Iranian Scientific Fisheries Journal
Year:2011 | Volume:19 | Issue:4 (73)|Papers Count:22

Concentrations of four heavy metals (Cd, Cr, Zn, and Pb) in the common carp (Cyprinus carpio) were assessed in winter, spring and summer seasons of the years 2008. Four coastal areas in the west and east, Gomishan Marsh and Gorgan Bay including 11 sites were sampled. After biometrical measurements of the fish, specimens of muscle (104) and liver (36) tissues were immediately frozen and transferred to laboratory for assessment of heavy metal concentration. Dry ash method and atomic absorption spectrometer (AAS) of Perkin Almer (400 model, German) were used to assess metals concentration. In the process, analysis of variance (ANOY A) and Tukey-test were implemented.Heavy metals concentration in kidney tissue was higher than muscle tissue. In carp muscle tissue, level of zinc was highest and the next categories were those of lead, cadmium and chromium, respectively. A significant difference was observed between chromium concentrations in muscle tissue of Cyprinus carpio with sex (P<0.05). The concentrations of heavy metals in liver tissues were higher than those 'of the muscle tissues and in all cases; they were lower than mean allowable concentrations of international standards (WHO, UK, MAFF and NHMRC).

This research was carried out for 10 successive weeks (2 weeks for adaptation and 8 weeks for culture) in summer 2008 at Abzisytan Shrimp Hatchery Center in Bushehr province. The effects of dietary nucleotides at 5 levels including 0.0% (control), 0.15%, 0.25%, 0.35% and 0.5% on the growth performance and whole-body composition of Epinephelus coioides was investigated. Juvenile fish specimens with average weight of 10.70±0.29g were fed by experimental diets for 8 weeks. The trial was carried out in 300 liter fiberglass tanks. The highest protein content was observed in 0.15% diet nucleotide and the highest fat in 0.15% and 0.25% diet nucleotide which showed significant difference with the control group (P<0.05). The highest and lowest ash content was observed in 0.15% and 0.35% nucleotide treatment, respectively. The ash content showed significant difference between 0.15%, 0.25% and 0.35% treatments and control group (P<0.05). Also, the 0.35% treatment had the highest water content (P<0.05). We conclude that at the level of 0.15% dietary nucleotide, better results are achieved in terms of whole-body composition.

We investigated production of single cell protein (SCP) from stickwater of kilka fish meal factory as medium usingLactobacillus acidophilus and Aspergillus niger. Stickwater was used instead of the standard media of bacterium and fungus in a batch culture method.Amount of biomass, COD, RNA and protein in the bacterium and fungus in control and stickwater treatments were investigated. In maximum growth time, amino acids profile of the bacterium and fungus were measured and compared between treatments. Bacterial biomass production in the control and stickwater treatments were 3.16 and 5.12g/1, COD reduction was 33270 and 53330mg/1, the measured RNA were 15.27% and 15.04%, the amount of protein were 71.13% and 68.37%, respectively. The difference between bacterium and fungus biomass production was slight. We found that the amount of the fungus biomass in control and stickwater were 6.31 and 7.28g/1, COD reduction were 47800 and 55200mg/1, RNA was 9.36% and 9.09%, the amount of protein were 51.36% and 48.66%, respectively. In both bacterium and fungus, the maximum and minimum amount of amino acid of the control and stick water was glutamic acid and methionin. The amount of methionin in bacterium was not different with fish meal and FAa reference and in fungus was a little lower than FAO reference. According to the results, application of pure stickwater was suitable for production of Lactobacillus acidophilus and Aspergillus niger.

The possibility of replacing fish meal with plant protein sources (soybean meal and com gluten) for beluga (initial body mass 159.55±2.14g) was studied in autumn 2009.Experimental feeds with 46.5% of crude protein, GE: 5.4 Cal g-1 in four replacement levels: 0, 270, 450 and 660 gr kg-1 were prepared and fish were fed on the diets for 60 days. Significant differences were found in growth performance (P<0.05) of different diets. Biomass gain, specific growth rate, feed conversion rate and protein efficiency ratio in fish feed with diet 1 was higher (P<0.05) that the other ones. However, growth performance in diets 2 and 3 were not significantly different (P>0.05). Moisture of beluga carcass fed with diet 4 was significantly higher (P<0.05) that the other diets. However, protein, fat and ash were not significantly different (P>0.05) among diets. The hematocrit percentage was significantly higher in experimental treatments 1 and 2 than 3 and 4 and the plasma glucose was significantly different between diets 1 and 4 (P<0.05).With decreased fish meal, significantly (P<0.05) decreased plasma cholesterol was found in diet 1 compared to the diets 3 and 4.Results showed that combination of soybean meal and com gluten is not a good substitute for fish meal and deceased growth performance of the fish.

