Aquatic Ecology
Year:2017 | Volume:7 | Issue:1 |Papers Count:15

This study was conducted to identify the intertidal crab species and their temporal distribution caught by set net in northwest of the Qeshm Island. A total of 120 crabs were collected monthly from February 2015 to January 2016. The specimens were collected by hand and then fixed in formaldehyde 10%, transported to the laboratory and then identified based on their morphological characteristics using identification keys. The results showed that the specimens belong to 3 families including Portunidae, Macrophthalmidae and Pilumnidae. Portunus segnis and Venitus dentipes were dominant species in set net in northwest of the Qeshm Island whereas, Eurycarcinus orientaliswas observed in some months in the study period. Temporal distribution and frequency of species was different in overall year, so that the frequency of crabs in warm seasons (spring and summer) was higher than than in cold season (winter).

The study was conducted to obtain some information about temporal and spatial variations of multifilament drift gillnet catch communities in coastal waters of Hormozgan Province (Persian Gulf) from October to March 2014. Totally, seven families were identified including Scombridae, Carangidae, Carcharhinidae, Sphyranidae, Stromatidae, Belonidae, and Pesttodidae with total biomass of 73. 03%, 12. 67%, 7. 88%, 1. 36%, 0. 73%, 2. 24% and 2. 06%, respectively. Kawakawa (Euthynnus affinis) showed the highest percentage of total catch with the number and weight percentage of 33. 26% and 27. 9% respectively. The lowest percentage catch was Indian spiny turbot (Psettodes erumei) with 7% and Frigate tuna (Auxis thazard) with 5% of total catch. Simper analysis between autumn and winter showed that the species Kawakawa (E. affinis), Talang queen fish (Scomberoides commersonnianus), Indian mackerel (Rastrelliger kanagurta), Long tail tuna (Thunnus tonggol), Frigate tuna (Auxis thazard) and Silver pomfret (Pampus argenteus) were responsible for 81. 67% of dissimilarity. Two species Kawakawa and Talang queen fish showed the highest dissimilarity.

This study aimed to investigate the fatty acid composition of zooplankton and common carp larvae in hatcheries at the first seven days of larval rearing. SFA was higher in rotifers before releasing of larvae on = day 1 gain (6. 15%), compared to that of day 7, and significantly decreased in the rate of 3. 53%. On day 7, total amount of MUFA was increased significantly. Oleic acid was the most dominant monounsaturated fatty acid in all treatments except day 1 and showed the higher amount day 5. . The highest PUFA concentration was on day 7 with 52. 27% and the lowest level was on day 4 with 42. 92. The rotifer PUFA was significantly lower in that that of larvae before releasing. At the end of the experiment, total amount of PUFA increased of in the rate of 5. 16%. The amount of omega 6, linoleic acid, arachidonic acid and acid was higher in the body of larvae compared to rotifer. However their values were increased at the end of the experiment. The levels of EPA and DHA were higher in rotifers compared to those in fish larvae on day before the larval releasing. The results of this study indicated that rotifer is a rich source of fatty acids for food for developing fish larvae. MUFA levels was lower in rotifer than the larvae. Similar to SFA, MUFA levels decreased significantly in the rate of 1. 79% from day 1 to day 7.

The rivers are under threat by numerous pollutions and their quality assessment is a need. Water quality of the Gamasiab River in Kermanshah Province was assessed using biological indices (BMWP and ASPT method). Six stations were selected and macro invertebrates were collected by surber sampler from July 2013 to May 2014. In this study, 11 families of the macro invertebrates from 10 orders were identified; Gammaridae، Lymnaeidae and Chironomidae were the most dominant, respectively. After identifying and counting the macro invertebrates, ASPT and BMWP indices were calculated to determine the contamination of Gamasiab River. BMWP mean showed significant differences between all stations and stages (P < 0. 05). Except for station 6 that was in very good class, the water quality of the Gamasiab River was classified as middle to bad condition. ASPT mean showed significant differences between stations (P < 0. 01) and classified the water quality of Gamasiab River in the category 4. According to the results, environmental and ecological characteristics of Gamasiab River are moderate.

