fish age varied in the range of 0+- 3+ in both females and males. The highest length frequency was observed in the length group of 14-25cm. Mean total length in the whole population, females and males were 18.05± 2.38; 18.61± 2.73 and 17.14±1.29 respectively. Mean total weight in the whole population, female and male were 65.62 ±33.98; 73.89± 39.43 and 52.32±15.78 respectively. Mean fork lengths in the whole population, female and male were 16.05± 2.66; 16.68±2.49 and 15.46± 1.17 respectively. Mean gonadosomatic index was 6.88 ± 4.23. Mean hepatosomatic index and obesity coefficient were 0.98±0.51 and 1.04±0.10 respectively.

Analysis of the obesity coefficient showed that the species upholds ‘good’ growth rate.  The Length-weight relationship for the whole population was W = 0.3403L3.403, female W= 0. 003 L3.365 and male W= 0.0047L3.2719. The t test showed that the obtained bvalue was greater than 3 thus the species has a positive allometric growth pattern. Since within the whole sampled fish the W> L3 and CF = K> 1 (obesity coefficient was greater than 1) relationship was applied, it can be concluded that the Caspian Vimba persa are more obese than usual which indicates good feeding condition of fish in the southwestern part of the Caspian Sea.

The anesthetic effects of Valeriana officinalis (valerian) and Cymbopogon citratus (lemongrass) extracts and Eugenia caryophyllata (clove) powder were examined on juvenile sterlet sturgeon, Acipenser ruthenus to determine their optimal concentration to evaluate the possibility of these extracts as a potential replacement for clove tree flowers. In this study sterlet juveniles averaged 86.2±11.7g in weight and 29.7±1.05cm in length were exposed to 45, 60, 75 and 90 mL/L valerian extract, 3, 5, 7 and 10 mL/L lemongrass extract and also 2000, 3500 and 5000 mg/L clove powder by immersion method. The Results revealed anesthetic effects of all three compounds on sterlet sturgeon. Considering the time required for anesthesia and recovery, the 60mL/L, 5mL/L and 3500mg/L doses were determined as optimum concentrations for valerian and lemongrass extracts and clove powder, respectively. Since the valerian and lemongrass extracts were very effective in inducing anesthesia in this study, their use as an anesthetic agent in aquaculture activities is recommended.

Benthic macroinvertebrate-based indices are suitable tools for assessment of stream health and human impacts on its biological integrity. Since Ghale Rudkhan River is an attractive tourist destination and its surrounding population is growing, its water quality was examined usning biological indicators. Macroinvertebrate samples were taken monthly by a Surber sampler (mesh = 300 µ and area = 900 cm2) at five stations from May to December 2017. Samples were preserved in ethanol 96% and transported to laboratory for analysis. Total abundance, EPT index, EPT richness and percentage,EPT/CHIR ratios were determined. In total 5134 macroinvertebrates that belong to 35 genera, 30 families, 10 orders, 4 classes and 3 phyla were identified. The highest EPT richness was observed at the station no. 4 in May (607 ind.m-1) and the lowest was at the station no. 5 in October (7 ind.m-1). The presence of pollution sensitive species such as Epeorus sp. Rithrogena sp., Rhyacophila sp., Isopela sp., Gomphus sp., Cordulegaster sp., Coenagrion sp., Oligoneuriella sp., Heptagenia sp., Philorus sp. in Ghale Rudkhan River indicated the optimal quality of the river water.

