Iranian Scientific Fisheries Journal
Year:2010 | Volume:19 | Issue:3|Papers Count:20

This study was conducted to investigate the effects of rotifers enriched with betaine and concentrated diet containing betaine on growth performance, survival and resistance to salinity (10 and 50ppt), temperature (42oC) and formalin (100ppm) stresses in Indian white prawn (Fenneropenaeus indicus) post-larvae.A complete randomized design with three replicates per treatment in nine 20-1 tanks was chosen. Treatments were: Artemia nauplii, rotifers and concentrated diet (control); Artemia nauplii, rotifers enriched with betaine and concentrated diet (treatment 1) and Artemia nauplii, rotifers enriched with betaine and concentrated diet containing betaine (0.8%) (treatment 2). The larvae were fed 6 times per day at 4h intervals. There were significant differences in growth and survival rate between the treatments containing betaine (treatment 1 and 2) and control treatment (P<0.05). Furthermore, the larvae that were fed with betaine (treatment 1 and 2) had significantly higher survival rate in stress resistance testes (P<0.05). The present study showed that betaine has positive effect on growth performance, survival rate and resistance to stresses in Indian white prawn.

This study provides information on the effect of three light intensities (37.5, 62.5 and 100 mmol photons.m-2 S-1) and photoperiods (light: dark) cycle 8:16, 12:12 and 16:8h ongrowth rate, duplication time and biomass production in microalga Chlorella vulgaris. Stock of C. vulgaris was separated from water samples taken at Anzali Wetland, purified and cultured in 1000ml Erlenmeyer at constant temperature 25±0.5oC, using Zehnder medium. Cell count was conducted daily and biomass was measured at the exponential growth phase in different treatments. Analysis of variance indicated significant difference (P<0.05) among light regimes. The maximum growth rate 1.13d-1 was observed at 100mmol photons. M-2 S-1 and 16:8h light duration and also the minimum duplication time 0.61d-1 occurred at this treatment. The maximum biomass 2.05gl-1 was recorded at 62.5mmol photons.m-2 S -1 and8: 16h light period.

Central and western coastal waters of the Persian Gulf along Hormuzgan province were investigated for site selection of artificial reefs installation. The grain size and organic carbon content of sediments were studied seasonally in the year 2007. For sampling, we stratified the area between the south of Qeshm Island to Hendorabi Island to 10 transects, and partitioned each to 3 sub-transects (Coastal line to 10, 10-20 and 20-30m deep), using a random design.The maximum and minimum amount of silt were recorded in transects of Bandar Haseineh and Bandar Chiroyeah (45.39% and 38.79%), for sand transects of Bandar Masen and Bandar Haseineh showed the maximum and minimum (63.95% and 38.79%) and for clay transects of Bahman Jetty and Bandar Masen (23.47% and 9.02%) were recorded and the highest and lowest respectively. Also, the maximum and minimum amount of carbon organic content was determined in Bandar Kong transect (1.62%) and Hengum Island transect (0.63%), respectively. The results of one-way analysis of variance showed a significant difference in organic carbon content of sediments from transects of Hengum Island, Bandar Masen and Bandar Gourzeh in comparison with other transects (P<0.05), (95% confidence interval).However, the difference was not significant for grain size and organic carbon of bottom sediments in all stations (P>0.05). Also, we found a significant correlation between silt (r=0.52), sand (r=-0.63) and clay (r=0.67) with organic carbon (P<0.01). Finally, the best transects for artificial reefs installation were defined based on bottom hardness (Hengum Island, Bandar Masen, Bandar Selakh and Bandar Chiroyeah), productivity (Hengum Island, Bandar Masen, Bandar Selakh, Bandar Bostaneh, Bandar Haseineh, Bandar Charak and Bandar Gourzeh) and organic carbon (Bahman Jetty, Bandar Selakh, Bandar Kong, Bandar Bostaneh, Bandar Haseineh and Bandar Charak).

