Effects of different dietary energy levels on growth performance and sexual gonads development of Beluga (Huso huso) reared in brackish water

Culture of beluga (Huso huso) in new conditions such as inland brackish water necessitates studying nutritional requirements and effects of different diets on gonadic and somatic growth as well as physiological condition. In this research 74 beluga each 4 years old cultured in brackish water of earthen ponds in Bafgh Fisheries Research Station, were selected and distributed in 8 circular cement ponds. Feeding was done in 4 formulated diets with fixed protein level and 4 energy levels (400, 425, 450, 475kcal/l00g). Samples were biopsied at the start and the end of the experiment to determine sexuality and stage of maturation. To study gonad tissues, the hematoxylin-eosin method was used. Results indicated that somatic and gonadic growth indices were affected by diets. Somatic growth overlapped in both sexes. Sexual maturation stages were not the same in males and females and transition from stage II in males was more rapid than females. Considering the results in this study, diet treatments influenced on somatic growth in both sexes and gonadic growth in females. We conclude that somatic and especially gonadic growth in brackish water is suitable. Therefore, inland brackish water environment can be regarded suitable for beluga cultivation

Study on nutrition requirements and effect of different diets on gonadic and somatic growth of beluga (Huso huso) in new condition such as inland brackish water

Taking into consideration culture of beluga (Huso huso) in new condition such as inland brackish water, it is very important to study nutrition requirements and effect of different diets on gonadic and somatic growth as well as physiological condition. In this research 74 beluga (4 years old) cultured in brackish water earth ponds in Bafgh fisheries research station, were selected and distributed in 8 circular cement ponds. Feeding was done in 4 formulated diets with fixed protein level and 4 energy levels (400,425,450,475 kcal/100gr). Samples were biopsied in the first and the end of experiment to determine sexuality and stage of maturation. To study gonad tissues, the hematoxylin-eosin method was used. Results indicated that somatic and gonadic growth index was affected by diets. Growth somatic overlapped in both sexes. Sexual maturation stages were not the same in both males and females and transition from stage II in males was more rapid than females. Considering the results in this study, diet treatments influenced on somatic growth in both sexes and gonadic growth in females. It seems to state of somatic and especially gonadic growth in brackish water is suitable. Therefore, inland brackish water environment can be introduced as a suitable environment cultivation of beluga

Adaptation, growth and survival of tilapia (Oreochromis niloticus) in Bafgh brackish water

An experiment was conducted to evaluate the possibility of adaptation, growth and survival of Nile tilapia (Oreochromis niloticus) with 0.3g initial weight and red tilapia (Oreochromis sp.) with 0.7g initial weight in underground brackish water. Fry of Nile tilapia and red tilapia imported from Indonesia and after passing larviculture (25g) were examined separately in fiber glass tank by two replicate. Fish were fed at a restricted feeding program according to standard table during the light period. The results showed that some growth factors such as final weight, final length, daily growth rate, specific growth rate and weight gain in Nile tilapia were slightly higher than red tilapia but other factors such as survival and feed conversion rate in red tilapia were slightly higher than Nile tilapia. There were no significantly differences at 99% level among these factors. Length-weight relationship equation was w = 0.012×TL3.189 in Nile tilapia and w = 0.014×TL3.119 in red tilapia (r2 = 0.99), b value were 3.189 and 3.119 respectively in Nile and red tilapia representing isometric growth. According to the reliable growth and high survival rate (98%), it seems that both Nile and red tilapia could be good candidates for rearing in brackish water condition

Investigation of Litopenaeus vannamei culture in brackish waters of Bafgh, Yazd Province

This survey is part of the investigation on feasibility of introduction of Litopenaeus vannamei Boone, 1931 in shrimp culture industry of Iran. The objective was evaluation of the adaptation of the white leg shrimp, L. vannamei to brackish groundwaters of the Bafgh area in Yazd province. Around 120000 shrimp postlarvae (PL7 and 15) were stocked in four 0.15ha earthen ponds (17 and 23 ind/m ^(2)) in July 2005 and the culture period took about four months. Physicochemical and biological factors were studied during the culture. Shrimps were fed with commercial feed of the L. vannamei. Results showed low survival (19.2%) and growth (2-2.5g mean body weight). Based on the assessments, the limnological factors were most unfavorable elements causing the low growth in the shrimp. Concentration of K, Ca, Mg and Na Fe (II and III), different heavy metals, nitrogenous compounds, water hardness and the season and thermal periods are probably the most essential factors affecting production yield of the shrimp because of underground origin of the water. Also, the structure of ponds and drainages, presence of invasive water plants and insects may have affected the survival and growth of the shrimp as well