Growth pattern and some biological characteristics of Leuciscus aspius Linnaeus 1758, in the southern parts of the Caspian Sea were studied. Some 96 fish specimens were caught at Guilan, Mazandaran and Golestan provinces from October 2018 to September 2019. Fish were at the age classes of 1+ to 4+ years. The highest percentage of fish were at the age class of 2+ (33.72%), while the lowest at 4+ years (11.62%). Male/female age ratio was 0.68-1. Total length varied between 29-54 cm, fork length between 25-49 cm and the body weight was 213- 985 g. The mean total length was 38.91±5.57 cm, fork length 35.06±5.23 cm and mean weight was 639.74±87.27 g. The lowest growth coefficient rate was observed at the ages of 1-2, while the highest at 3-4 years. The mean condition factor (CF) was 0.87±0.22, hepatosomatic index (HSI) was 0.41±0.17 and gonadosomatic index (GSI) was 0.56±0.17. The length- weight relationship of all specimens was W= 0.0204 L2.7361, in males was W= 0.0189 L2.7648 and in females W= 0.0217 L2.8867. According to the obtained b values, the growth pattern of L. aspius was negative allometric meaning that weight and length growth did not follow similar rate. Length growth was faster which resulted in thin fish specimens. Moreover, condition factor below 1 (CF<1) reflects that L. aspius did not have favorable feeding ground in the study area which has led to lower growth. Factors like pollution, destruction of rivers, scarcity of food sources and overfishing could be responsible for these problems.

The relationship between length and weight and some biological characteristics of Tinca tinca (Linnaeus, 1758) in the Anzali Wetland was investigated. A total of 102 specimens of T. tinca were collected on monthly sampling intervals from spring to winter 2019. The mean total length of fish was 15.97±1.51, minimum 13 and maximum 22.5 cm. The fork length was 15.58±1.55, minimum 12.7 and maximum 22.3 cm. Mean fish weight was 62.64±21.15 g with minimum 30 and maximum 174 g. The obesity factor index was 1.49±0.18 in the whole population and 1.41±0.11 in males and 1.55±0.20 in females with minimum values in autumn and maximum in spring. Mean hepatic index was 1.05±0.76 for the whole population, 1.29±0.89 in males and 0.90±0.63 in females with minimum values in spring and maximum in autumn. The mean gonadosomatic index was 5.62±4.58 for the whole population and 3.35±2.1 in males and 7.02±5.12 in females with the minimum in winter and maximum in spring. The relationship between total length and weight for all fish was W=0.025 L2.8123, female W=0.0363 L2.6907 and male, W=0.0066 L3 .2724. According to the b value of the length-to-weight relationship, T. tinca in the Anzali Wetland has an isometric growth pattern indicating similar growth and length growth rate. In the present study, the obtained CF>1 was obtained indicating a proper feeding conditions of the species in the Anzali Wetland.

Occurrence and abundance of Microplastics (MPs) were studied in sediments of the Anzali wetland for the first time in spring 2018. Sediment samplings were carried out using Van Ween Grab. After density separation in saline solution, MPs were counted by a stereomicroscope. The number of MPs was at the range of 14-282 items/100g dry sediment (140-2820 items/kg dry sediment). Stations 10 and 9 with 282 ± 171.14 and 14 ± 3 items/100g dry sediment exhibited the highest and lowest contaminations, respectively. The MPs gathered during the survey varied in size from 0.3 to 5 mm, and those with 1–2 mm in size had the highest frequency (37.3%). The dominant shape of MPs was fiber; Followed by fragments and films. Red, black, and blue were the most abundant colors by 34.1%, 30.8% and 26.4%, respectively. In total, 5 microplastic polymers including polystyrene (PS), polypropylene (PP), polyester (PEST), polyethylene (PE) and poly acrylonitrile (PAN) were identified. This first work provides original data on the presence of MPs, determining their bioavailability to organisms as seafood, and then possible transfer to human. The results provide useful information for further studies.