Penaeus vanamei is one of the most important penaeide shrimp species in Persian Gulf. This research was carried out to determine the genetic status of broodstocks of this species by sequencing the cytochrome oxidase I gene (COI). Sampling was performed from two hatcheries in hormozgan province (Kolahi and Tiab) and a hatchery in Bushehr province (Delvar). Seven haplotypes were identified from 502 aligned sequences. Phylogeny study showed that all specimens from the three studied hatcheries were in a main clade with two clusters showing highly Homosigisity of Bushehr and Hormozgan hatcheries. On the other hand, three haplotypes BU. A3, A4, A6 derived from Bushehr area were distinguished from the other haplotypes of Bushehr and Hormozgan regions, showing that the heterozygosity rate in the broodstocks of Bushehr area is much higher than Hormozgan area. The haplotypic status of the COI gene indicates high homozygosity levels among imported broodstocks in hormozgan that can lead to increase in the amount of blood coefficient between broodstocks and decrease in growth and survival rate among postlarves in near future.

Resistant of pathogens to common antibiotics is a major global problem, and efforts discover new antibiotics from less known resources, is an inevitable. Native sponges of Persian Gulf have high potential in the field of medical biology, but have received little attention. In this study, actinomycetes that capable to produce anti-bacterial metabolites isolated and examined. Two sponges of Persian Gulf Haliclona simulans and Dictyonella sp. were collected with scuba diving in the waters around the Kharku Island and mesohyle of sponges were used to obtained actinomycetes. A Primary screening was carried out to identify antibiotic producing strains by cross streak method. Chloroform and methanol extracts obtained from active strains and their impacts against pathogens were examined by disk diffusion method. Moreover, the most active actinomycete was identified by molecular method. Among 12 actinomycetes obtained in primary screening, 7 isolates had the ability to inhibit growth of pathogenic microorganisms and mz7 had the most and mz3 and mz5 had the least inhibition activities. In the disk diffusion test, methanol extract of mz1 and chloroform extract of mz7 displayed the highest anti-bacterial activity. Molecular method showed that isolated mz7 had 97% similarity to Micrococcus yannanensis strain YIM 65004. According to significant anti-bacterial properties of identified strains in this study, it seems that there is potential to do further investigation in this context.

This study evaluated the possibility of VNN occurrence and the effects of Chlorella vulgaris on immune parameters before and after exposure to Viral Nervous Necrosis virus in Caspian Sea salmon (Salmo trutta caspius). Fish were divided into 4 treatments with three replicates. Treatments included one control group and three experimental groups (T1, T2 and T3). Fish in control group, T1, T2 and T3 were fed by diet supplemented with 0, 1×108, 2×107 and 3×106 Cell/ml chlorella/450 g food respectively, for 8 weeks. Blood samples were collected to calculate immune parameters (IgM, C3, C4, Total protein, respiratory burst, Albumin and Lysozyme). In addition, NNV supernatant was used for virus challenge in Caspian Sea in all treatments. Fish were monitored for 14 days to examine the supernatant pathogenesis and measure the changes in immune parameters after challenge with virus. RT-PCR, nested-PCR, IFAT, IHC tests, cell culture and histopathology examinations were also carried out. Results showed that S. trutta caspius fingerlings were resistant against NNV, so that no virus was observed in fish brain and eye tissues in all treatments. Moreover, Ch. vulgaris stimulated the immune system of S. trutta caspius probably due to the compositions such as carotenoid pigment and different kind of vitamins in this microalga.