We assessed the effects of Artemia urmiana nauplii as fish food enriched with different oils on growth and survival rate of Persian sturgeon (Acipenser persicus) larvae. Sturgeon ovary oil, cod liver oil, linseed oil and a commercial emulsion (ICES, Belgium Brand) in three levels (100, 200 and 300ppm) for two periods of 12 and 24h were used for enrichment of A. urmiana nauplii fed to Persian sturgeon larvae during 20 days. Length, weight, SGR, CF, FCR and biochemical analyses including fatty acid profiles, total lipid and protein were measured for sturgeon larvae. Maximum length (43.9±2.3mm), OW (34.9±8.7mg), and minimum FCR (1.15±0.21) for sturgeon treatment 12h-200ppm, maximum SGR (13.4±0.6) for sturgeon treatment 12h-300ppm, CF (0.47±0.03) for linseed treatment 12h-300ppm and ICES 12h-300ppm (0.47±0.05), survival (94.1±0.2%) for ICES 24h-200ppm, protein content (70.05%) for ICES 12h-200ppm, lipid (21.14%) for sturgeon ovary oil treatment 24h- 300ppm, Arachidonic acid (ARA) (1.54±0.22mg.g OW) for cod liver oil treatment 24h- 300ppm, EPA (3.53±0.36mg.g OW) for cod liver oil 24h-100ppm, and OHA (3.22±0.09mg.g OW) for ICES and linseed treatments 24h-200ppm were obtained. OHA/EPA ratio in sturgeon larvae before active feeding was 1.75 which showed no significant difference compared to ICES in two levels (24h-100 and 200ppm) and linseed in two levels (24h-100 and 200ppm). ANOV A of different treatments showed significant differences between length, CF, survival rate, total lipid, ARA, EPA, and OHA contents of the sturgeon larvae among treatments (P<0.05).

Artemia nauplii and rotifier are considered as the most important live food in aquaculture because of their high nutritional quality, suitable size and mobility. The survival rate and resistance of white shrimp (Litopenaus vannamei) postlarvae fed by Artemia urmiana, Brachinus plicatilisand concentrated food were investigated. Larvae at the stage of Protozoae 1were stocked in 14 liters plastic containers filled by 6 liters of water. There were 75 larvae per liter in each container. The larvae were fed in 3 treatments: T1 (rotifier), T2 (Artemia) and T3 (concentrated food). Each treatment was repeated 3 times and used during Protozoae 1 (PL1) to Post-larvae 5 (PL5) stages. Data analysis was done through Duncan Test. We observed that from Mysis 1 stage to PL1 the rotifier can be used for shrimp feeding and from this stage to PL5, Artemia nauplii can be used as food for the larvae. To evaluate the quality of larvae, the physiological resistance tests were conducted against formalin and salinity in different periods of time (30, 60 and 90 minutes). We found that at the PL1 stage, the maximum survival (100%) in formalin tests (100ppm) and (200ppm) and salinity test (15ppt) was related to feeding the shrimp larvae with rotifier. However, at the PLs stage, the maximumsurvival (100%) under the same conditions was related to application of Artemia nauplii food. The concentrated food showed the minimum survival in all tests.

This study was carried out to investigate heavy metals concentration in the sediments ofLifeh and Busaf coastal waters. Four stations in the Khore-Mussa western coasts were sampled seasonally from winter 2006 to autumn 2007. Concentration of Hg was measured using Voltammeter and other metals were analyzed using Polarography method.The mean concentrations were 68.8 for Zn, 23.5 for Pb, 21.8 for Cu, 12.8 for Co, 2.14 for Cd, 73.6 for Ni and 0.19 for Hg in mg/kg. According to the concentration results we ranked theheavy metals as: Ni > Zn > Pb > Cu > Co > Cd > Hg. Based on Muller geochemical index (Igeo), sediment quality for Pb and Hg is in class II (moderately polluted) and for other metals is in class 0 (unpolluted). The similarity between stations and different parameters were demonstrated using PCA and Clustering analyses.Although significant differences were not observed between the studied stations, but PCA analysis of heavy metals concentrations showed some similarity and differences between them. These similarities might be linked to geochemical characters of sediments and the nature of water currents in the study area.