In this study, 34 different elements, including toxic and non-toxic heavy metals in the liver, muscle, gonad, kidney and skin of the Alosa braschnikowi were investigated. also, the relationship between aggregation of these elements with growth parameters (age and length) and physiological indices (Condition Factor, relative weight and Hepatosomatic index) were investigated. Some 74 specimens of fish were caught during fishing season (2017-2018) were prepared from three stations Astara, Anzali and Kiashahr on the south-west coastlines of the Caspian Sea. trace elements detection was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-OES). The difference between the tissues was significant in terms of concentration of metals, so that the maximum mean of chromium, molybdenum and Strontium metals in muscle, aluminum, arsenic, barium, manganese, vanadium and nickel in skin, cadmium, cobalt, lithium and lead in the kidney, copper and iron were found in liver and zinc metal in gonad tissue. In all five tissues of muscle, skin, kidney, liver and gonad, the highest concentrations of metals were iron and the lowest concentrations of metals were barium, nickel and cadmium. Investigation of the association of metals concentration in tissues with growth parameters (length and age) showed that there is a significant positive correlation between arsenic, cadmium, cobalt, chromium, copper, iron, manganese, Strontium and zinc metals with the growth parameters, and the strongest positive relationship and significant between copper with age (p<0.05, r = 0.40). also, there was a positive correlation between arsenic, iron, aluminum, barium, chromium, copper, lithium, molybdenum, manganese, nickel, lead and strontium with the physiological indices, which had the strongest positive and significant relation between lithium metal and liver index (p<0.05, r = 0.57).

Bio-indicators is a method for assessing water quality. The responses of benthic macroinvertebrates to pollution are more reliable. These organisms vary in their sensitivity to environmental pollution. The objectives of the present study were evaluation of health status and pollution of the Ghale Rudkhan River using macro benthos richness, Hilsenhoff biotic index and Shannon- Wiener diversity index. Five sampling sites were selected. Samples were taken from May to November 2017. A Surber sampler (area 900 cm2, 300μ pore size)was used for sampling with three replicates in each site. Samples were preserved in ethanol 96% and transported to the laboratory. Total of 5134 specimens of macroinvertebrates belonging to 35 genera, 30 families, 10 orders, 4 classes and 3 phyla were identified. Aquatic insect larvae dominated the samples. The highest abundance belonged to Diptera, Ephemeroptera, Trichoptera and Plecoptera in a descending order. The highest and lowest Shannon diversity index (2.28 and 0.42) were observed in May (site 4) and September (site 3) respectively. Based on Hilsenhoff (HFBI) index the water quality at sampling site 1 (upstream), site 3 (before trout fish farm), site 4 (immediately after fish farm) and site 5 (downstream) was “Good” and at sampling sites 2 (in vicinity of the tourist complex) was “Fair”. Based on monthly assessments of these indexes the water quality state in May and October were Excellent and Fair respectively.

Length-weight relationship and some growth parameters of Rutilus kutum were studied. In total, 112 specimens of kutum were collected randomly from beach seines at the southern shores of the Caspian Seafrom October 2016 to May 2017. The mean (±SD) total length, fork length, and weight for the whole population were 38.58±8.14, 35.57±7.65 cm and 659.48±334.06 g, respectively. The minimum and maximum length and weight of fish in different seasons were 16.5 and 51cm as well as 45 and 1525g, respectively. The mean (±SD) gonadosomatic and hepatosomatic indices for the whole population were 4.67±5.28 and 7.86±5.83, respectively. Analyses of length-weight relationships showed a strong correlation between these two parameters (R2=0.90). The length-weight ratio in males, females and total population were W= 0.821 L2.4278, W=0.01 L3.0025, W=0.041 L2.6224,respectively. The t-test analysis showed a negative allometric growth pattern for males and the whole population, whereas females followed isometric growth pattern. The mean (±SD) condition factor (CF) were 1.10±0.41 in males, 1.01±0.11 in females and 1.07±0.35 in the whole population. The mean CF was higher in males in comparison with females, although the differences were not statistically significant.