One of the most important issues in environmental management of coastal waters is the evaluation of Eutrophication. In this study, the trophic status of coastal waters of Hormozgan province was evaluated using Scale (TRIXCS) and Unscale (UNTRIXCS) trophic indices in 2012. The results showed that TRIXCS values were in the range of 3. 6 to 5. 9 (in the area 1 Mezo-Eutroph, areas 2 and 3 Mezotroph, and area 4 Oligo – Mezotroph) and UNTRIXCS values ranged from 3. 4 to 5. 8 (no risk in the 4th area and high risk in other areas). Based on the results of TQR trix index, the status of eutrophication in areas 1, 2 and 3 was in good status, while area 4 was in very good status. The coefficient efficiency trophy index was 4. 92± 0. 03, suggesting that the amount of nutrients consumed by phytoplankton near shore of Bandar Abbas (in area 1) was higher than other areas. Altogether, according to comments and suggestions by many scientists, trophic state Scale (Trixcs) index can be used for evaluation of eutrophication in coastal waters, after revisiting and development.

This study aimed to achieve length frequency, condition factor and length-weight relationship of the rock oyster, Saccostrea cucullata in the coastal waters of Persian Gulf. Sampling was carried out by 0. 25 m2 quadrat through intertidal zone from winter 2015 to autumn 2016. According to the results, length-weight relationship calculated as W=0. 000004L2. 79 for both sexes. In addition, coefficient of determination (R2) value was determined as 0. 94. Furthermore, b value was significantly different from 3. Condition factor was estimated as 14. 36, 16. 87, 20. 85 and 20. 76 for autumn, winter, spring and summer, respectively. Mean length and weight were 34. 4± 4. 96, 36. 8± 8. 46, 30. 25± 7. 1 and 33. 31± 4. 31 cm and 8. 9± 7. 57, 10. 4± 9. 8, 10. 9± 6. 11 and 7. 8± 4. 19 g in spring, summer, autumn and winter, respectively. Maximum and minimum length were 97mm and 2 mm in spring and autumn, respectively. Maximum dry weight was found in winter (2. 21g) and the minimum was determined in autumn (0. 009 g). Maximum length frequency was observed in the 35-45 mm range class in all seasons. However, range class of 40-45 mm was also frequent in the spring. According to the nMDS results based on length and weight ordination, autumn was distinct from all seasons probably due to the juvenile recruitments in this season.

This study was carried out to investigate the phytoplankton composition in Gorgan Bay. Water samples were collected from 11 selected sites in Golestan bay, monthly from March to February. Thirty five genus were identified among which Bacillariophyta was the dominate group with 17 genus, while the Euglenophyta had the minimum. Abundance and biomass of phytoplankton showed spatial and temporal variations in the Bay. After Bacillariophyta, Cyanophyta was the most dominant group in spring, summer and autumn, while the Pyrrophyta was the most dominant in winter. Moreover, the highest number were counted for Nitzschia sp and Gyrosigma sp in spring, Gyrosigma sp, Euglena sp and Anabaenopsis sp in summer, Anabaenopsis sp and Prorcentrum sp in autumn, and Cheatoceros sp and Cyclotella sp in winter. Maximum abundance and biomass were calculated for site 8 (near Khozeini Channel) and the minimum were in sites 1 and 3 (central part of the bay) respectively. The average values of Margalef, Simpson and Shannon-Wiener indices were 0. 3± 0. 27, 0. 37± 0. 25 and 1. 22± 0. 75 respectively, indicating low diversity in Gorgan Bay. The maximum Margalef (0. 99), Shannon-Wiener (2. 77) and the minimum Simpson (0. 07) indices were calculated in February. Results of RDA showed that water temperature, water depth, transparency, phosphate, nitrate, pH, total alkalinity and dissolved oxygen had significant, high correlation with abundances of different phytoplankton genus.

