NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2013 | Volume:7 | Issue:2 (26)|Papers Count:13

The present study was conducted to determine the concentration of heavy metal, Zinc (Zn) in the muscle and liver tissues of the Chub (Squalius cephalus) in Tajan Rive, Mazandaran Province in 2009. Fish samples were collected by electro-shocking at four stations. Microwave digestion method and atomic absorption spectrometry were employed to measure the concentration of Zn in samples. The results was showed that Zn accumulation in liver were greater than muscle of the S.cephalus (p<0.05). The lowest concentrations of Zn were observed in 4th station. The comparison of the results of this study with the recommended world standard limits showed that the concentrations of Zn in liver were lower than World Health Organization and higher than standard limits of UK Ministry of Agriculture, Fisheries and Food, National Health Council and Australian Medical Research. In the muscle tissue was lower than World Health Organization, National Health Council, and Australian Medical Research but higher than standard limit of UK Ministry of Agriculture, Fisheries and Food.

To determine levels of some hematological and biochemical factors in 60 specimens (6, 12, 24 and 36 months) cultured grass carp (Rasht, Guilan Province) were sampled and blood samles were collected from caudal fin and then were analyzed. In this study, average of RBC, WBC, HCT and Hb were 1911500/mm3, 14320/ mm3, 36.3% and 7.53 gr/dl, MCV, 199.46 femtolit, MCH, 39.73 picogr., MCHC, 20.55 gr/dl. Lymphocytes, Neutrophils, Monocytes and Eosinophils were 70.91%, 26.7%, 1.06% and 1.28% and concentrations of Glucose, Cholesterol, Triglyceride and Protein were 130.6, 278.7, 243.9 mgr/dl and 3.6 gr/dl. In compared to other age groups, MCHC of 36 months old group increased, but both MCV and Triglyceride decreased (p<0.05). MCH of 6 months old group was more than other age groups (p<0.05). While in other factors such as number of WBC, differential counting of WBC, Cholesterol and Protein had not observed significant difference (p>0.05).

This research was conducted in a trout farm in Kohkiloyeh and Boyer-Ahmad Province. The main object of this study was comparing of two sources of astaxanthin (synthetic or algae, Haematococcus pluvialis) in feed on reproduction efficiency of rainbow trout. So, algal astaxanthin (Haematococcus pluvialis) in the three levels of 2.67, 3.55 and 8 gr/kg food (T1,T2, T3) and synthetic source in three levels of 40, 80 and 120 mg/kg food in diet (T4, T5, T6) examined on 140 trout broods (3-4 years) for 4 months, before the spawning season. Therefore, it was considered 7 groups consisting 6 treatments of two different astaxanthin sources and a control (without astaxanthin). Reproduction efficiency analyzed through reproduction indices such as egg diameter, fecundity, and fertilization, survival, hatching and eyed egg rates. Significant difference between treatments in terms of fecundity, eyed eggs rate and the number of eggs per gram was observed (p<0.05). Although in some factors such as egg diameter and fertilization rate, no significant differences was observed. By increasing level of astaxanthin in both sources of algal and synthetic, hatching and eyed egg rates increased from 40 mg/l to 120 mg/l, but the effect of alga source on these indices was more perfect. Considering the results, the best result related to treatment of 8gr/kg alga (T3). Observations during this research indicated no disease and mortality and also proper coloration and freshness of fishes. Overall the results asserted that the application of astaxanthin improves reproduction performance of rainbow trout. It also concluded that natural astaxanthin (Haematococcus pluvialis) for the reason that contains supplementary nutritious, is extraordinary preferable than synthetic astaxanthin to improve reproductions indices and egg quality of female rainbow trout.

In this study the effect of male broodstock age on artificial propagation efficiency was studied during 2011 breeding season in common carp. For this reason, eight males (2 and 3 years old) and 4 females (3 years old) were fertilized separately. The combination of stripped semen from 2 and 3 years old males were used in treatment 3. Result showed, percentage of motile spermatozoa and sperm concentration were significantly higher in 3 years old males (p<0.05). The maximum fertilization and survival rates were observed in the treatment including collected semen from 3 years old. Based on current research, stripped semen from 2 years old males had the highest fertilization performance in common carp.

