Acute toxicity of Diazinon to the Caspian vimba, Vimba vimba persa (Cypriniformes: Cyprinidae)

The present research was performed to determine lethal concentrations of diazinon for the Caspian vimba, Vimba vimba persa. Fish samples (50 ± 5 g) collected from Sefidroud river were acclimatized for 5 days and exposed to 5 concentrations of diazinon, 0.07, 0.08, 0.1, 0.13 and 0.16 mg/l (with three replicates) and lethal concentrations (LC) LC1, LC10, LC30, LC50, LC70, LC90 and LC99 for 24, 48, 72 and 96 h were determined using a probit analysis. The results indicated that the 96 h LC50 value of diazinon for Caspian Vimba was 0.08 mg/l

Benthic community structure in the Gorgan Bay (Southeast of the Caspian Sea, Iran): Correlation to water physiochemical factors and heavy metal concentration of sediment

Macrobentos frequency and biomass was investigated in the Gorgan Bay in 2011. Five sampling sites were chosen to collect benthos and sediment from the Bay using a Van Veen grab sampler. Samples were collected seasonally. Macrobenthos were indentified and their biomass was recorded. Sediment heavy metals concentration were measured using Atomic Absorption Spectroscopy. A total of 11 families belonging to three phyla of invertebrates were found. The phyla were Annelids (Nereidae, Naididae, Ampharetidae, Lumbriculidae, Tubificidae and Amphiporidae), Arthropods (Pontogammaridae, Balanidae and Chironomidae) and Mollusks (Cardiidae and Scrobicularidae). Lumbriculidae (413 individuals m-2, corresponding to 18.7%) and Cardiidae (55.2 g m-2, corresponding to 82.4%) had the highest frequency and biomass, respectively. Annelids with an average of 1557 individuals m-2 was the most frequent groups, while, mollusks with the average of 141 g per m2 had the highest biomass. Results showed that macrobenthos frequency in summer was significantly higher than those of the other seasons, however, in the case of biomass, there was a significantly higher biomass in the spring than the other seasons. The maximum metal concentration was related to Zn and Pb, whereas, Cr and Cd had the lowest values. There was no significant difference in Zn and Cr concentrations among the sampling seasons. Pb concentration in winter was significantly lower than the other seasons, whereas, Cd concentrations in the spring and summer were significantly lower than the autumn and winter. There were some correlations between benthos frequency and water physiochemical characteristics and sediment heavy metal levels. This study indicated that benthic fauna of the Gorgan Bay and the Caspian Sea are not similar. Also, results showed that benthic fauna communities are affected by sediment heavy metal concentrations and water physiochemical characteristics, however, different benthos groups show unsimilar relationship with heavy metal concentration

Microsatellite loci to determine population structure of Garra rufa (Heckel, 1843) in the Khuzestan Province (Iran)

Genetic diversity of Garra rufa was studied using 6 polymorphic microsatellite DNA loci. The specimens of G. rufa were collected from the Kheirabad and Maroon rivers. Despite high importance of this species, there is no genetic information about its population structure. A total of 133 alleles were detected at the 6 loci across the two populations. The Kheirabad population exhibited a lower genetic variation (Ho=0.429 and He=0.850) than the Maroon one. The average numbers of observed alleles in the Kheirabad and Maroon populations were 11.8 and 10.3, respectively. The genetic similarity and distance between the two populations were 0.721 and 0.326, respectively. It seems that Maroon population live under better conditions in contrast to the Kheirabad one. Diminution of genetic variation within examined populations decreases its adaptation to environmental alterations. Based on the results of this study, we can identify two different Garra rufa populations in the Khuzestan province

Reproductive season, maturation size (LM50) and sex ratio of Metapenaeus affinis (Decapoda: Penaeidae) in Hormozgan shrimp fishing grounds, south of Iran

This study aimed to investigate the spawning season, length at first maturity (LM50) and sex ratio of Metapenaeus affinis in the shrimp fishing grounds of Hormozgan Province, west of the Persian Gulf, Iran. Samples were taken by the swept area method and Trawl net with 2 cm mesh size in the cod end from January 2010 to February 2011. Results showed that the sex ratio deviated from 1:1 and female's number were significantly higher than males. Metapenaeus affinis females had continuous spawning in all seasons but the peak spawning season was found in spring, and stage 3 of maturity was observed in all seasons. Length at maturity (LM50) for females was estimated at 27.12 mm based on carapace length

Evaluation of water quality using TOPSIS method in the Zaringol Stream (Golestan province, Iran)

In order to evaluate water quality condition, biochemical oxygen demand (BOD), dissolved oxygen (DO), temperature, pH, turbidity, total suspended solid (TSS), phosphate (PO-4), nitrate (NO-3) and fecal coliform were measured seasonally from 9 sites from November 2009 to August 2010 in Zaringol Stream. Water quality condition was estimated using TOPSIS method. Comparison of TOPSIS values in different sampling stations showed the minimum (0.230) and maximum values (0.604) are in points 1 and 5 respectively. According this result, point 1 had the best water quality condition and point 5 had the lowest quality. Also, Seasonal results of TOPSIS values showed that the maximum value was found in spring. Discharge of effluents from land uses located along the stream specifically, trout farms and starting agricultural activity and production process in spring and summer are most important reasons for decreasing of water quality. TOPSIS estimates values ≤0.5 for almost stations and seasons. It shows Zaringol Stream has an average water quality.  