This project was carried out to increase shelf life of kilka and prevent color changes during cold storage. Edible film made by sodium alginate (0.5% concentration) was used for fish packaging at time zero. The covered samples were kept at -18oC. Examinations were carried out for a period of six months. Coliform, Escherichia coli and Pseudomonas bacteria contamination were negative until the end of storage period in the covered samples. Total bacterial counts and Acetaphylococcus bacteria count were lower in the treated samples (2.93 and 1.4610g cfu/g, respectively) compared with the control specimens (3.21 and 2.2810g cfu/g, respectively). Chemical factors consisting of humidity, protein, lipid, ash and calorie were higher in the treated samples (73.34%, 18.96%, 4.62%, 2.88% and 134. 63% kcal/kg, respectively) compared with the control samples (59.43%, 18.04%, 4.03%, 2.87% and 108.43% kcal/kg, respectively) and fresh fish samples (73.93%, 18.91%, 4.59%, 2.87% and 117.28% kcal/kg, respectively). Free fatty acids (0.77 and 9.21g/100), thiobarbitoric acid (0.001 and 0.15mg/kg), peroxide value (0.06 and 3.75meq/kg oil), TVN (6.92 and 16.28mg/100g) and pH (6.34 and 6.91) were lower in the treated samples compared with the control samples. However, no statistically significant decreases were observed in chemical factors including moisture, peroxide value, TVN and pH in the covered samples compared with the control samples during cold storage (P>0.05). According to the statistical analyses of sensory specifications including taste, odor, color, tissue and total acceptance, there was a significant difference between the covered samples and the control ones (P<0.05). Using the results of bacterial, chemical and sensory tests and statistical analyses, the covered samples had a favorable quality until the end of storage period. Also, based on the results of sensory analyses and moisture test, the control samples had a favorable quality for a period of three months.

Total Metallothionein (MT) biosynthesis and Mercury bioaccumulation under control& acute Mercury exposure were investigated in Scat (Scatophagus argus). Tissues from liver and gill of samples Scats were exposed to different Mercury concentrations (10, 20, 30mg/l) for 24, 48, 72 hours. Mercury contents were determined through Cold Vapour Atomic Absorption Spectrometry (CV AAS). Total MT levels were determined by Enzyme-linked Immunosorbent Assay (ELISA) method. Induction of MT during exposure was tissue specific, displaying different response patterns in gill and liver. Mercury accumulated in liver much stronger than gill and the latter also showed lower MT level. Although after exposure to different mercury concentration during different periods, MT biosynthesis in liver showed a significant increase (P<0.05) but in gill did not significantly modify total MT except for 72h exposure at 30mg/l. Nonetheless, the relationship between MT biosynthesis and Mercury bioaccumulation in both tissues was significant. The results suggest that this form of MT presence in S. argus was Hg-inducible and could be extended as a biomarker of Mercury pollution in marine ecosystems and especially in Persian Gulf.

Using reference books, monitoring buyers' behavior and interviewing the experts, the effective parameters on home consumption behavior of farmed fish were identified and compiled as a questionnaire. After the reliability and viability evaluation the questionnaire was filled randomly in the spring of 2008 for 295 households of different localities in Tehran. The allocation of questionnaires was conducted based on the proportion of population in each locality. The degree of importance of effective parameters and their priority were calculated by Friedman test. The results showed that, quality, taste, smell and protein content of grocery basket are the most important purchasing factors among Tehrani households. However, those who use only farmed fish or those who do not use fish at all, after quality, smell has the highest importance, and in the fourth priority, instead of protein content of grocery basket, fish bone has higher effect. We suggest that to improve consumption of farmed fish, apart from quality, the strategies of deodorizing, taste improvement and decreasing fish bones, shall be taken into consideration during harvest, transport and fish processing.

