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This investigation has been carried out to complement the previous related study, aiming the Possibility of culturing white leg shrimp (L.vannamei) at higher densities of 50, 70 and 90 indiviuals/m^2. After 122 days rearing period, the highest mean weight of shrimp obtained at density of 50 indiviuals/m^2 (16.91± 2.43 g) with no significant difference with that obtained at 90 indiviuals/m^2 density (P≤ 0.05). Mean weight gain of the shrimp in the 70 indiviuals/m^2 density (14.35 ± 2.17g) was significantly lower than that at other densities (P≤0.05). Results showed no significant (P>0.05) difference between survival rates, FCR and PER in the different treatments. The highest yield of 14008 kg/ha with the mean weight of 19.43 g/shrimp was obtained at the density of 90 indiviuals /m^2. According to the results of the present study it could be concluded that 90 indiviuals /m^2 could be adapted as suitable density for economically feasible culture of L.vannamei in earthen ponds in Chowibdeh site if the appropriate conditions are provided.

According to the white spot disease during 2002 until 2005 and the damages caused by the disease to the farmers a new species L.vannamei were introduced to the farming region of Abadan Choebdeh from 2006. Hight mortality occurred in Khuzestan province farms in 2007 and 2008 again. Probably viral agent was transferred to native shrimps or other aquatic animals, therefore it is very important that presence of viruses in local aquatic animals and its vectors detected. Detection of WSSV, TSVand IHHNV in aquatic animal from Khuzestan costal region imphasis to wild shrimp and craps is the main objectives of this study. So samples were taken from 10 active farms twice a week and 100 postlarves from 3 active breeding center befor stocking. Samples for viral detection were studied by molecular and histopathology asseys. Results was shown presence of the White spot virus in cultured and wild shrimp and TSV infection in only two cultured shrimps but there was negative result for IHHN virus. To study the pathogenesis of white spot virus isolated from wild and farmed shrimps, exposure method was used. Results of challenge showed that WSSV can be transmited from diseased cultured and wild shrimp to cultured shrimp. Mean mortality percent in the treatment that fed with infected wild shrimp was 38.33±10.4 and treatment that fed with infected cultured shrimp 61.66±7.63 and in the positive control treatment was 87.5±3.5.

This study was carried out to investigate the optimum stocking density for white leg shrimp (Litopenaeus vannamei) in earthen ponds in Choweibdeh shrimp site Abadan southwest Iran. Six 0.5 ha. Earthen ponds were applied to survey three stocking density of this shrimp (30, 45 and 60 indviduals/m^2) with two replicates each. 15 days old postlarvae (PL15) with mean weight of 0.021 g were reared in the experimental ponds for 60 days. Results showed no significant difference (P>0.05 ) between the tested stocking densities in terms of growth (weight gain, length increment), specific growth rate (SG ), weekly growth rate, survival rate, food conversion ratio (FCR ) and protein efficiency rate (PER). Nevertheless best results were obtained in the stocking density with 30 ind./m^2 . Yield was increased by increasing the stocking density and the highest yield was obtained in the density of 60 ind./m^2 with significant difference with two other densities. Ultimately, according to the findings of the present study, stocking density of 60 ind./m^2 can be suggested as an acceptable density to be applied for white leg prawn in the region.

Following to introduce Vannamei shrimp (Litopenaeus vannamei) into Iran aquaculture industries by fisheries organization its postlarvae were successfully reared in ponds in Bushehr and Choebdeh in Khuzestan. Due to activity of Shrimp site and importance of input and output water quality, this study was done in 11 stations including: two stations in Bahmanshir river, two station in C4 and C5 irrigation canals, six staions in active farms along C4 cannel (Yonesi, Mosavei and Salman Zadeh), and C5 cannel (Mohamadi, Khairi and Ashraf Por) and one staion in output draing were selected. Sampling were carried out from May2009 befor beginning stocking to harvest time in October 2009. Physico- chemical parameters and plankton sampled biweekly and benthic animals and heavy metals were sampled monthly. Some parameters such as pH and temperature by using portable multy parameters and others. Analyzed with standard methods. Heavy metals were measured by plarography method (797 Vamtro). Plankton and benthos samples were studied only in Bahmanshir station. According to results the maximum values for DO (11.1 ppm) PO4 (1.86 ppm) NO3 (8.4 ppm) and TSS (4992 ppm), pH (8.4) NO2 (0.18 ppm) BOD5 (9.06 ppm) were measured. In comparison to aquaculture water quality standards except for TSS in river stations others are located in allowable range. We didn’t observed any main changes in water quality from river to output drainage. The results of biotic parameters in river stations showed that diatoms were the most group of phytoplanktons. Zooplankton groups were Copepods, Rotifera and Protozoa. Tintinids and Nematoda larvae were the most abundant zooplankton. Benthic animals were included nine crustacean species and two annelid species. Isopods with 52% were the most and ant group.