In this study, species composition, density and biomass of zooplanktons including Rotatoria, Protozoa and Meroplanktons were sampled using Juday net with mesh size of 100 µ at depths of 5, 10 and 20 meters in southern Caspian Sea (Babolsar) in two seasons of cold (Feb. 2015) and warm (June 2015). This study identified Asplanchna sp. and Synchaeta sp. from Rotatoria, and Balanus sp., Pelecypoda larvae, Balanus cypris and Nereis sp. larvae from Meroplankton. Globogeria sp. was the only protozoa observed in this study. Two way ANOVA analysis showed that sampling site and season had significant effect on density and biomass of zooplankton (P<0. 05). Duncan's multiple range test showed that the density and biomass of zooplankton groups were significantly higher in the station A1 than two other stations (P<0. 05). Moreover, the density and biomass of zooplankton were significantly higher in cold season compared to those of warm season (P<0. 05). The highest density and biomass belonged to Asplanchna sp. from Rotatoria in the cold season with the density of 23381. 47± 2907. 94 org. m-3and the biomass of 476. 6± 58. 2 mg. m-3. The highest density and biomass of zooplankton was observed at the depth of 5 meter, and density and biomass were decreased by increasing the depth. According to the results of this study, species composition, density and biomass of zooplanktons including Rotatoria, Protozoa and Meroplanktons were very low in the south of the Caspian Sea (Babolsar).

The estimation of fish potential production and trophic status are two important and necessary parts of fisheries management in lakes. This study was conducted to determinate the trophic status and fish production potential of Golbolagh Lake, for one year from October 2013 to September 2014. Physicochemical parameters and other necessary data such as chlorophyll a, phytoplankton phylum dominance and macrobenthos biomass were used to estimate the fish potential production and trophic status of Golbolagh Lake. Trophy State models of Carlson, total nitrogen model of Kratzer and Brezonik and table of Li and Mathias were used to determine trophic status of Golbolagh Lake. The fish potential production of Golbolagh Lake were estimated using Ryder (MEI) model, Janjua, De Silva and Funge-Smith, Li and Mathias and Dawning et al. models. The results showed that Golbolagh Lake is a eutrophic to hypertrophic lake and annual average of fish productivity was estimated 138. 42± 72/13 (Kg/ha). Owing to high trophic status of Golbolagh Lake, fish production was expected to be greater. However, due to low density of phytoplankton, production was medium.

Many of the mangrove forests are characterized by macroalgae growing epiphytically on pneumatophores, prop roots, stems and other hard substrates. Mangrove macroalgae have an important role as primary producers in the estuarine ecosystem. In the present study, four different mangrove habitats were selected to identify the macroalgae inhabiting the roots of a mangrove species Avicennia marina in the Iranian coastlines of Persian Gulf. Field observations identified no epiphytic macroalgae on the roots of A. marina. Previous studies show that mangrove maroalgae exist only in the estuary habitats with fresh water entrance. Therefore, the absence of macroalgae on Iran's mangrove forests is likely due to high salinity in these areas. Moreover, the possibility of chemical defense and allelopathic reactions of mangroves can be investigated.

The mechanism of compensatory growth in rainbow trout (Oncorhynchus mykiss) was studied in a completely randomized design with four experimental treatments and a control group (no food deprivation) with three replicates. Animals in treatments 1 to 4 were fed with rates of 0, 25, 50 and 75% saturation, respectively for two weeks. Then, the treatments were fed twice a day until saturation level for more three weeks. The results of growth indexes, chemical body composition and blood factors showed that rainbow trout could tolerate compensatory growth and feeding until 25% of saturation level.

The aim of this study was to evaluate the safety effects of prebiotic isomalto-oligosaccharid on the damage of liver and gill tissues in common carp exposed to lethal concentrations of toxin butachlor. A total of 120 specimens of common carp with an average weight of 6. 13± 0. 31 g were kept. Water physicochemical parameters were measured during the experiment. LC50 96h for toxin butachlor was obtained 0. 785 on the basis of four lethal concentrations of 1. 05ppm, 1. 1ppm, 1. 2ppm and 1. 15ppm, each with three replications. The highest and widest complications were observed in primary and secondary blade gill including hyperplasia, necrosis, secondary blade attachment, destruction of secondary lamellae and secondary lamellae was bent. In liver complication of hemorrhage, necrosis, the destruction of liver cells were observed. This study showed that prebiotic isomalto-oligosaccharid can reduce the damage of liver and gill tissues in exposure to lethal concentrations of butachlor poison.