NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2013 | Volume:7 | Issue:3 (27)|Papers Count:18

Marine organisms, especially molluscs, have the ability to accumulate heavy metals from the environment in which they live. They are useful indicators organisms for heavy metal bio-monitoring in aquatic environments. Thus, Saccostrea cucullata samples were collected from four sites on the southern intertidal coast of Qeshm Island on the Persian Gulf of Iran and were transferred to the lab in the rimy form. The soft tissue of the samples was carefully separated from shells and after acidic digestion (using nitric acid 65% v/v) the prepared samples were evaluated for Cd, Pb, Cu, and Zn using a flame atomic absorption spectrophotometer (model 67OG) and a graphite furnace atomic absorption spectrophotometer (model 670G). The results showed that in the all sites, the Cd, Zn, and Cu levels in soft tissues were higher than in the shells, but the Pb level was higher in the shells than in the soft tissues. Also the results also showed that the highest values of Pb and Cd were found in Naz Islands and the lowest concentrations of Pb and Cd were observed in Shibderaz. The highest concentrations of Zn were found in Zeytoon Park and the lowest concentrations of Zn were found in Ziartgah shahshahid. The highest amounts of Cu were observed in Ziartgah shahshahid and the lowest concentrations of Cu were in Zeytoon Park. Therefore, the concentration of these heavy metals in bio-indicators is dangerous alarm for native consumers and it needs continuously their bio-monitoring.

Investigation of abundance and distribution of biological assemblages and compared them with similar ecosystems could provide precise information on the extent of contamination. Due to entry of industrial, urban and agricultural wastewaters to the Atrak River, study of biological biomass especially zooplanktons as a part of food web to be very important. This study conducted monthly in one year period between 2007-2008 in 10 stations. Sampling were done by filtration of 100 liter water by net (50m mesh size) and fixed in formalin 4% and transferred to the laboratory for identification. In this study, three phylum include Ciliophora, Arthropoda and Rotifera indemnified that abundance of them were 20.09, 12.61 and 7.36 individual number per liter, respectively. Among these three phylum 8 genera identified including Chilodonella, Colpoda, Vorticella, Daphnia, Cyclops, Asplanchna, Ascomorpha and Brachionus. Chilodonella and Ascomorpha with 7.86 and 2.4 number/lit had the highest and lowest in number. The maximum and minimum Shannon and Simpson Biodiversity Indices were for spring and winter seasons. Also the trend in monthly changing of water temperature show that in March and October population was the highest and in winter with the decrease in water temperature and drop of food availability the zooplankton population decreases dramatically. In general, results indicate that the Atrak River is poor in diversity and frequency of zooplankton population.

In recent years, Caspian Sea is exposed to oil pollution caused by the extraction and transportation of oil. This study was achieved to determine the ability to accumulate metals nickel and vanadium as an indicator of oil pollution in liver and heart tissues of Persian sturgeon (Acipenser persicus). So, study was performed on 27 samples of this species in the southern coast of the Caspian Sea in 2011. The samples were collected by the fisheries of the southern coast of the Caspian Sea and then into two workshops at shahid Behshti of Gilan and Shahid Marjani at Golestan Province were transferred. Heavy metals concentrations were determined by the atomic absorption device (shimadzu, AA-670). Nickel concentration in liver and heart tissues were measured 0.13 and 0.44 mg/g dry weight, and vanadium in liver and heart tissues 0.34 and 6.13 mg/g dry weight, respectively. Concentrations of the tested elements varied in the tissues in this sequence liver>heart for vanadium as well as liver>heart for nickel (P<0.05). Result revealed a significant difference between nickel and vanadium in liver and heart in (A. persicus). The high metal concentrations in liver could be due to the metabolically activities of this tissue. Also the lower concentration in heart could be due to blood pumping activity. The conclusion to draw is that the high concentration of vanadium, compared to nickel, in the different tissues of the studied samples and oil contamination in the Caspian Sea may be the main source for these metals.

The effects of Captan poison that use large quantity in agricultural fields, especially in the north of Iran, was studied on 180 pieces 3-5gr fingerlings Ctenopharyngodon idella in this research, aim to determine the 50% lethal concentration (LC50) in 96 hours. These experiments carried out in static condition and based on (O.E.C.D, 2001) standard method in 4 days, and were controlled water physicochemical parameters including; pH, total hardness, dissolved oxygen and temperature. During experiments, reaction and behavior of the fingerlings exposed to poison was surveyed. Early experiment for find of mortality ration with released the number of 10 fish per aquarium were achieved into a 20 lit aquarium and continuously aerated. Lc50 value of Captan poison in 96 hours was calculated 0.9 mg/l for fingerlings C.idella and also M.A.C value (Maximum Allowable Concentration value) was determined 0.09 mg/l. Then, to determining effect Captan poison on blood indices with keeping to observation standard condition, fish in laboratory placed in concentration 25%, 50%, 75% of LC50 96h Captan ordering (0.225 mg/l, 0.45 mg/l, 0.675 mg/l) for 7 days and was proceed blood sampling. Results showed decreasing values of lymphocyte, hemoglobin, red blood cells, white blood cells, hematocrit, eosinophil (except from treatment 50%), MCHC and increase the values of MCH (except from treatment 25%), MCV (except from treatment 25%) and monocyte, neutrophil.