The present study was carried out to find the probable effects of marine fish cage culture on benthic communities as pollutant and stress indicators. Also, the biotic health condition was assessed using ABC index, in Ghazale creek, Khore-Mussa area in northwest of the Persian Gulf.Monthly sampling from four stations was conducted from June 2007 to March 2008. Stations were selected according to distance from cages in Ghazale creek. The distances were immediately under the cages, 50, 150 and 400m from the cages. At each station, three samples for macrobenthos and one sample for sediment grain size analysis and total organic matter (TOM) were collected by Van Veen grab with 0.0225m2 area. The range of total organic matter percentage in sediments was (6.17-23.26) and the range of silt-clay percentage was (4.76-97.47).We found 12 macro benthic orders and Polychaets (60.62%), Mullusca (19.67%), Crustacea (16.49%) were the dominant groups. Macrobenthic abundance, biomass and diversity index value under cage station were less than those 400m away from the cages. Capitella sp. As opportunist species was dominant under cage station. This genus is introduced as the pollution indicator in the area. The result of ABC index show that under the cages and distances 50 and 150m away from the cages have average pollution, while the 400m distance from the cage (control site) is unpolluted.

The probiotic effects of inactive yeast, Saccharomyces cerevisiae var. ellipsoideus was studied on growth performance, survival and intestinal microbiota of beluga juveniles (Huso huso).The study was done in complete randomize design that included feeding of beluga juveniles with diets supplemented with 0 (control), 1, 2 and 5% yeast (4 treatments with 3 replicates). Beluga juvenile s (11.40±0.56g) were randomly allocated in 12 oval tanks at a density of 35 fish per tank and triplicate group were fed with experimental diets. At the end of the trial, growth factors (final weight, weight gain, SGR, CF) as well as feed conversion ratio (FCR), body composition (protein, lipid, ash, moisture) and intestinal microbiota (total viable bacteria and Lactobacillus spp. levels) were determined. Our results confirmed that juveniles fed on diet supplemented with 5% S. cerevisiae var. ellipsoideus had significantly higher final weight, weight gain, specific growth rate (SGR) and lower food conversion ratio compared to control and 1% treatment (P<0.05). However, there were no significant differences between SGR of 5 and 2% yeast treatments (P>0.05). The study of body composition showed no significant difference between treatments (P>0.05). Total viable bacteria and Lactobacillus spp. count were significantly higher in 5% treatment compared to control (P<0.05). However, there was no significant difference between Lactobacillus spp.levels in 5 and 2% treatments (P>0.05).

Regarding the key role and importance of Daphnia in aquaculture, particularly for survival and adaptation of fishes in larval stages, a comprehensive study on hatching rate of Daphnia ephippial eggs was implemented to obtain an optimum technique. The effects of abiotic factors was investigated on the hatching response of Daphnia pulex diapausing eggs collected from live food ponds in Cultivation and Breeding Centre of Gorgan. After isolation, the eggs were kept in dry and wet conditions at 4oC for 2 months in darkness. Following the preincubation period, the eggs in each group were subdivided into 2 parts and treated with 1% NaOC1 and distilled water. The effect of temperature levels (15oC, 20oC, 25oC) and photoperiod levels (12L: 12D, 24L: OD) were identified on the hatching of eggs in AdaM medium during 15 days. Results indicated that the exposure of wet-kept eggs to 12-hour photoperiod and 2YC without soaking in 1% NaOC1, caused the maximum rate and speed of hatching.

The histopathology of some important organs of perch (Sander lucioperca) and salmon (Salmo trutta caspius) were studied in the southern part of the Caspian Sea with emphasis on pollutants. Twenty perch and salmon individuals were captured from the southern region of the Caspian Sea, immediately subjected to sampling of the liver, kidney, gills, gonads and muscles which were fixed in 10% formalin. Five mm microscopic slides were prepared from the fixed samples using standard histological methods, and then studied under light microscope.Swelling, hypertrophy and hyperplasia, fusion of secondary lamellae and also congestion, hemorrhage and necrosis of the lamellae were observed in the gill of perch and salmon samples. Congestion, hemorrhage, degeneration and necrosis of the tubules, glomeruli and interstitial tissue of the kidney of the examined fishes were the most important observed signs. Histopathologic signs such as congestion and hemorrhage of the blood vessels, dilation and congestion of the sinusoids, hypertrophy, degeneration and vacuolation of hepatocytes and also necrosis of the liver tissue were the most obvious signs in the liver of the examined fishes. No pathological changes were seen in gonads and muscles. The results showed that the important organs of the studied fish have serious disorders and abnormal conditions, which could be due to the long term exposure to the toxic materials. In terms of public health, higher than standard levels of pollutants in fish body makes them unsuitable for human consumption.

