NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2010 | Volume:3 | Issue:4|Papers Count:14

In the present study the rule of zeolit in improving environmental condition and immune potency of Mazandaran common carp (Cyprinus carpio) have investigated. For this propose the effect of zeolit with the range of 20, 40, 80 and 120 mg/l for 60 days in a completely randomized design in 3 replicate have investigated and compared with the control in growth and some physical and immune system of common carp. The fish of this research were obtained from propagation and culture fish of S. Rajaeii.Temperature, EC, Salinity, Total hardness was the same in treatment groups and control while the ion of Ammonium and Ammoniac was higher in control. The final weight (gr) of fish in treatment growth was not significantly higher than control. This situation in other parameter of growth factor was the same. In this study between zeolit treatment and control for the mean of lysozyme, Alkaline phosphatase, C3 complement, IgM, were significantly different (P<0.05). The results of the research showed that zeolit had reduced the Ammoniac and pH and increased the oxygen of the pond. In spite of the presence of difference in weight of fish in treatment and control but this difference was not significant. The use of zeolit had the effect in physiological and immunological characterestics of fish and increased the immune response in zeolity presence condition.

Blood serum testosterone (T), progesterone (P4), estradiol (E2) and cortisol concentrations were measured by radio-immunoassay (RIA) in farmed stellate sturgeon (Acipenser stellatus) female breeders during final maturation (FM) induced by GnRH (Ova-Fact III). After the detection of polar indices (PI=10-14) and hormonal survey in female breeders was carried out to induce by GnRH in 2 stage with 10mg/kg dose with interval 12 hour. Three blood samples were taken from females in timing 0, 12, 24 h after injection. Results showed there was a significant of sex steroid T, P4, E2 and cortisol levels in non-ovulated (n=2) with ovulated (n=5) fish. T, P4, E2 levels were decreased after ovulastion while cortisol increased. The data indicates that sex steroids, especially T, in farmef femal stellate sturgeon brood stock had important role in ovulation also T concenteration in non-ovulated females were significantly lower than in ovulated fish (P<0.05). The rise in cortisol level may indicate an interaction between corticosteroids and gamete maturation in farmed stellate sturgeon.

The present study was carried out the population dynamics and stock assessment of Hilsa Shad in costal of the Khuzestan province (including Abadan) using the commercial catch data. Totally, more than 9000 specimen of Hilsa Shad were measured during 2007-2008. Population parameters were estimated using FiSAT software program. The growth parameters of von Bertalanffy equation were estimated as: L∞: 42.81 and K: 0.9 and t0: -0.25. Mortality coefficients such as total mortality (i.e. Z: 3.78) and natural mortality (i.e. M: 1.37) and fishing mortality (i.e.F:2.41) were estimated.Exploitation ratio, E, was estimated to be 0.64 and these high values of E showed that the Hilsa Shad stock in the region is overexploited. Exploitation rate was estimated 0.61 and Annual total stock at the beginning of the year and the annual average standing stock and MSY were estimated 7615 ton, 1927 ton, 3642 ton respectively. The result of the study showed exploitation ratio of the Hilsa Shad stock (is reaching to the max and in order to decrease it, a serious tact should be thought.