Water hardness and turbidity are important parameters in zooplankton culture, especially for Cladoceran affecting growth and reproductive parameters of the plankton. Effects of water hardness and turbidity on growth and fecundity of the Cladoceran, Moina macrocopa, was investigated by culturing and feeding them on green algae Scenedesmus quadricauda. Experimental treatments for hardness were 0, 20, 40 and 80mg/1 as CaCO3 and for turbidity were 0, 20, 40 and 80 NTU (Nephelometric Turbidity Unit). Experiments were carried out in 500ml flasks with initial density of 15 individuals per flask in randomized complete block design with three replicates. After 10 days, we found that M macrocopa, had the maximum population density (370.5-365.0 individuals per flask), maximum specific growth rate (SGR) (0.35/day), and the shortest population doubling time (Dt) (1.98 days) at 0 and 20mg/1 CaCO3, all with significant differences compared to other treatments (P<0.05). In contrast, we observed the maximum population density (296-325.5 individuals per flask) at turbidities of 0 and 20 NTU, maximum SGR (0.33/day) and the shortest Dt (2.10 days) at turbidity of o NTU, with significant differences compared to other treatments (P<0.05). The highest fecundity of M macrocopa was obtained at 20mg/1 as CaCO3 and turbidity of 0 NTU which significantly differed with other treatments (P<0.05). Overall, we showed that M macrocopa in freshwater with hardness less than 20mg/1 as CaCO3 and turbidity less than 20 NTU had better growth and fecundityperformance. The species can be used to evaluate habitats where water hardness and turbidity ishigher. Mass culture of the species based on its growth and reproduction under these optimal conditions could provide suitable zoo planktonic biomass for feeding of fish larvae.

This study was conducted to determine morphometric and meristic characteristics of Garrarufa in 13 stations of Tigris and Persian Gulf basins. We caught 310 specimens during the year 2007-2008 using electro-shocker and sachok. Univari ate analysis of vanance (ANOV A) and principal component analysis were conducted and the ANOV A revealed significant differences in 28 morphometric and 9 meristic factors (P<0.05). Factor analysis showed that G. rufa of thirteen stations had 48.855% changes in 3 factors of the first morphometric characters (pectoral fin length, ventral fin length, depth of anal fin) and 71/611% changes in 3 factors of the first meristic characters (lateral line scales, circum peduncle scales, predorsal scales). Plotting the first and second principal component morphometric and meristic characters showed that the Mond River population was separated from the others but the other populations were overlapping with each other in the characteristics studied.

The molecular structure in populations of Mnemiopsis leidyi were examined for 200 samples from the south (Guilan, Mazandaran and Golestan provinces) and north of the Caspian Sea. DNA was extracted from M leiydi tissue by phenol-chlorophorm method and its concentration was found at 50 to 100ng. We used the PCR method using 19 random primers (10bp). The PCR products of samples were accompanied with standard marker (50bp DNA). To measure fragment size, samples were run on a 1% agarose gel. Ten of the ninteen primers showed polymorphism. Statistical analysis of data was performed using POPGENE software. The avarage genetic variation was 0.189 in total samples and the maximum variation was found in samples from north of the Caspian Sea. Also, The maximume genetic distance was between north of the Sea and Golestan coasts in the south (0.089).The minimum genetic distance was between Mazandaran and Guilan coasts (0.001). The UOGMA dendogram showed two clusters. The samples of Mazandaran, Guilan and Golestan coasts were placed in one cluster and samples of the north area in another. The genetic diversity was significantly different between samples of the north area and Golestan coasts (P<0.05). We found a significant genetic divergence between some samples and therefore suggested at least two genetic groups of Mnemiopsis leidyi in the Caspian Sea.