The introduction of L. vannamei to Iran from Hawaii was initiated when high mortality occurred in shrimp farms of Abadan in 2002 than in Bushehr during summer of 2004. Inspection of L. vannamei for infectious agents (Bacteria , virus , fungi and parasite ) , determine total plate count and total vibrio in Bahmanshir Rivers, shrimps and farms water , examination physicochemical factors of farms water , Identification of carriers of wssv in wild shrimp and crabs , the main objectives of this study , which was held in 2007 . 540 shrimp samples (pl12 pl15) and subadults were collected from different shrimp farms in khouzestan province and then check for identity bacteria, fungi and parasite. Also 280 samples of L. vannamei , wild shrimps ( Metapenaeus af inis , Exopalaemon styliferus ) and crabs (Grapsus sp .and Sesarma sp. ) were Collected from Bahmanshir river for virology studies by PCR procedure (Iq2000 kit WSSV , IHHNV , TSV ) . 120 samples of L. vannamei for histopathology had been collected randomly and preserved in Davidson’s fixation and then transferred to 75% ethyl alcohol for storage. (Hepatopancreas gills). Physicochemical parameters of water in culture ponds comprising of pH DO, BOD, NO_3, NO_2, salinity. Total. Hardness and NH3 were measured all over culture period for 340 times. Finally it has been detected 10 genus and species of bacteria consisting of V . alginolyticus, V. parahaemolyticus, V. proteolyticus , plesiomonas shigelloides ; 6 genus and species of fungi specially Aspergilus niger , Asp.fumigatus and Asp.flavus and two genus of parasites vorticella sp. And Zoothamnium sp. were isolated. Crab (Sesarma sp.) were tested by using Iq2000 diagnostic kit for WSSV that positive for WSSV. There was a positive result (three viruses TSV, IHHNV and WSSV) for postlarvae and subadults of L.vannamei by using Iq2000 kit and IFRO kit (Internal kit). Histopathological studies have shown inclusion bodies of TSV, WSSV, IHHNV, MBV and HPV in various tissues. Results demonstrated the mean of vibrio count (0. 01×103 - 1.96 ×103) and tolal plate count (0 .21 ×103 - 14.25 ×10 3). physicochemical parameters of water were measured as follows : salinity (12.3 22.5 ppt ).BOD5 ( 1.98 10.21 ppm ) , DO (3.17 11.25 ppm ) , NH3(0.02 3.45 ppm ) and temperature (20 31. 5 c) . Keywords: L.vannamei, bacteria, virus, fungi, parasite Histo pathology - physicochemical parameters of water- Abadan khouzestan province.

Possibility of rearing silver bream (Sparidentex hasta) in the earthen pond was experimented using 2 types of available artificial trout feed (FFT and GFT1). The experiment was carried out in 2 phases in Shahid-Kiani Extension Shrimp Farm in Chowibdeh Shrimp Site-Abadan Southern Iran, and earthen ponds with 0.25 ha. Area were used for both phases of the study. Juvenile fish of 3.2 g initial weight with the density of 9324 ind./ha. Were stocked for 196 days in the first phase. The initial weight, stocking density and rearing period of the fish in the second phase were 108.60 g, 9800 ind./ha. And 237 days respectively. Maximum amount of WG, FCR, PER and SVR of the fish in the first phase of the study were 100.12 g, more than 6, 0.38 and 55.32% respectively. WG and SR of the fish in the second phase respectively were 417 g and 20.74%. The Salinity of pond water was in the range between 9 and 22 ppt, and the water temperature was between 8.3 ֯C (mid December morning) and 34.8 ֯C (early Sep.....