Macrobenthos are considered as an important part of sea-bed fauna which include polycheata, creastace and mollusca. Some species are regarded as biological indicators for aquatic ecosystem because of their adaptation with environmental conditions; macro benthos is mostly inhabitants without migration. Thus, impacts of pollution in aquatic ecosystem (e.g. creeks) are served by study of community structure changes. In this study, pollution value has been assessed in Ghannam creek and a part of Mossa creek with adaption of biotic indices and physico-chemical parameters. In the present research, eight stations in Ghanam Creek (a relatively unpolluted river) and the region of Mossa Creek, around the Bandar Imam Petrochemical Company (B.I.P.C) sewage outlet were selected, and water and sediment samples were collected in two seasons: warm (September) and cold (February).Also some indices of water quality such as salinity, temperature, pH and sediment texture were measured Maximum and minimum of macro benthos density was in winter and summer respectively.Shannon's, Sympson's and Margalof’s indices were used for evaluation of macro benthic biodiversity.To access to ecological condition, the Welch Scale (1992) was applied. According to the result of the study, fourteen additional species which were relevant to six classes of benthic invertebrate of brackish and saline water existed. Maximum percentage of invertebrate occured in polycheata, bivalvia, gastropoda, decapoda, isopoda, copepoda, respectively. Lycastopsis sp had the maximum frequency among Polycheatas. Thus, the named species was determined to be considered as the topic bioindicator of water quality. In addition, the result showed that few species inhabited in the stations whose sediment was finer and their organic matter was more than of the stations located in Ghanam Creek. On the contrary, the station far from petrochemical industry (station located in Ghanam Creek) activities had more species diversity. Consequently, a significant relationship between the macrobiotic biodiversity and the percentage of organic matter and sediment texture was seen.

Esteel wetland with 138 ha extent is one of the conserved regions in Guilan Province. This study was carried out from spring 2008 to winter 2009 in order to recognize phytoplankton species of Esteel wetland and their diversity, density, abundance, and seasonal changes. According to geographical situation of Esteel wetland, 13 stations were spotted. Sampling was done with tube (P.V.C. pipe) in the middle of each season by noticing the depth of wetland. Physicochemical properties of water such as temperature, dissolved oxygen, pH, nitrite, nitrate, ammonium, phosphate, and EC in 5 stations were measured in each sampling. In this study, totally 10 phyla and 42 genus of phytoplankton were identified. From these, 6 genus belong to Cyanophyta, 17 genus belong to Chlorophyta, 1 genus belongs to Chrysophyta, 8 genus belong to Bacillariophyta, 4 genus belong to Euglenaophyta, 1 genus belongs to Heterokontophyta, 1 genus belongs to Cryptophyta, 1 genus belongs to Phyrrophyta, 2 genus belong to Charophyta, and 1 genus belongs to Cyanobacteria phylum. The average annual density of phytoplankton in this lagoon was 12387 cell/ml1-. Cyanophyta with the density of 283274 cell/ml1- and the abundance of 93.34% and Cyanobacteria with the density of 3 cell/ml1- and the abundance of 0.001%, respectively had the most and the least annual phytoplanktonic density and abundance that had significant differences (P<0.05) with other phyla. Seasonal changes of these planktons also showed that summer with 10 phylum and 25 genus of phytoplankton and autumn with 5 phylum and 10 genus phytoplankton had the most and the least diversity, respectively. Also summer with the density of 46801 cell/ml1- and winter with the density of 14 cell/ml1- had the most and the least annual density of phytoplankton which had significant difference (P<0.05) with other seasons.

Considering increase in production of earth ponds in brackish water condition, this research carried out at bafgh fisheries research station to improve efficiency and production of brackish water cultural earth ponds of rainbow trout (Oncorhynchus mykiss). This study was performed in four 0.5 ha earth ponds in two treatments with two replications. Each treatment included two earth ponds so that fish farmed in two culture mediums consisting open medium and %20 enclosure medium of pond (pen medium). For this purpose 20% of earth pond’s space separated via a fixed net wall with 15mm in mesh. In this research some main growth equations (WG, ADG, FCR, SGR, FE, CF) and economical factors were studied. Data were analyzed using SPSS software, Toki, Dankan, Dant analysis and also descriptive statistics. The significant differences were determined in %5 level. Since there was a connection between pen medium with free one, no signs based upon disturbance observed in measured environmental factors in this space. Statistical results indicated a significant increase in %WG, %FE, %SGR, %CF and final biomass in pen medium treatment. According to economic results, this treatment also differed significantly from open medium treatment about ratio of marketable size production and net income so that yield quantity and production income increased. Therefore, through pen culture in 0.5 ha earth ponds and likely larger ones, utility and production of farm improve and can be a good approach for farmers in order to better exploitation of possibilities and facilities.