The effects of modified atmosphere packaging (MAP) on the shelf life of Stellate sturgeon, Acipenser stellatus, fillets, (headed and gutted) stored in 4°C was examined and compared to vacuum condition. Three-layered packs (LDPE/EVOH/LDPE) were used with 110 mm of thickness. Fish stored in MAP conditions andvacuum samples (as controls), in different times, were evaluated for quality, chemical factors (TVN, PV and pH), microbial parameters (total viable count) and sensory factors. Different gases compositions of CO2, O2 and N2 were used for 8 treatments of MAP and vacuum packages. Mixed gases including 20-100% CO2, 35-80% N2 and 0-5% O2 were used for MAP conditions. Statistical analyses showed that quality, chemical, microbial and sensory factors were significantly different during cold storage (P<0.05) among treatments. Mixed gases showed no inhibitory effect on spoilage factors (chemical and microbial count), but the spoilage progress was delayed.Increasing of the chemical, microbial and sensory changes in control samples were between 9 to 12 days but in MAP samples were 15 days, and in some such as "D pack" were even more. The "D pack" with mixed gases including "CO2 (60%) and N2(40%)" followed by the "G pack" including "CO2 (60%), N2 (35%) and O2 (5%)" were the best formula with a shelf life of at least 15 days. When CO2 concentration was increased, amounts of TVN and Microbial community were decreased in MAP packs and the shelflife was increased. The results also showed that storage of Stellate sturgeon fillets at -4oC in MAP condition prolongs storage time and increases the product shelf life even after 15 days.

This study was conducted to assess the effect of different levels of temperature on survival, growth and reproduction of adult Caspian Sea Pontogammarus maeoticus. Temperature effects were studied in 5 thermal levels (15, 20, 25, 30 and 35oC) where salinity was constant (7.1±0.2ppt). The sampling was made from Hassan-rud coastal area in Guilan province. The results showed that survival was maximum at 20oC (95.56%) with higher temperatures showing a significant descending trend in survival (P<0.05) in which all samples perishedonts" day at 35oC treatment. The number of produced brood followed a significant ascending trend from 15oC to 25oC treatments and reached its climax at 25oC (117.3±12.2 broods). The minimum value for produced brood was reported at 15oC treatment (21.3±2.4 broods). A significant persistent increment of growth rate was observed throughout all treatments (P<0.05) where the maximum and minimum values were observed for the final (5.76±0.1 mm) and the first (1.77±0.06 mm) treatments, respectively. We suggest 25oC, 20oC and 30oC temperature treatments for producing the maximum brood per unit of time, the highest survival rate and the maximum growth, respectively. The temperature 25oC is defined as the best for aquaculture of pontogammarus as livefood of aquatic organisms.

To determine the genetic diversity of Rutilus frisii kutum, 25 samples were collected from Gharesou and Gorgan-rud rivers in April 2008. The genomic DNA was extracted from the caudal fin using phenol- chloroform method and investigated with 10 microsatellite loci. All the 10 investigated loci were polymorphic and showed variability in the two populations of the rivers. The mean number of allele per locus at population level and the observed heterozygosity ranged from 4 to 13 and 0.22 to 1.00, respectively. The FST value between populations was 0.014 (P<0.05), and the analysis of genetic variation distribution indicated a very high within population variation (99%) while among population variation is low (1%). Highly significant deviation from hardy- Weinberg equilibrium was observed in both populations which can be attributed either to the presence of null alleles or to the genetic bottleneck. The results indicated a high level of genetic variation in this species and we concluded that there is more than one population of Rutilus frisii kutum in Golestan coastal waters.

An unidentified species of Palaemonidae was observed in the downstream of Bahmanshir River in 2008. We caught 472 specimens of the fauna and used FAO species identification sheets for species identification. Some of the specimens were also transferred to Aristotle University of Thessaloniki, Greece for final taxonomic confirmation. As a result, we could confirm for the first time the presence of the freshwater shrimp Exopalaemon styliferus (Milne-Edwards, 1840) belonging to family palaemonidae from Iran. This species has been recorded from the north coasts of Borneo and Indonesia westward through Thailand and India to Pakistan and from Iraq and Kuwait waters. Our finding extends current knowledge of the global distribution of E. styliferus.