583 specimen of Palaemon elegans were collected during December 2010-June 2011 in associated with Gomishan Wetland pools, Caspian Sea, by using cast-net (mesh size 6 mm) monthly with mean depth of 1m. Results showed that females grew to a larger size than males. Maximum total length (Tl), carapas length (Cl), propodit length and body weight (Wt), were 44.70 mm, 13.70 mm and 32.80 mm and 2.70 gr., respectively in females and 40.10 mm, 11.20 mm and 28.30 mm and 1.41g, respectively in males, too. The sex ratio was 1:1 (males, 55.23%: females, 44.75%) showed significant difference (P<0.05). The length-weight relationship for the males and females were determined as W=0.00003TL2.864 and W=0.00001 TL3.088, respectively. The Patterns of growth were observed isometric in the females and negative alometric in the males. The Lm50 of females was estimated 34.52 mm.

The marine rotifer Brachionus plicatilis is extensively used as a major live food in fish larvae culture all over the world. In the present study an attempt was made to find out the effect of temperature and feeding conditions on the size of rotifer (Brachionus plicatilis), that was surveyed in Aquaculture Department of Persian Gulf and Oman Sea Ecological Research Institute (PGOSERI) (located in Hormozgan Province) on December 2010. The rotifer was cultured at tree temperature ranges (25, 30 and 35oC) and fed with two species of microalgae including, Nannochloropsis oculata, Chlorella spp. and mixed of Chlorella spp. & Nannochloropsis oculata. The rotifers were introduced at stocking density of 6 ind/ml for each treatment. In this experiment, the pH was between 7.7 until 9.9, salinity 25 ppt, the density of rotifers in mild aeration was provided and the treatments were exposed to 1500 lux light intensity. The experiment carried out for 7 days. Results revealed that increasing of temperature cause decreasing in the size of length and width of rotifer. The highest size of rotifer was observed at 25oC and the lowest size at 35oC. There was a significant difference between the size of the length and width of rotifer cultured in 35oC and the other levels of temperatures (p<0.05). Also, the combined effect of temperature and algal diets on rotifer size were significant (p<0.05). In all of the experiments, the best result was observed conducted at 35oC temperature using mixed of Chlorella sp. & Nannochloropsis sp. as the main food. (length 118.26 & width 94.75 mm)

Rainbow Trout, like other fish need to n-3 and n-6 fatty acids for natural growth. In this research, the effects of different oils on the liver of juvenile trout were investigated. Thus, Viscera-Somatic (VSI) and Hepato-Somatic (HIS) indices and also fatty acid composition of fish liver were studied, while juveniles fed by foods including Canola, Sunflower and fish oils. For 60 days, the juvenile trout in initial weight of 5.95±0.0.65 g were fed. As a result of the experiment, VSI was 17.87±1.1, 18.05±0.15 and 17.2±0.18, and HIS were 1.55±1.09, 1.65±1.05 and 1.61±0.42 in groups fed with fish, Canola and Sunflower oils, respectively. There was significant difference between fish oil group and others in the amounts of PUFA, n-3 and n-6 (p<0.05), while MUFA, UFA and SFA did not show significant difference (p>0.05). The maximum ratio of n-3/n-6 was found in the fish oil and the minimum in the Sunflower group. The results also showed that highest ratio of DHA+EPA was obtained in treatment of fish oil with 37.41 g/100g and lowest ratio in the treatment of Sunflower whit 19.51 g/100g.

In this study, review of catch process and fish stocks of kutum, mullet, common carp and roach in the Caspian Sea during the years 1999 to 2008 in Golestan Province was conducted. In this study, annual catch data from 20 active seine cooperative companies in Golestan Province was taken over 10 years and were analyzed. The results showed that catch of kutum and mullet in west coast (Miankaleh) more significantly than east coast (Gomishan) and carp catching on the east coast is more than the west coast (p<0.05). But roach catching in the two regions was not statistically significant (p>0.05). The amount of catching has declined for the four species of teleosts that indicates fish stocks in the Caspian Sea reduced. The highest ratio of catch in over 10 years of fishing in the Golestan Province were common carp>mullet>kutum>roach with the 39.23, 33.76, 26.54 and 0.47 percent of total catch. It seems that stocks of kutum, mullet, carp and roach are declined in the Caspian Sea.