Anodonta cygnea (linea, 1876) is one of the most important benthic invertebrate of streams, ponds and wetlands of Pasikhan river catchment area. This study was conducted on 89 specimens of A. cygnea from 3 streams of pasikhan river watershed during July to September 2004 in order to study growth and age structure. The population comprised four age groups. The 3+ age group was dominant in the studied population. The lowest and greatest values for the length, width, height, total weight, wet soft tissue weight, dry soft tissue weight and shell weight of A. cygnea were 53.5-115.5mm, 15.6-46.2mm, 27.2-59.1mm, 11.23-127.02g, 8.74-71.73g, 0.47-5g, 2.49-36.73g, respectively, and their values increased with age. The frequency of two length classes 83-93 and 93-103mm were the highest. Instantaneous growth rates increased with age. The mean value of condition factor was 8.99±2.57 which increased to 3+age group and then decreased in 4+ age group. Shell weight was 27.15±9.7% total weight and its value increased with age. Shell dimensions were a suitable criteria for the biomass A. cygnea when applied to total weight and wet soft tissue weight (r2 values of 89-96 percent), but not to dry soft tissue weight (r2 values of 59-60 percent). The slope (b) (3.0923±0.089) of the shell length-total weight regression indicated isometric growth. A highly significant linear regression of height and width over length and of height over width as well as a highly significant nonlinear regression between shell length and mussel age were found.

The survey acute toxicity of Chloropyrifos and Diazinon toxins that use large quantity in agriculture fields specific in Golestan province studied on Rutilus rutilus caspicus fingerlings (1-3g) in this research, aim to determine the 50% lethal concentration (LC50) in 96 hours. These experiments carried out in static condition and based on TRC, 1984 standard method in 4 days, and controlled of the effective water physico - chemical factors that having ranges pH =7-8.2, DH=205 mg /l (CaCO3), DO=7mg/l and Temp=26±oC .During experiments reaction and behaviour of the fingerlings exposure of toxin seen carefully. Early experiments for find of mortality range with released in to a 20lit aquarium (10 fingerling of 1-3g in aquvarium) and continous aeration. Finally experiments with 5 treatments, 3 repetitions and 1 blank. On the base of obtained results by Probit program version 1.5 LC50 value of Chloropyrifos and Diazinon in 96 hours were 0.016 and 12.81 mg/l on Rutilus rutilus caspicus respectively, and also Mac (Maximum allowable concentration) value of this toxins were determined 0.0016 and 1.281 mg/l for Rutilus rutilus caspicus respectively.

Parastromateus niger is one of the most important species which has been studied in the project of “stock assessment of demersal resources by swept-area method in the Oman sea (1999-2000). 4 research cruises were conducted by R/V Ferdows-1. The area chosen for the study was from Meidani (58o55' E) to Gwatre Bay (61o30' E) having depths of 10 to 100m. The studied area of 1164 n.sq.mil. Was divided into 5 sub regions (A, B, C, D & E) each covering 30Minutes width. Each region was divided into 4-depth stratum: 10-20, 20-30, 30-50, and 50-100 meters. In each cruise, sampling was carried out for more than 90 stations using a bottom trawler. The seasonal and annual biomass for each region and stratum was estimated. The average annual biomass for the whole area was calculated as 616.37 tons and for each stratum of 10-20, 20-30, 30-50, and 50-100 m the estimation was 276.62, 105, 66.5, and 168.27 tons respectively. The maximum biomass was located in the depth of 10-20 m while the minimum was found in the depth of 30-50 meters. The annual average biomass for different regions of A, B, C, D and E was calculated as 75.27, 48.91, 224.03, 97.64, and 170.53 tons respectively. The fork length and total weight of 1258 specimens of p. niger were measured; the fork length ranged from 14.5 to 58.5 centimeters. Comparison of distribution patterns indicated that the p. niger inhabits mainly in front of estuary of Galak, Gordim and the head of Pozm. The seasonal parabolic equations of length and weight relationship were studied. In this regard, there was no significant difference among seasonal b-value. According to the calculated CPUA, the result indicated that in each season at least in one sampling station it was higher than the minimum base of concentrated level. The result showed that there is a schooling stock of this species in the region.