Biotechnics of live feed (Chironomidae) culture for using in feeding of cultured aquatics

Larvae of the chironomid midges (blood worms) are known as use full live food for cultured aquatics. There are endemic blood worms in sediments of the earthponds of Bafgh area at center of Iran. This study tended to identification of two chironomid species, Chironomus aprilinus Meigen, 1830 and Dicrotendipes sudanicus Freeman, 1959 & 1961, from Iran as a new record. Culture of blood worms was successful in glass thanks with 16h. Light, at 24-26°C temperature. Eggs were incubated after 14 days. Suitable concentration of harvesting is 1-2 egg masses (1250eggs/m2). Enrichment of earth ponds or plastic thanks including sedime is offered for culture of chironomid larvae. Collectors prepared with low cost materials are useful for collection of egg masses. May, June and July are the best time for egg collection. Large blood worms are mainly available in winter. Results of body analysis of the larvae indicated high dry matter with good quality

An investigation on possibility of nile tilapia (Oreochromis niloticus) feminization under the condition of brackish water in Bafgh

This study was aimed to investigate the effect of different doses of oral diethylstilbestrol (DES) on feminization of Nile tilapia (Oreochromis niloticus) larvae under the condition of brackish water in Bafgh fisheries research center. This Experiment was comprised of two control groups in two replicates and two experimental ones in three replicates. At the beginning of the trial, a number of 2150 larvae were randomly distributed among 10 replicates that were under treatment for 45 days. The diets in two control groups, i.e. non-treated, C1, and ethanol treated feed, C2, and the ones in two experimental groups, i.e. 200 and 400 mg DES/k of feed, E1 and E2, were administrated to 7 day post fertilization (dpf) larvae for a period of 35 days and then until day 45, the larvae were fed with ordinary feed. At the end of the trial, the gender ratio of larvae in different groups was determined by squash test in 50 randomly selected individuals from each replicate. The results showed no significant differences for gender ratios within control groups (respective male to female ratio in C1 and C2 was 47:53 and 57:43). However, the corresponding ratios within experimental ones, fed with 200 and 400 mg DES/k of feed respectively, was significantly different (P<0.05). Noteworthy that the percent of females between two experimental groups (E1 and E2) was not significantly different (70.0 and 64.7 respectively) but it was significantly different with ratios in experimental groups (P<0.05). The total body length and live body weight were determined at the begging and then at day 30 and 45, it was randomly measured in 20 larvae from each replicate. At the beginning of the experiment, the mean body weight and total length of larvae was 0.012 gram and 1.03 centimeter respectively. The respective averages at day 30 and 45 were significantly different among groups (P<0.05). Survival rate was significantly different among groups (P<0.05), being highest in E1 and E2 respectively whereas lowest in control ones (56.51 and 58.84 in C1 and C2 respectively)

Production yield of the white-leg shrimp, Litopenaeus vannamei (Boone, 1931) culture in brackish water of Yazd Province

This survey is one of the researches of Investigation on feasibility of introduction of Litopenaeus vannamei in shrimp culture industry of Iran project. The aim of this survey was study about probability of adaptation of the white-leg shrimp, L. vannamei with brackish groundwater for culture at central Iran. 120/000 postlarvae (PL7&15) were stocked in four 0.15ha earthponds (17 & 23 N/m^2), in July 2005. Culture continued for about four months. Physicochemical and biological factors were studied. Shrimps were fed with L. vannamei commercial food. Results showed low survival (19.2%) and growth (2-2.5gr mean body weight while capture). Limnological factors may be the most important agent for unfavorable culture efficiency at based on the results of measurements. Concentration of K^+ (40mg/l), Ca^+2 (370- 472mg/l), Mg^+2 (340-407mg/l), Na^+ (3450mg/l), and their proportions; Fe^+2&+3 (0.18-1.17mg/l), Zn^+2 (0.072mg/l), nitrogenous compounds especially NH_3 (3.22mg/l), water hardness (2350-2870mg/l), different heavy metals; season of stocking and daily thermal periods (2.5-12°C with 8°C mode) are probably the most essential factors effecting production yield of L. vannamei, mainly because of underground origin of the water. Also, the structure of ponds and drainages, presence of invasive water plants and insects may affect survival and growth, as well