Water quality of Fusheh River (Guilan province) was examined using macrobenthose density, Hilsenhoff Biotic index and Shannon Winner diversity indices. Four sampling sites were selected and monthly sampling was conducted from May to December 2017 with a surber sampler (area of 900 cm2, mesh size of 300 µ) with 3 replicates in each sampling site. The collected macroinvertebrate samples were preserved in ethanol 96% and transferred to the laboratory for enumeration identification. In Total 4928 macrobenthoses specimens were identified belonging to 2 phyla, 3 classes, 8 orders, 25 families and 31 genera. Insect larvae dominated the samples. The most abundant groups of macrobenthoses were Diptera (53.09%) and family Simuliidae. Trichoptera (28.44%) with dominant family of Hydropsychidae and Ephemeroptera (16.24%) and the dominant family of Baetidae. Based on tolerance scores assigned to each family considering their resistance or sensitivity to pollution the Hilsenhoff Biotic Index was calculated. The results obtained from this Index categorized the Fusheh River in GOOD (some organic pollution) water quality class.BMWP/ASPT Biotic indices categorized site 1 and 2 (upstream) in suspected to pollution, site 3 and 4 (downstream) in moderately pollution classes. According to the Shannon wiener index the sampling sites 1, 2 and 4 were relatively polluted and sampling site 3 was polluted (P≤0.05).

The present study was conducted in Electric Blue Cichlid Sciaenochromis fryeri in early larval developmental stages from the fifth day post hatching (DPH) until 51 DPH to determine day of transforming from embryo to juvenile. Morphological characteristics were evaluated by using ImageJ software. Allometric growth patterns were calculated based on the formula Y=aXb. Yolk sac depletion was occurred on day 9. Scales were developed on day 19 and finaly developed juvenile shape. allometric pattern of different body segments were calculated according to isometry, positive, and negative allometry. Positive allometry of head and tail prior to inflexion point and variation in allometric growth pattern in different body segment determine priorities of organogenesis for survival in fish early life history. The obtained results showed consistency between the larval morphological changes and development of organs related to sensory movements and larval behavior. Every morphological change in larvae displays the development and evolution of one of the organs involved in feeding, breathing, swimming and sensory organs.

Parasite effects on biometric characteristics of common carp, C. carpio from Anzali Wetland.

Identifying parasites in C. carpio and evaluating their effects on biometric characteristics of fish.

A total of 78 individuals were collected on the seasonal basis (from spring through winter 2016) from the wetland, transported to the laboratory and after biometry, dissected to recover parasites. Cestodes and trematodes were stained with alum carmine and nematodes were cleared with glycerin alcohol, then their prevalence, abundance and mean intensity were determined.

Thirteen parasite species including Ichthyophthirius multifiliis, Trichodina sp., Epistilis sp., Gyrodactylus sp., Dactylogyrus extensus,  Diplozoon nipponicum, Diplostomum spathaceum, Posthodiplostomum cuticola, Asymphlodora sp., Caryophyllaeus fimbericeps, Raphidascaris acus, Pseudocapillaria tomentosa and Lernea cyprinacea were identified. Epistylis sp., P. cuticola, Asymphlodora sp. and P. tomentosa are reported for the first time from C. carpio in Anzali Wetland. The average weight in healthy and infected fish were recorded to be from 23.68 ± 3.54g to 686.73 ± 100.28 g, and from 32.47 ± 4.51 to 633.62g ± 64.64 g respectively. The condition factor in healthy and infected fish was from 1.09 ± 0.50 to 1.17±0.03, and from 1.24 ± 0.13 through 1.19 ± 0.03 respectively. It was also true for gonadosomatic index which was recorded in healthy and infected fish from 0.45 ± 0.16 through 3.56 ± 3.54, and from 1.78±0.67 through 2.74 ± 0.62. The instantaneous growth rate was 1.25 in healthy  2+ and 1+ year old individuals, and 0.72 in 3+ and 2+ year olds, while it was 0.94 and 0.65 in the same-aged infected fish, respectively.