This study was done on 692 specimens of Ship Sturgeon (Acipenser nudiventris) in International Sturgeon Research Institute Dr Dadman and Sturgeons rearing and propagation Shahid Beheshti hatchery from June to October 2007. A number of 23 specimens were identified from viewpoint of external lesions and samples were studied for bacterial agent's isolations. The observation showed the most content of lesions were related to scutes with abundance of 78.3%, skin (39.1%) and finally fin (8.7%). In bacteriological experiments, Aeromonas cavia (23.5%) and Acipenser lowffii (23.5%) had the most abundance (from total bacteria) and Pseudomonas flurescens and Enterobacter(sp) 2.9% had the least frequency. Also, Pseudomonas putida (14.7%), Aeromonas sobria (11.8%), Acetinobacter calcoaceticus (8.9%), Klebsiella oxytoca (5.9%) and Aeromonas (sp) with abundance 5.9% were come next. A.cavia in lesions of skin (25.1%) and scute (26.4%) had the most aboundance. In fin; A. lowffii (75%) had the most abundance. In this survey, all isolated bacteria were gram negative. With regard to existence of bacteria in lesions, the reason can be the water source in culture. So, health management is mandatory to keep water in good quality and suitable density and take a good care of it in order to control the bacterial agent.

Caspian salmon (Salmo trutta caspius) is one of the economically valuable species in the Caspian Sea. Artificial propagation and production of larvae are of the main problems in the early culture of this species. For this target, in the propagation season in 2009, the effect of reproductive performance of female broods on opposition reproduction efficiency in Caspian salmon was studied. For this study, 3 groups of female broods (4, 5 and 6 years old) were fertilized individually by 9 male fish. The results showed that the 6-year-old females had the maximum mean of body weight before breeding (2150.0±86.6 gr), after breeding (1840.0±2.92 gr), total length (59±2 cm), eggs weight (255.0±30.51 gr), diameter ovules (5.37±0.058 mm), and fecundity rate (3060±366.15 eggs).While the highest average number of ovules in each gram of body weight (16.33±0.58) and relative fecundity (2.08±0.12) belonged to the 4-year-old females. The study showed a significant difference in the mean of fertilization & survival rate until the complete absorption of yolk sack satge in the treatment group.The present study showed that the produced eggs out of fertilization of the 6-year-old females by male fish will have the maximum average rate in fertilization percentage (97.5%), survival percentage (until eyeing) (92%), hatching percentage (93%), and survival until the absorption of yolk sack stage(94.5%).

Beluga (Huso huso) is the biggest sturgeon fish in Caspian Sea. Artificial propagation of Beluga has significantly emerged in recent years due to the prolonged maturation age and destroied breeding grounds .One of the artificial propagation stage is removing egg adhesiveness by using clay suspension. It can be done by utilizing some water to make 10 percent clay suspension, and washing the fertilized eggs for 30- 45 minutes to remove the adhesiveness. This process is time-taking while Tanoan can be a good replacement for it. 3 brooder females of Beluga used in propagation season 2008. After breeding and artificial propagation, each brood stock divided into 8 portions: treatment (0.625gr Tanon in 1.25 liter water) and control (10 percent clay suspension); each group was washed with 4 replicate. According to the results, washing time for Tanoan is 1 minute and 30 seconds but for clay is 45 minute. The fertilization rate in washed eggs in Gastrula stage by Tanoan and clay suspension are 78.7 and 71.6 percent respectively. Fungal infected percent are 3.40 and 8.70 respectively, hatching rate 77.32 and 69.57, and larvae survival rates to yolk sac resumption are 96.39 and 92.38 respectively. The replacement of Tanoan would save time and could reduce the possible expenses in the process and also a few number of fertilize eggs re-exposed to the possible threat of being damaged. It will also increase the larvae survival rates in propagation.