Tilapia culture in aquaponic system

Iran is one of ten disaster countries in terms of water crisis. Also, deficit of agricultural soil is a limiting agent for development of agronomy. Moreover, production of organic crops is very important for health nutrition. Tilapia is an important commercial fish because of its fast growth, tolerance to environmental conditions and diseases, possibility of intensive culture, low costs of production and marketable flavor. Production of aquatic and agricultural crops in an aquaponic system would ask these expectations. Aquaponic system that includes combination of hydroponics and water recycling systems was examined for modulated culture of tilapia and agricultural crops at the present study. Tilapia fries with 6.2g and 5.9g mean weight and stocking density of 40/m^3 were respectively stocked in two 2.5m^3 tanks at September 2013 for 9 months. Fish culture in the two tanks tended to 17.2kg/m^3 and 19kg/m^3 fish production with 658g and 596 mean final weigth, 98% and 100% survival and 1.4 and 1.6 food conversion rate (FCR), respectively. Plants were implanted using grow beds, floating rafts and nutrient film methods. Monthly production of mint, basil, lettuce, cucumber, tomato, pepper were 1.14, 0.5-0.8, 1.32, 2.7-4, 2.03-3.4 and 1.1 kg/m^2 crops, respectively

Environment impact assessment of tilapia (Tilapia Nilotica) farming project in brachish water of Bafgh

The aim of the present study is the environmental impact assessment of tilapia (Tilapia nilotica) farming project in brackish water of Bafgh, with goals to achieve localization of technology and knowledge of tilapia fish production, employment and the possibility to controlled development in other areas. Desired range, located in northwest of Daranjir desert (Inland Salt Water Fishes Research Station, Bafgh). Total area used for the project includes three indoor hall for breeding operation, nursery (juvenile breeding) and fattening. Besides these, three 3000 m 3 available earth ponds has been considered as a potential area breeding after setting apart the quarantine. In order to achieve sustainable development of breeding this fish, impact assessment of this project development in which both environmental and social - economic effects are considered, it seems essential and project will be accomplished more confidently. So, after considering the technical characteristics of the project, the immediate, direct and indirect impact area were determined and environmental aspects of area identified. Matrix methods was utilized for the environmental impact assessment. The most important operational activities, including greenhouse structures implementation and water conveyance facilities, including excavation and embankment, channel, piping, lining of channels and their accessories including inlet and outlet valves, concrete, stone, porcelain, walling up , roof, construction of drainage network and access roads. Based on investigation, accessibility of the region, compatibility with the other land uses, lack of monuments in the area, not covered with the sensitive habitats range, the lack of permanent river flow, low quality of underground water and end up underground water flows in downstream desert and evaporated which result in impossibility of escaping introduced fish from the farm and the use of existing spaces in the first half of the year to product lead to make fewer infrastructure costs and increase revenue, are the main criteria for the sustainable development of this species culture in the area. Considering the executed studies and results of the matrix assessment construction and operation phases, it was concluded that there is no considerable destructive impacts related to the project. Therefore due to the fact that 50% of means in rows and columns of the matrix were not less than -3.1 so, we proposed execution of it with rehabilitation plans. Therefore, some strategies and plans to consider reducing the negative effects and enhance positive effects of the project, including monitoring programs, were proposed

Optimization of breeding (salinity, light regime, brood density and sex ratio) of cultured tilapia under brackish water of Bafgh, Iran

Tilapia is one of the most important cultured fish in the world. World production of tilapia is highly increased in recent decades. Tilapias can live in different aquatic ecosystems due to their reproductive strategies. On the other hand, the gap between seed supplies and farmers' demand is one of the most serious limitations for tilapia culturists. Notice about different effective agents on tilapia reproduction aspects might be useful for increasing of production and better management of tilapia hatcheries. Studies about tilapia were started in Iran from November 2008 for the first time. Some reproductive normative of cultured tilapia in brackishwater were defined. In the present study, sex ratio, stocking density, photoperiod, water salinity and replacement period of female brooders of the Nile tilapia, Oreochromis niloticus were investigated. Studied reproduction indices showed sex ratio 1:1 (F:M), stocking density 5/m3, photoperiod 12:12 (L:D), 8ppm water salinity and 10 days replacement of brooders were suitable