Effect of dietary free L-Lysine on growth performance and muscle composition of Beluga Huso huso (Linnaeus 1785) juveniles

Effect of dietary free L-Lysine on growth, food intake, and muscle composition of beluga juveniles were investigated over 6 weeks. Control diet lysine content was 2.1% of dry matter (4.4% of dietary protein). Three experimental diets were prepared by adding lysine (0.5, 1 and 1.5%) to control diet to obtain diets containing 2.6, 3.1 and 3.6% of dry matter lysine (corresponding to 5.5, 6.6 and 7.6 of dietary protein). Fish were fed 2.6% of dry matter lysine showed significantly higher final weight, weight gain and SGR and lower FCR compared to other treatments. There was no significant change in food intake and survival between treatments. Lysine supplementation resulted significantly in increase and decrease in muscle protein and lipid, respectively. Dietary lysine has no effect on muscle ash and moisture content. Results showed that lysine supplementation had no significant effect on food intake in beluga juveniles. It seems that dietary lysine level of 2.6% of dry matter (corresponding to 5.5% of dietary protein) is suitable for growth of beluga juveniles

Microsatellite variation and genetic structure of common carp (Cyprinus carpio) populations in Gomishan bay and Gorganroud River (Southeast of the Caspian Sea)

Common carp (Cyprinus carpio) population has been declined in the Caspian Sea in the recent years, mainly due to human manipulation. This valuable species needs to be protected in the Caspian Sea. Considering the commercial value of common carp, its rehabilitation program has been established. In the present study, 8 microsatellite loci were used to assess genetic variation and population structure of common carp in Gomishan bay (GB) and Gorganroud River (GR). These two regions are the most important habitat of common carp. Mean actual (Na) and expected (Ne) alleles numbers were 15.12 and 11.35 for GB and GR, respectively. Mean observed (Ho) and expected (He) heterozygocity were 0.99 and 0.90 for GB and GR, respectively. Results, also, showed that all investigated loci were polymorphic. Twelve out of 16 tested locusí—region combinations showed significant deviation from Hardy-Weinberg equilibrium (HWE) which could be mainly due to increase in He. FST index was found to be 0.011. Hence, AMOVA showed that observed variation was related to within population (99%) as well as between populations (1%). According to the results, it is suggested that studied populations have a great allelic richness and gene flow

Acute toxicity of two pesticides Diazinon and Deltamethrin on Tench (Tinca tinca) larvae and fingerling

Diazinon and deltamethrin are common useful agricultural pesticides in the world. The present research compared the acute toxicity of diazinon and deltamethrin to tench larvae and fingerling. LC50 of 24 h, 48-h, 72 h and 96 h were determined using a probit. Fish samples (21 fish in each test group) were exposed to different concentrations of diazinon and deltamethrin (diazinon: for fingerling between1-20 ppm and larvae 0.25-2 ppm, deltamethrin: for fingerling between 0.01-0.2 ppm and larvae 0.0025-0.02) for 96 h and mortality were recorded. The LC50 96 h of diazinon for fingerlings and larvae were 6.77 and 0.63, respectively. The LC50 96 h of deltamethrin for fingerlings and larvae were 0.07 and 0.005 ppm, respectively. According to the results, larvae are more sensitive than fingerlings, LC50 values indicated that deltamethrin is more toxic than diazinon to Tinca tinca, so we suggest to use diazinon instead of deltamethrin in agriculture

Age and sex specific variation in hematological and serum biochemical parameters of Beluga (Huso huso Linnaeus, 1758)

In the present study, the age- and sex-specific changes of various haematological and blood serum biochemical blood parameters of Beluga (Huso huso) were investigated. Blood samples were collected from 4-, 6-, 7-, and 8-year-old beluga (n = 7 for each sex and age). The specimens were fed at a rate of 0.5-3% body weight per day. AST and LDH levels in 7- and 8-year-old fish of both sexes were significantly higher (P<0.05) than those in 4- and 6-year-old individuals. The mean ALT were significantly different (P<0.05) in both sexes of 4-, 6-, and 7-year-old sturgeon. However, the 6-, 7-, and 8-year-old female sturgeon had higher ALP levels (P<0.05). Additionally, mean RBC, PCV, and Hb values were significantly higher (P<0.05) in 7- and 8-year-old females and males than the others. Two-tailed Pearson's correlation between the biochemical and haematological parameters obtained for beluga sturgeon indicated significant positive correlations between AST and ALP, AST and LDH, ALP and LDH, RBC and Hb, RBC and PCV, Hb and PCV, MCH and MCHC, and MCV and MCH. However, significant negative correlations were found between RBC and MCV and MCH. These results suggest that the blood parameters of beluga are influenced by age- and sex-specific factors