Investigation on drought effects on diversity, frequency and distribution of benthic fauna in Amirkelayeh Wetland

The Possible effects of dry years 1998-2000 on benthic organisms of Amirkalayeh Wetland was studied in the year 2001. Six sampling stations were defined where we seasonally collected benthics organisms using a grab sampler. We identified nine benthic organisms belonging to class Hirudina and orders Odonata and Ephemeroptera and also six families Chironomidae, Chaoborina, Ammaridae, Tubificidae, Xanthidae and Culicedae. Families Xanthidae and Culinidae had not been reported before for the wetland while orders Coleoptera and Trichoptera and families Planorabidae, Limnaeidae, Coleoptera which were present before the drought, were not detected in the samples. We observed a significant decrease in frequency of benthic organisms changing from 1372 organisms per square meter in 1997 to 165 in 2001. Also, tests showed considerable change in benthic diversity, species richness and distribution in different sampling seasons and stations over the year 2001. These changes may be attributed to the decrease in water depth, dissolved oxygen, available food and increase in water temperature and predation

Species composition and abundance of fishes in Amirkelayeh Wetland

In order to determine the species composition and abundance of fishes in Amirkelayeh International wetland a series of seasonal survey were carried out in 2001-2002. The samples were collected by different methods of gillnet, beach seine, castnet, electroshocker and dipnet. After catching the fishes, they were transfered to the laboratory for further species indentification. A total of 1639 specimens were collected that belong to 7 orders, 9 families, 15 species and subspecies. The identification orders were: Cypriniformes, Salmoniformes, Syngnathiformes, Cyprinodontoformes, Siluriformes, Perciformes and Gasterosteiformes. Among different orders, the order of Cypriniformes and Gasterosteiformes and among different families, the Cyprinidae and Cobitidae and among different species, Perca jluviatilis and Scardinius erythrophthalmus had the most and the least abundance, respectively. The stock of Tinca tina and Esox lucius were so high. It should be noticed that three species of Cyprinus carpio, Scardinius erythrophthalmus and Cobitis taenia were found for the first time in this wetland

Bacterioplankton of Anzali Lagoon (quantitative survey)

The quantitative survey of bacterioplankton in Anzali Lagoon water (50 stations) was accomplished in a few month period with attention to physical, chemical and biological specifications, so as to be able to use the results as the indicator for trophic quality assessment of the lagoon. During the measurement the average number of the bacterioplankton in the lagoon was 5.76 million/cm3 and the alteration range in different areas was between 4_10 and 7.69 million 1 cm3. The areas containing much planktonic and macrophytic plants or more organic compounds, had more abundant bacterioplankton. The obtained values for the bacterioplankton in this study is specifically for abundant hydrological ecosystems, and the number of the bacterioplankton shows the eutrophy of the Anzali Lagoon in compare with hydrological environments of the other districts, especially the temperate districts

An investigation on digestive parasites of fishes in Boojagh Wetland, north Iran

Digestive parasites of commercial fish species in the Boojagh wetland were studied in 2002. The fish species included Esox lucius, Cyprinus carpio, Blicca bjoerkna, Tinca tinca, Carassius auratus, Rutilus frisii kutum, Rutilus rutilus and Scardinius erythrophtalmus. Species C. auratus, R. frisii kutum and B. bjoerkna were found free of digestive parasites. The other five species were carrying one of the three digestive parasites Raphidascaris aces, Caryophyllaeus fimbericeps and Asymphylodora tincae. R.acus parasite was isolated from E. lucius and E. erythrophtalmus infecting the species with a mean intensity of 1.1± 11.15 and 1.8±0.83, a prevalence of 15.4% and 20.2% and a mean abundance of 1.69 and 0.38 respectively. C. carpio and R. rutilus were only infected with C. fimbericeps parasite with a mean intensity of 30.30±46.33 and 5±0, a prevalence of 46.5% and 2.78%, and a mean abundance of 15.48 and 0.14 respectively. The parasite A. tincae was observed only in T. tinca infesting the fish with a mean intensity of 20±0, a prevalence of 25% and mean abundance of 5. Infection of Esox lucius with the parasite A. tincae had been reported from other sites, but this is the first record of Scardinius erythrophtalmus being infected with the parasite. This is also the case for infection of C. carpio with the parasite Caryophyllaeus fimbericeps which was reported before, but found infesting R. rutilus in the Boojagh wetland for the first time