This study has been carried out to evaluate the possibility to culture shanak (yellow fin seabream: Acanthopagrus latus) fish in the ground pond. The study including two experiments. In the first experiment two commercial available feeds (403 as shrimp food and F.F.T as trout food both produced by Chineh company) are used to evaluate the growth performance of the bream Juvenile produced artificially in the Bandar Imam Mariculture Research Stationin weghing 2.72- 3.54 g. To perform the first experiment 6 ground ponds each with 0.25 ha area are used as replicates 3 ponds randomly allocated to each food. 5000 in dividual juvenile fishes are stocked in each pond. After 116 days rearing period well growth performances are achieved for both foods with no significant difference (P 0.05) between them, although better growth performances are observed for F.F.T food. The final weight (WE), SVR ,FCR and SGR of shanak for F.F.T food respectively were 23.29 ± 11.14, 95.98% ±0.78, 1.39 ±0.26 and 3.47±0.23 where for 403 food were 22.08±9.95 , 89.67%±8.75 , 1.53±0.12 and 3.25±0.33 respectively. In the second experiment in which only trout food was used the target was to examine the growth parameters of shanak juvenile in a full rearing period (198 days) in the ground pond. Juvenile fishes with 36.53 g were used with same methods adopted for the first experiment. The final weight of 206.3 g is achieved by 89.35% SVR and 1.92 of FCR. Results of this experiment showed that the growth quickly improved with fast rate along with the increment of temperature and salinity up to 25ºC and 14 ppt respectively. There after by the raising the temperature and salinity more than 25 ºC and 14ppt respectively the growth reduced.

For assessing management efficiency in shrimp hatcheries of Choebdeh (Abadan), we surveyed the physico-chemical properties of water in two culture periods during the years 2001-2002. Different physical and chemical factors were measured in hatcheries under Thai and Philippine management methods. We measured factors such as salinity (17.9-35.3 ppt), BOD5 (6.12-8.72 ppm), DO (10.02-13.7 ppm), COD (4-98.9 ppm), NH3 (0-811A ppb), NO2 (10421 ppb), pH (8.04 -8.68), Turbidity (1-33 NTU), Ca (400.4-620.6 ppm), Mg (1104-1968 ppm), total hardness (6000-9400 ppm) and water temperature {25.4-32.4°C) while no amount of SH2 was found in the water samples. The results of this survey were compared with standard levels and safe ranges for aquaculture activities. Most factors were in standard range with only NH3 and NO2 showing a slight excess in some cases. An ANOVA test showed significant differences in levels of oxygen and COD of the tanks at different sampling times.

This survey was performed in order to investigation of parasites in different tissues of cultured shrimp and survey of intensity and incidence of these parasites in different tissues of shrimp. In this survey 145 shrimp belonged to Penaeus monodon and 97 shrimp belonged to P. indicus were reviewed. Epicommensal protozoa from gills and appendages by wet smear, stomach and hepatopancreas and intestine by stereomicroscope, crashed muscle and digested muscle and also, crashing of intestine for digestive protozoa were reviewed. The most intensity and incidence were belonged to Epistylis, Zoothamnium and Vorticella, respectively. In relation to metazoan parasites, there were no observation of worm parasites, such as trematodes, nematodes, cestodes and digestive protozoa such as gregarine among the cultured shrimp. All shrimp are susceptible to fouling by epicommensal protozoa. These organisms are naturally present on the bodies of cultured shrimp and their intensity and incidence can be related to the environmental condition. According to life cycle of metazoa and digestive protozoa (Johnson, 1989), absence of these parasites among cultured shrimp can be due to lack of intermediate hosts and consequently lack of completion of life cycle of these parasites in the cultured environments and consumption of prepared (inert) food.

Gregarines are protozoa that occur within the digestive tract and tissues of various invertebrate animals such as shrimp. In this survey 15 marine broodstocks of Penaeus indicus from Jask area and 119 cultured shrimps from cultured farms were supplied and carried to laboratory. According to life cycle of gregarine, (Johnson, 1989) it is assumed that presence of protozoan gregarine among broodstock shrimps can be due to consumption of natural food and existance of intermediate hosts and as a result to be completion of life cycle of these protozoan in natural conditions. On the other hand absence of these parasites among cultured shrimp can be due to consumption of prepared (inert) food and lack of completion of alternate hosts and intermediate hosts and consequently lack of completion of life cycle of these parasites in the cultured condition.

The development of the commercial culture of penaeid shrimps has been accompanied by the occurrence of infectious and noninfectious diseases. The most important penaeid diseases are caused by organisms that are part of the normal microflora of penaeids. In 1998, the samples were collected from five farms in Ghofase area (Ahadan) 2-5 ponds in each farm. The shrimps of these ponds were preserved in full hygienic conditions, from each pond, at least 5 samples were collected and then transferred to the Aquatic Diseases Laboratory of Khouzestan Fisheries Research Center. The main tissues of Gill, Hemolymph, Hepatopancreas and cuticle of live-shrimps were studied in the laboratory. In this research, a total of 40 fungal species were isolated from different tissues with high abundance in Hepatopancrease (19 species) and Hemolymph (12 species). Aspergillus niger was identified as the most abundant species.