Foodborne illness resulting from the consumption of contaminated food and the most causative agents are pathogenic bacteria. Foodborne illness also arises from improper handling, preparation and food storage. This study was conducted to evaluate for microbial contamination of commercial ice for food storage in Khuzestan Province in 2011 (spring, summer, autumn and winter). Samples were collected of two factories of ice and market of Khoramshahr. Both microbial and chemical measurements were performed on the samples and the results analysed. The bacterial isolates obtained from the ice samples include E.coli, Staphylococcus aureus, Citrobacter and Enterobacter. The results showed the difference between the autumn and summer seasons contamination was significant (P<0.05), but the spring and summer samples had not significant different (P>0.05). The most contamination in three zones was observed in autumn season. The application of HACCP good management regulations for water and ice distribution system for harbours should use to improve the standards of fishery industry.

Nowadays, the soil erosion has been known as disaster for human life and richness. The aim of this study, to understand the effects of Lar Dam construction in hydraulic fluctuation and suspended sediment load on aquatic fauna of Haraz River. Therefore, the data sets of water discharges and suspended sediment of Lar-Polor station that located in downstream of dams before dam constructed (1968 until 1980) and after dam constructed (1981 until 2001) were used. The results showed that before construction of dams, water discharges and suspended sediment discharges have low coefficient of relations but in after of dam constructed, have good relations between water discharges and suspended sediment discharges. However, for longer times sedimentation was increased when released to river would be affected on benthic fish feeding in downstream of Haraz River.

In this study, a 8-weeks feeding trial was conducted to evaluate the effects of diets with different level of fish oil and soy oil on O.mykiss growth performance and body composition analysis. Fingerling O.mykiss with the average initial weight of (10g) were fed with3 different diets which contained 40% fixed amount of protein diets. For all groups fixed amount of %55 fish flour 10% wheat flour 20% soy flour and 5% additives while the amount of fish oil and say oil were different in diets for first group (control group) 10% fish oil second group 10% say oil and for third group 5% fish oil and 5% soy oil were added to their diets and they were investigated. 540 fingerling O.mykiss randomly assigned to 3 groups and each group contained triplicates (60 O.mykiss in each pool). After a 8 week feeding trial result showed that change in the amount of fish oil and soy oil in diets have effects on moisture an fat (P<0.05) and it have no significant effect on ash and crude protein (P>0.05) also the changes in the amount of fish oil and soy oil have effects on the most of growth factors like GR, BWI, but they have no effect on CF, FCR & SGR.

One practical way to reduce the entry of harmful elements from the sewage that runs from breeding farms into the sea is to cultivate biological indicators like species of algae in the sewage channel of the farms. In this survey sea lettuce, U.lactuca was planted at the sewage of shrimp ponds in Delaware region in Bushehr province and it was monitored. To study the changes, samples of water from the entry water of the pond, the sewage, and the algae were collected at the beginning and end of the period, and the samples were tested. Results of measurement of sodium, potassium, total hardness, calcium hardness, electrical conductivity, nitrate, phosphate, and salinity in the entry water, the sewage, and algae, in natural and cultured samples showed that the species studied responded appropriately to the new environment, and due to the increase in sodium, potassium and nitrate in the samples grown in shrimp ponds sewage, compared with the natural habitat of the studied samples, and also preserving the absorption of other materials and elements, it appears that the uptake of sewage from the ponds can reduce the content of the element. Statistical analysis of the characteristics of algae grown in the sewage of the ponds showed no significant difference compared with the natural habitat. Since separating these species from their natural habitat and planting in new habitats can cause stress in these species and consequently decline their growth, and they need a longer period to adapt to the new environment and continue to grow normally, it can be concluded that these species can grow more in longer periods. However, this amount of absorption makes it possible so that it can be used to absorb the nutrients found in the sewage of shrimp ponds, and the sewage of shrimp ponds enters the sea with less contamination, and leads to reduce the contamination of the Persian Gulf.

The purpose of the present study is to determine the levels of heavy metals cadmium, lead and mercury in muscle and shell in cultured shrimp, Fenneropenaeus indicus. At first, 6 kg shrimp samples (90 pieces) were prepared from Hormozgan province. Elements were assayed by using Perkin Elmer 4100 atomic absorption using one-way ANOVA. The results showed, average mercury levels in muscle and skin, respectively, 0.017±0.002 and 0.025±0.001 mgKg-1. Average lead levels in muscle and skin, respectively, 0.072±0.003 and 0.107±0.006 mgKg-1. Average cadmium levels in muscle and skin as well as the 0.045±0.002 and 0.056±0.009 mgKg-1. Heavy metals in cultured shrimp muscle was lower than shell. High levels of heavy metals in muscle and skin were Pb<Cd <Hg. Cd levels in muscle were higher than the World Health Organization and FDA standards.