Quality of tiger-toothed croaker stored in flake ice was studied for 19 days by sensory, chemical (total volatile basic nitrogen (TVB-N)), (thiobarbituric values (TBA)), pH and microbial (total viable count, TVC) methods. Sensory scheme was modified according to the panelists' perception and a specific schema was created for this fish. Sensory analyses showed that: "gills color and odor", "convexity of eyes", "peritoneum" and "elasticity of flesh" are the best sensory parameters. Results of sensory and microbial analyses had high correlation. Total viable count of flesh was 2.86 log cfu g-1 at first day and reached the limiting level of TVC (106) after 15 days of storage (P<0.05). TVB-N levels were 15.31 mg/100 g tissue at the first day of storage and reached 36.52mg/100 g at the end of storage day (P<0.05). Measuring amounts of TVB-N showed that total volatile basic nitrogen is a good quality index for tiger toothed croaker during ice storage. The initial level of TBA was 0.83mg of malondialdehyde per kg flesh (mg MDA/kg) and increased to 3.75mg MDA/kg at the end of storage. TBA levels were less than limiting level (5mg MDA/kg) over the period of storage. According to the results, shelf-life of tiger-toothed croaker was determined 15 days during ice storage.

We determined bioaccumulation of heavy metals (Cd, Pb, Ni and Hg) in the muscle, gill and liver organs of Barbus xanthopterus in summer 2009 in Karoon River, south west of Iran. Gill net was used to sample 48 random size fish specimens from Karoon River downward of Ahwaz city (Shekariyeh 3 village). The tissues were extracted and the elements were determined using atomic absorption spectrophotometer. Concentrations of heavy metals Cd, Pb, Ni , Hg in muscle tissue of Barbus xanthopterus were 1.679, 2.37, 1.16, 1.29mg/kg dry wt and in gill were 2.17, 2.92, 1.44, 1.34mg/kg dry wt and in liver were 1.92, 2.79, 1.31, 1.43mg/kg dry wt, respectively. All the results were statistically significant (P:S 0.05). The concentrations of heavy metals were higher than standards of the World Health Organization (WHO) in the muscle tissue of Barbus xanthopterus in Karoon River.

Presence of hepatopancreatic parvo-like vines (HPV) disease was assessed from June until October 2009 in Litopenaeus vannamei hatcheries and grow-out farms of the Bushehr province. Samples were collected from 6 hatcheries and 6 grow-out farms located in coasted areas. From each hatchery, 100 PL samples with average age PL5-PL8 and 20-30 samples from each grow-out farm with average age 105 to 120 days were collected. The samples were divided into three groups, one used for gross sign and wet mount with Gimsa, the second group was preserved in Davidson Fixative and used for histopathology and the third group was fixed in ethyl alcohol 95% and used for polymerase chain Reaction (PCR). In gross sign 30%-40% of the shrimp showed different sizes and some were smaller than the others. In the wet mount group with Gimsa staining of hepatopancrease, the inclusion body with basophilic color was seen. The histopathology indicated that the hepatopancreatic cell was infected and the basophilic inclusion body observed in many samples. The PCR examined with IQ 2000 Kit was negative. The rate of infection (ROI) was 1.1% for hatcheries and 32% for grow-out farms.

Temporal and spatial distribution of fish larvae population in eastern and western parts of Khure-e-Mussa channel in Khuzestan province (Persian Gulf) was studied during 2007-2008.Monthly samples were collected by 300llm mesh size plankton net during which 9440 larvae were collected. Totally, 22 families were identified including Bregmacerotidae, Callionymidae, Carangidae, Clupeidae, Cepolidae, Cynoglossidae, Gobiidae, Leiognathidae, Mugilidae, Platycephalidae, Scaridae, Sciaenidae, Scatophagidae, Scorpaenidae, Sillaginidae, Soleidae, Sparidae, Stromateidae, Syngnathidae, Engraulidae, Trichiuridae, Triacanthidae.The most frequent families were Gobiidae (22.26%), Clupeidae (17.61%), and Sparidae (8.77%), respectively. The highest densities of larvae were observed in beginning of spring.Two peak of population was observed. The first one in early spring (April) and the second peak was in mid-summer (August and September). Cluster analysis based on average annual abundance of 12 important families classified stations into three groups with 70% similarity.The results of cluster analysis separated western stations 1, 2 and 3 from others. Higher densities of fish larvae in the western coast of Khur-e-Mussa channel showed that western parts better for nursery grounds for the studied fish larvae.