Feeding behaviour of Perca fluviatilis in Amirkelayeh lagoon

The diet survey of Perca fluviatilis of Arnirkelayeh lagoon was carried out during four seasons of 2001. After collecting the fish samples by different fishing gear such as gillnet, seine, castnet and dipnet, fishes were measured and diet was studied. Also according to this research from 143 specimen, fishes were in the age range of 1+- 6+, total length of 9.5-33.5 cm (T.L= 19.83±4.46 cm) and weight of 10.5 - 350 g (Mean weight of 114.45±77.55g). According to obtained results, the relative lenght gut was 0.58±0.09, index of fullness was 129.5±257.4, fullton's condition factor was 1320.7±534.1 and vacuity index was 7.69%. Perca jluviatilis was fed from 18 kinds of food with respect of frequency were: water bug, Odonata, Gammarus, plant materials, Chironomids, Tinca tinca, Hemiptera, Perca fluviatilis, Snail, Syngnathus abaster, Gambusia holbrooki, Pungitius platygaster, diptera, branchiopoda, trichoptera, tubifex, frog and shrimp. By consideration of composition eaten foods and their frequency percentage in Amirkelayeh lagoon Perca fluviatilis, it can be concluded that this fish is an omnivorous and cannibalism species. Also, feeding habit of Perca fluviatilis changes according to age, season and sex

Determination of maximum allowable concentration and LC50 96h of Sefidroud River sediments for Persian sturgeon (Acipenser persicus) fingerlings

The impact of Sefidroud River sediments on the fingerlings of Persian Sturgeon (Acipenser persicus) was studied in 2005. The tests were done in 20 liter aquariums each containing 10 Persian Sturgeons fingerlings weighing 3-5 grams each. We devised 6 treatments and a control with 3 repetitions in the four day investigation through which the lethal concentration (LC50 96h) of Sefidroud sediments were studied. During the test, physicochemical parameters of water such as pH, oxygen and temperature were measured as 8, 8.5mg/1 and 25±1°C respectively. The results showed that LC5096h and LC50 24h of sediments on Persian sturgeon were 15367.39mg/1 and 124882.04mg/1 respectively. We determined the maximum allow-able concentration (M.A.C) of sediments to be I 536.74mg/l

An investigation on fish infection with Diplostomum spathaceum in Amirkalayeh Wetland

Infection with Diplostomum spathaceum parasite is studied in 660 fish specimens from Amirkalaieh wetland of Guilan Province. We collected samples of fish belonging to Esax litchis (78 pieces), Percalluviatilis (163 pieces), Tinca tinca (105 pieces), Cilurtts glanis (64 pieces), Carasshis ouratus 64 pieces, Bliccia bjuericlia (95 pieces) and Rutilus rutilus (91 pieces) since spring to winter 2001. We found the highest infection rate in Rutilus rutihis (63.33%) while the lowest was seen in gialiis (3.13%). The highest and lowest average infection severity were detected in Rutilus rutilus (13.49±10.82), and Tinca tinca .2±0.45), respectively. The highest parasite abundance was related to Rutilus rutihts (7.04±0.93), and the lowest abundance was observed in Tinca tinca (0.06±0.27). Parasite count range was most in Rutilus rutilus (1-49), and least in Tinca tinca (1-2). Statistical analyses revealed significant differences in species, age, sex and season as related to the infection with the parasite

Determination of LC_(50) 96h of dyazinon, hinosan and tilt for Acipenser nudiventris fingerlings