The survey effect of salinity and turbidity performed on Rutilus frisii Kutum juveniles with aim, which was determined about survival rate and histological changes in gill tissues. Juveniles were provided from the Rajai’s fish propagation center and then examined in Caspian Sea Ecology Research Center laboratory. The juveniles were investigated on three weight group (200<400, 400<600, 600<1000 mg) and in fresh water and Caspian Sea water (12.5 ppt). Also, six turbidity levels (50 FTU, 430 FTU, 2600 FTU, 7800 FTU, 15600 FTU) were probed in freshwater during 168hr. Each treatment had three replications. The results showed that there was a significant difference among treatments in the different levels of factors, (p<0.05). The juveniles’ survival rate has decreased than control treatment in brackish water and turbidity in freshwater. It was demonstrated that with increasing fish weight, therefore, the survival rate is increased. However, gill tissue of juveniles under turbidity and salinity stress became short (necrosis) and thick (edema and hyperplasia) in the end of experiments. The juveniles gill tissues were not changes in the river clear freshwater. Although the survival rate of juveniles is acceptable in this study, but there was abnormal changes in the structure of them gills. The little changes was observed in group of 600-1000 mg. It appears that this change will cause a disruption in trend of juvenile’s growth.

In this study, some biometric characteristics were studied in three lagoons, Almagol, Ajigole and Alagol in 2009-2010. Sampling take place monthly using collapsible traps (Funnel Trap). In this study the max 2310 male and 1779 female specimens and the lowest 594 male and 665 female specimens were in the Ajigol. In the three lagoons, females were smaller than males. Comparing the average mean length males and females showed significant difference among the Ajigol with the other lagoons and the Alagol with the other lagoons, respectively (P<0.05). In length-weight relationship, correlation coefficient was recorded as r=0.97 and r=0.96 for male and female, respectively. The growth pattern was minus algometric. Maximum CPUE value was 34.67 g/trap in spring, in the Alagol and minimum CPUE, 0.56 g/trap in winter for the Ajigol. However, invasive Macrobrachium nipponense shrimp into Golestan lagoons effect on their ecology and food web.

Present study was done in order to evaluate the effect of Bio-mos (Mannan Oligosaccharide) as a kind of prebiotic on growth and survival of juvenile wild carp. This research was designed a completely randomized design in four levels of 0, 0.2, 0.4 and 0.6% bio-mos and in four treatment with three replicates. 35 carp juveniles with average weight of 10.8±0.4 gr. were stocked in each tank and fed during 8 weeks. The results of statistics analysis showed the positive effect of increasing level of bio-mos on some of the nutrition and growth indices like general weight (WG), special growth rate (SGR), condition factor (CF), and survival rate (SR) of wild carp. So that in the level of 0.6 % bio-mos, the amount of mentioned factors increased in comparison with other treatments. Results of this study showed that diets with 0.6 % supplementary bio-mos have effects on increasing of operation of growth and nutrition efficiency in wild carp. The results of chemical analysis of body composition did not show any significant differences between treatments (P>0.05). Also this prebiotic in level of 0.4 and 0.6 can be a suitable supplementary in the diet of wild carp.

This work aims to investigate effects of physico-Chemical parameters of soil environment, which in turn have an impact on water quality and finally on production of warm water fishes efficiency during culture period. Water and soil samples obtained with commonly methods before the pond filling with water from 6 different fish ponds around Gonbade Kavous city, East of Golestan province for physically and chemically analysis. Totally three times sampling of water was done bimonthly. Although phytoplankton and zooplankton Samples were collected in different ponds at different months for identify analysis. The results showed correlation relative between PO4, CaCo3, EC, Organic Carbon, pH, Total Nitrogen and Total Organic Matter of soil with different parameters of soil and most of water parameters at different months. The present study results indicated Soil-water interactions can be have strongly impact on water quality. So, soil quality should be considered in fish ponds management.

Health status information of 23, 21 and 20 breeding and rearing rainbow trout farms were gathered as questionnaire 2006 to 2008, respectively. The selected farms were located in Haraz, Dohezar and Sehezar regions of Tonekabon, Sari and Chalous. The results showed that farm production have increased from 75.3 tons in 2006 to 106.4 tons in 2008. However, no changes were seen in acreage and consumed water volumes which in 90% were obtain from rivers. We have observed an increase in the incidence of disease as 56% in 2006, 71% in 2007 and 85% in 2008, respectively. The most important infectious diseases were reported Streptococcosis that incidence percent were 53%, 72% and 83%, respectively from 2006 to 2008. The results of treatment and disinfection activities have been shown an increase from 2006 to 2007 (respectively, 34.7%, 71.4% and 75%). Antibiotics were the most important drug in selected farms during survey times and their consumption was increased year to year (18.8% in 2006, 34.4% in 1386 and 52.8% in 2008). TVN and peroxide high rates were other factors of fish mortality that were related to poor storage condition and were observed usually in fish were feed to wet diet. The results have been shown an increase production regardless to health management will case fish mortality and sever economic losses.