Parasites could induce some negative influences on the biometric characteristics of infected fish, decreasing their growth rate. So that, it is necessary to monitor the parasite communities continuously in the native and commercially important fish species in Anzali Wetland to protect them and prevent introducing infected fish into the adjacent fish farms.

The present study purposed to determine the dose- and time-dependent changes in digestive enzyme activity (lipase, amylase and protease) and intestine histopathological alterations in Persian sturgeon, Acipenser persicus after exposure to sublethal concentrations (0, 0.05, 0.1 and 0.2 LC50) of malathion for 7 days. Based on the results, the activity of lipase, amylase and protease levels substantially decreased in the fish exposed to malathion (P<0.05). These activities were significantly dose- and time-dependent (P<0.05) and the lowest was in 0.2mgL-1 at the end of the experiment. Histological studies of the processed tissues showed marked histological alterations than the control group. The pathologic lesions of the intestine included blood congestion, loss of epithelial cells, fusion of microvilli, loss of microvilli,  sloughing of epithelial cells, flattening of intestinal microvilli, vacuolization of cell cytoplasm, hypertrophy of epithelial cells, shrinkage of microvilli and also cell necrosis in muscular were observed exposure to sublethal concentrations of malathion. In most cases, the severity of changes follows a dose- and time-dependent manner. Results showed that low concentration of malathion (0.05 LC50) can pose undesirable alternation in Persian sturgeon fingerling, an economic species of the Caspian Sea.

Caspian kutum, Rutilus frisii </em>Kamensky 1901, is a commercially important fish species in the southern part of the Caspian Sea. All of the metal entered in the Caspian Sea. The pollution of this metal cause To create environmental problem. To address the issue, some 51 R.</em> frisii</em> specimens were caught at five different fishing regions (including Astara, Anzali, Kiashahr,) of the southern shoreline of the Caspian Sea from September 2017 through January 2018. An inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure heavy metals concentrations in fish tissues. The highest concentrations of calcium, manganese in muscle tissue, aluminum, barium, cadmium, cobalt, iron, potassium, sodium, sulfur, tin, tungsten and zinc in kidney tissues, arsenic, nickel, lead and rubidium in gonads, chromium, lithium, Magnesium, phosphorus, antimony, silicon, strontium, thorium and titanium in skin tissue, copper and uranium in liver tissue. The lowest correlation between Ni and Sr with the other elements reported in liver tissue and the lowest correlation between Sb, Ni and Mn with another elements reported in liver tissue.</div>

Length-weight relationship and some biological parameters of Alosa braschnikowi (Borodin 1904) were studied from coastlines of the Caspian Sea (Guilan Province, Iran). . A total of 103 fish specimens were caught on a monthly basis using gill-net and beach seine net from were sampled from three stations i.e. Astara, Anzali, and Kiashahr. The age range in females (1+-4+) was greater than that of males (1+-3+). The total length of the males and females were 18-42 and 19-42 cm, and the fork lengths were 16-38 and 16-39 cm, respectively. The length frequency varied from 30-34 cm. The weight of males and females were 45-570 and 50-810 g, respectively. The mean total length, fork length, and total weight were 29.26±4.70, 26.88±24.4 and 231.36±130.44 g, respectively. The mean gonadosomatic index of the whole population was 1.64±1.81, where the minimum and maximum values were observed in autumn and spring, respectively. The mean hepatosomatic index and condition factor for the whole population were 0.78±0.34 and 0.083±0.13, while minimum and maximum values were recorded in summer and spring, respectively. Considering that CF>1 is an indicator of good feeding condition, the CF values obtained in this study suggests poor feeding condition for the species. The relationship of total length-weight for the whole population, males and females were W=0.0029 L3.2954 (r2=0.91), W=0.0022 L3.3742 (r2 =0.89) and W=0.0052 L3.1409 (r2=0.93), respectively. T-test showed positive alometric (b>3) growth pattern for both sexes and the whole population.