This study represents population genetic structure of the common kilka in the Southern Caspian Sea (Gilan Province). Totally, 60 individuals of adult common kilka from two seasons were sampled. Fifteen sets of microsatellite primers were developed from American shad (Alosa sapidissima), Pacific herring (Clupea pallasi), Atlantic herring (Clupea harengus), sardine (Sardina pilchardus) tested on genomic DNA of common kilka. Allele frequencies, the fixation RSTindex and FST on AMOVA test, observed and expected heterozygosity H-W equilibrium, genetic distance and genetic identify were determined at disomic loci amplified from fin tissue samples using GenAlex and uvitec software. At this point only the five successfully used primer sets should be mentioned (Cpa6, Cpa8, Cpa104, Cpa125, AcaC051) and were used to analyze the genetic variation in adultsof the common kilka population. Analyses revealed that average of alleles per locus was 14.4 (range 5 to 21 alleles per locus). Both of sampled seasons contained private alleles. Average observed and expected heterozygosity were 0.153 and 0.888, respectively. All loci significantly deviated from H-W equilibrium. Basis on AMOVA for both RST values among pairs them ranged 0.113 (Nm=1.96) and indicated a significant difference between the two seasons (p£0.01). The genetic distance between populations was 0.344, which indicates that the genetic difference among the studied populations is pronounced. These results support the existence of different genetic populations along the South Caspian Sea coastline (Gilan Province).

This study was conducted in order to examine the effects of adding multi-enzyme Avizyme on the growth indices and body carcass compositon of western white shrimp with initial average weight of 2.5±0.5 gr. The 21 plastic tanks (50-liters) contains 525 larvae shrimp in 7 treatments (3 treatments containing enzyme, 3 treatments lack of enzymes, 15, 30 and 45 percent canola meal and 1 treatment (With 30% fish meal and canola meal without multi enzyme as control) were used. The results showed that adding 30% canola meal containing 0.5 percent multi-enzyme Avizyme instead of fish meal have no negative impact on growth performance and improved growth performance and survival rate. The maximum and minimum survival rates was observed in 30% canola treated with 0.5% multi-enzyme treated and 15% canola treated without multi-enzyme with 84% and 57.8%, respectively. The control group had significant difference with other treatments as fat, fiber and ash ration (p<0.05). It seems usining the multi-enzyme treatment contain 30% and 45% canola with 0.5% multi-enzyme and 30% canola without the multi-enzyme can used instead of fish meal because of economical and food cost state.

Present study is carried out in 10 sampling sites from July 2007 to June 2008. Sampling stations were chosen according to the result of the Atrak River survey that was done along the river before the study gets started. Samples were collected twice per month from each site. 100 lit of water were filtered with plankton net (20 m mesh size). The phytoplanktons that were identified from samples are as follows: Chlorella, Stigeoclonium, Ankistrodesmus, Closterium, Gyrosigma, Eremosphara, Oscillatoria, Anabaena, Chlamydomonas, Diatoma, Nitzschia, Navicula, Oocystis, Meridion. Results indicate that Chlorella had the most frequency (n=1055) and Meridion had the least (n=120). Also sampling site number 6 (Najaf-abad Dam) had the highest phytoplankton frequency (n=753) and sampling station number 3 had the minimum (n=389). Overall, the results demonstrate a low diversity of phytoplankton and also low number of specimens in total sampling (n=5852). Therefore, one can come to conclusion that the population of phytoplankton in the Atrak River from the density and frequency point of view is not considerable.

This study pursued the molecular identification of fish species from processed products, Macruronus magellanicus and Scomberomorus commerson fillet, which a priori belonged to two species in Iran for human consumption. DNA barcoding was used direct sequencing of about 650 bp of mitochondrial genes Cytochrome Oxidase subunit I (COI), NCBI and The Barcode of Life Data Systems (BOLD). It was found that the label listed on a fillet of higher economic value has been replaced with less economic value fish fillet. Results need to worry about quality control and authentication of so processed fishery products are expressed.