The effects of feeding frequency on growth performance, feed conversion ratio and survival of post-larvae Indian white shrimp, Penaeus indicus were evaluated in a 56-day study. The study was conducted in sixteen fiberglass tanks provided with aerated recirculating water with four replicate tanks for each treatment. Twenty post larvae with a mean weight of 1.56±0.02g were hand-counted and stocked into each of the replicate tanks and fed 2, 4, 6 and 8 times a day, respectively. Final body weights were measured significantly lower at 2 and 4 times/day (5.76±0.08 and 5.96±0.15g, respectively) than 6 and 8 times/day (8.54±0.16 and 8.31±0.19g, respectively) treatments (P<0.05). There were significant differences for the Feed Conversion Ratio (FCR) of shrimps fed 6 and 8 times/day with other treatments. Thebest mean FCR was obtained from the sixth daily-feeding (P<0.05). The Specific Growth Rate (SGR) of shrimps fed 6 times/ day was significantly (P<0.05) higher (3.03±0.04%) than shrimps fed with all other feeding regimes, while shrimps fed 8 times/ day had a higher SGR (2.95±.05%) than shrimps fed 2 times/day (2.36±0.06%) and 4 times/day (2.39±0.11%). Survival rate was significantly different (P<0.05). The best mean survival rate was obtained from 6 times/day feeding (P<0.05). There were significant differences for survival rates (P<0.05). The water quality parameters (salinity, dissolved oxygen and temperature) were not different among treatments. However, some water quality parameters (ammonium, nitrate, nitrite, phosphate and pH) were significantly different among the treatments. Results suggested that there was an advantage in feeding P. indicus more frequently than 4 times per day.

This project was carried out in the year 2003 in Khuzestan province waters to determine the best artificial propagation techniques for mass production of Barbus xanthopterus. The fish is one of the most valuable and economic species in the area. The propagation was started in late March and continued till late April while suitable temperature was 21-24.50 C. A number of 23 female brood stock with mean weight and length 3.85±0.45kg and 64.95±21 em respectively with a sex ratio of 2: 1 male to female were used in the process. The amount of hypophysis injection was 4mg/kg weight of fish and two injections with 10-12 h interval to 10: 90 were undertaken. Spawning success was 87% in broodstock. Latency period was 15-17h and the incubation duration was 59-60h in 23-25oC.The fish eggs has a low stickiness and the count of dry and water-absorbed eggs were 480±32 and 287±25g, respectively. In the twice-injected broodstock, the fertilization rate was 77.22±3.1%, the hatching rate was 81.2±1.89% and the survival rate was 83.4±2%. Size of the dry and water-absorbed eggs was 1248±45 and 2110±125, respectively. Washing time with fertilization liquid was 10 min for removing stickiness. In the end, 660 thousand larvae were produced and released to earthen ponds for culture.

The swim bladder status of false trevally (Lactarius Lactarius) was studied from November 2007 to October 2008 in coastal waters of the Oman Sea. A number of 702 swim bladders of false trevally specimens were collected randomly from catch composition of gillnets and bottom trawler. False trevally has an unusual swim bladder, as the first and the second spines of its anal fin are joined that creates a single bone, which is called anchorage bone, and passes from the middle of the swim bladder and 2 lobes of the gonad and connects to the 10th vertebra of the spinal column. Another ending of this bone is wide and reaches anal fin base. This bone is like an anchorage for swim bladder of false trevally and it functions as a center of gravity of the fish in anal fin base. It firms the exterior part of the fish body, so the fish swims through rough waters easily.

The changes in density and biomass of macrobenthos were seasonally investigated from winter 2005 till fall 2006 in southern Caspian Sea. Samples were taken with a 225cm2 Van Veen grab from depths of 7 and 20 meters along two transects: Line 8 area (western part) and Radio Darya area (eastern part). Totally, 5 classes of macrobenthos were identified of which the most abundant populations were Polychaeta 68.7%, Oligochaeta 14.6%, Bivalvia 8.5%, Crustacea 8.2% and Gastropoda 0.08%. The maximum density (4251.8±1419 (ME±SE) ind/m2) of macrobenthos was observed during summer in the depth of 20m of Radio Darya area, while the minimum density (725.9±64.5 (ME±SE) ind/m2) was observed during spring in the depth of 7m in the same area. Between the two studied depths, the mean annual density in 7m depth (2266.7±350.3 (ME±SE) ind/m2), was higher from 20m depth (1977.8±290.1 (ME±SE) ind/m2). The maximum biomass (475±243.8 (ME±SE)g/m2), of macrobenthos was observed during autumn in the depth of 20 meter of Radio Darya area, while the minimum biomass (0.3±0.1 (ME±SE)g/m2), was observed during winter in the depth of 7m in the same area. Between the two studied depths, the mean annual biomass in 20m depth (184.8±24.6 (ME±SE)g/m2), was higher from 7m depth (73.7±24.6 (ME±SE)g/m2). Generally speaking, the eastern part of Chalus coast had more density and biomass compared with the western part.