I this study, morphological characteristics of two populations of Aphanius dispar from two sulfur springs of Ahram and Dalaki in Bushehr were compared investigated. Totally sixty specimens, 30 from each spring, were caught by cone net. The morphological results were first standardized by Beckham equation and then investigated by principal component analysis (PCA), discriminant function analysis (DFA) and clustering analysis (CA). Wilks' Lambda test was used to compare the differences observed in the studied groups. Among the 78 truss intervals analyzed, 42 intervals showed a significant in the populations of A.dispar in Ahram and Dalki rivers (P<0.05). The studied populations are distinguished especially by pre anal, body height, distance from pectoral fin to ventral fin, distance from pectoral fin to anal fin, caudal peduncle length, head length, pre orbital, pre ventral and dorsal length. Apparently, the morphological differences between the two populations signifies distinct stocks in the studied rivers.

The aim of this study was to evaluate the toxicity of iron oxide nanoparticles on the gill antioxidant defense system of juvenile common carp (Cyprinus carpio). The juveniles (17±0.6g) were exposed to different concentrations (10, 30 and 50.0 mg.L-1) of waterborne iron oxide nanoparticles for 0, 1, 7 and 14 days and then the levels of antioxidant enzymes activities including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) were evaluated in gills. The results showed that exposure to nanoparticles led to a significant increase in MDA levels and time-related changes in antioxidant enzyme activities (P<0.05). Therefore, the biomarkers such as antioxidant enzymes and MDA level can be used as a suitable index for monitoring oxidative stress in carp.

Knowledge on the fish species is important in habitat protection management. This study was conducted to compare the morphological characteristics of two populations of Rhinogobius similis from Hariroud basin based on landmark morphometric truss network system. A total of 60 individuals from Polkhatoun (30 specimens) and Tafrihgah dam (30 specimens) stations were caught by electrofishing 220 volts. 15 landmarks set were selected and 105 distances were measured between the landmarks on the left side of each specimen. Then principal components analysis and discriminate function analysis were applied to identify influential truss variables to differentiate between the two populations. Based on principal components analysis results, there were 15 principal factors in morphometric characters. The linear discriminant analysis gave an average percentage of specimens classified of 100% for morphometric characters indicating a high rate of correct classification of individuals into their original populations. These populations are distinguished especially by head shape, eye diameter, and pre-dorsal, pre-pelvic and pre-anal distances.

Parasite communities of pike (Esox lucius L. 1758) were calculated  in  Anzali Wetland along with evaluating  their impacts on biometric characticties of the fish host. A total of 4338 parasites from 11 diferent species were identified including: Ichthyophthirius mutifiliis (21.88%); Trichodina sp. (8.59%); Henneguya sp. (0.78%); Tetraonchus monenteron (60.94%); Diplostomum spathaceum (23.44%); Rhipidocotyle illense (9.37%);  Posthodiplostomum cuticola (0.78%);  Raphidascaris acus (41.41%); Rhabdochona helichi (8.59%); Eustrongylides excisus (2.34%) and Lernea cyprinacea (3.13%). The occurrence of  P.cuticola in E. lucius is  reported for the first time from Anzali Wetland. By increasing total length, the average weight of the infected fish raised from 26.54 ± 12.94 g to 472.39 ± 68.38 g, the condition factor (K) from 0.64 ± 0.11 to 0.66 ± 0.06 and the gonadosomatic index (GSR) from 0.15±0.55 to 0.75±1.88. In healthy fish, the instantaneous growth rate (G) in the age groups of 1+ to 0+ years old was higher (0.617) than in the other groups, while in infected fish, the instantaneous growth factor had fluctuations in different age groups. On the other hand, the age groups of 3+ to 2+ years old had the highest growth rate (0.773). There were significant differences between the prevalence of parasites and some biometric characticties in infected fish (p<0.05).

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.