The toxic effects of agricultural pesticides Dyazinon, Hinosan and Tilt (Propiconazole) were studied on Acipenser nudiventris fingerlings (1-3g) in Spring 2005. We conducted our experiments in aquaria holding 20L water in static systems based on O.E.C.D method using five treatments, one control concentration and three replications. In each aquarium, ten individual Ship Sturgeon fingerlings were introduced, and water physical and chemical factors were controlled to be in the range pH=7-8, TH>400mg/l (CaCO _(3)) as for the water used for culture, and DO=80% and temperature was kept between 24 ±1°C. Our results for the LC _(50) value of Dyazinon, Hinosan and Tilt in 96 hours were 0.36, 0.28 and 3.9mg/l in the fish fingerlings. We also determined the maximum allowable concentration value of the toxins at 0.036, 0.028 and 0.39, respectively

A survey on lethal concentration of Cu and Pb in Caspian Sea Kutum (Rutilus frisii kutum)

The Guilan province in the north of Iran has witnessed a rapid industrial development in recent years causing pollution of water resources in rivers, wetlands and the Caspian Sea coastal areas. We studied the acute toxicity of Copper and Lead in kutum fingerlings through acute toxicity and M.A.C value determination in summer and autumn 2006. A total of 21 aquariums with a capacity of 30 liters each stocked with 10 fingerlings were used in our experiments with the two metals. Six aquaria and six concentrations of Cu and Pb composed the 18 treatments while 3 other aquaria were used as control. For each treatment, three replications were conducted. The relevant physical and chemical parameters of water during the experiments were measured including pH which was in the range 7-7.5, DH=200-250mg/l (CaCO _3), DO= 80% and temperature which was recorded as 24 plus or minus 1°C. Fish investigations were conducted in 24 hour intervals. The results indicated that the lethal concentration (LC sub(50)96h) for Copper and Lead are 1.92mg/l and 252.12mg/l respectively and M.A.C. value for Copper and Lead are 0.192mg/l and 25.212mg/l respectively in the Caspian Sea kutum. Hence, we conclude that Copper is more toxic than Lead for the fish

Comparison of morphometric and meristic attributes of bream (Abramis brama orientalis), in Caspian Sea and Aras Dam Reservoir

Morphometric and meristic specifications of Abramis brama orientalis of the Caspian Sea and Aras Dam Reservoir was studied in the year 2002. For this purpose, 40 morphometric attributes, 16 meristic attributes and 37 specifications in relation to the proportions of speciality of morphometric attributes of the Abramis brama orientalis were evaluated from the two habitats. Anova, factor and discriminant function analyses were conducted on the data. According to results the average coefficient of variation in morphometric, meristic and proportion of speciality of morphometric attributes for Abramis brama orientalis of Caspian Sea was 22.85, 3.24 and 7.68 and for Abramis brama orientalis of Aras Dam Reservoir was 17.45, 3.53 and 15.27. The Abramis brama orientalis of the two areas showed meaningful differences in 35 morphometric factors, 6 meristic factors and 25 factor of proportion of the speciality of the age had significand differences (P<O.05). Factor analysis showed that the Abramis brama orientalis of the two habitats had 80.62% of changes in 7 factors of first morphometric attributes, 73.65% of changes in the 9 factors of the first proportion of morphometric specialities and 46.52% of changes in the 4 factors of the first meristic attribute. We showed that, fork length, standard length, proportion of head length to the standard length, number of scales of the lateral line, number of scales under the lateral line, number of scales above the lateral line, radius of dorsal fin and number of dorsal fins can be used to separate population of the fish from the two habitats. The first two factors of proportion of speciality of morphometric and meristic attributes causes total separation of the two populations. We found different in morphometric specialities between the two specialities of morphometric and meristic attributes. It is suggested that different environmental conditions have led to the differences in the populations of the fish in the Caspian Sea and Aras Dam Reservoir