5 research outputs found

    The growth, survival rate and reproductive characteristics of Artemia urmiana fed by Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. as feeding microalgae

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    This study was performed to compare the efficiency of six microalgae namely Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. on the growth, survival rate and reproduction efficacy in Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to the standard method. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. A highly significant difference (p<0.01) were found among three microalgae in terms of length growth, survival rates and reproduction characteristics in A. urmiana. In spite of higher length growth of A.urmiana fed on N. oculata than A. urmiana fed by T. suecica but survival and reproduction in the latter was better than the first treatment. In general, D. tertiolecta was more efficient than other microalgae examined in the present study on A. urmiana concerning not only to growth and survival but also to reproduction mode. So, it is preferred to feed A. urmiana

    The Effects of Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata as Food on the Growth, Survival and Reproductive Characteristics of Artemia urmiana

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    Abstract Artemia is the most widespread live food used in the production of different stages of many aquaculture organisms. It is a non-selective filter feeding organism. Generally, microalgae are the most favorable feeds for Artemia, particularly when the algal species have suitable size, digestibility and nutrient values. This study was performed to compare the efficiency of three microalgae namely Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata for growth, survival and reproduction efficiency of Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to standard methods. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. The results indicated a significant difference (P&lt;0.01) among three microalgae in terms of growth, survival rates and reproduction characteristics in A.urmiana. In spite of higher length growth of A.urmiana fed on N.oculata than T.suecica but survival and reproduction in A.urmiana fed on T.suecica was better than the first treatment. In general, D.tertiolecta was more efficient than T.suecica and N.oculata on A.urmiana, hence, it is preferred for feeding A.urmiana

    Effects of environmental factors on the growth and development of Astacous leptodactylous in Aras River and its Reservoir

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    In order to study plankton population composition and species diversity in different regions of Aras Rivers and the evident reservoir sampling was performed monthly from determined sampling sites from April 2007 to March 2008. Sampling was conducted in Reservoir Lake by a PVC pipe with 2.25 m length and 5 cm diameter by columnar method. Besides, in more dipper (>5 m) sites, sampling conducted from bottom to surface with 1-m intervals (layer sampling) by a 2-liter Ruttner type sampler. In river due to water flow sampling was conducted by a scaled measure. Phytoplankton sampling was performed by 1-liter bottles. Zooplankton was sampled by filtering of 30 L through 55- micron plankton net. These samples were then transferred into bottles and sampling date and the name of station were attached on the bottles. Then, the samples were fixed immediately and transported to laboratory. It should be mentioned some physical parameters were determined in situ. Also, a 1liter and another 2-liter water were collected to determine chlorophyll a and chemical factors respectively. Samples were preserved in dark and cold place for a week. The upper layers (without phytoplankton) were removed and the lower layer (with phytoplankton) was sampled into 5-ml chambers. The enumeration and identification was performed by a Nikon TS100 inverted microscope with ×400 (Phytoplankton) and ×200 (Zooplankton) magnification according to Utermohl (1958) method. About 50 fields were enumerated for each sample. The comparison of physicochemical and biological factors with standard criterion indicated that the presence of a fertile plain, agricultural growth, drought and higher water demand in recent years, as well as, higher population density, the Nakhjavan city location and sewage water flows into the Aras reservoir, the lake is going to be an eutroph lake. Sampling of crayfish was performed from 5 sampling sites seasonally. Aras reservoir freshwater crayfish biomass was sampled in 1391, by putting 100 funnel-shaped nets. At each site one row nets composed of 20 nets were put by rocks, connecting robe and boat. Twenty four hours later, total freshwater cray fish was sampled (at least 300 crayfish was randomly sampled from each site). The samples were transported to laboratory and their sex, sex percentage, biometric characteristics including length, weight were recorded. Length and weight groups were estimated totally and for males and females in each season. The average total length and weight were 106.43 ± 7.94 mm and 35.81 ± 10.86 gr respectively which both are lower than West-Azarbaijan fisheries criterion. In this study only 18.99 percent contained a length higher than exporting level (120 mm). Yet, only 16.46 percent of harvesting had higher than 50 g (exporting level). With regard to data, freshwater shrimp (Astacus leptodactylus) in Aras dam reservoir stock has reduced. In general, male-female ratio was high. The comparison of growth equations confirms that males had higher weights than equal females. In recent years, the freshwater crayfish harvesting has been declined due to increased harvesting and over loading of nutrients into the lake

    The Comparison of the culture operation of Artemia franciscana and parthenogenetic species on the sidelines of Qom Salt Lake

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    Qom Province with an area of 11,238 km^2 , surrounds about 0.68%of the country area and almost situated in the center of the country and enjoys a hot and dry climate . Because of the unique flora and fauna of the region especially the salt pools - hoze- Sultan and salt lakes enjoys a certain ecosystem in the country. Research has done in different parts of Iran and Qom province regarding the Artemia culture in salt lands that showed a great potential in the country and Qom province. The aim of this study that was held in order of Qom fisheries institute and environmental protection organization of that province and scientific leadership of Iranian Artemia Research Center, was the culture of Qom native Artemia and Artemia franciscana ( foreign species ) across Qom salt lake and determining the prevalence of cultured species in this region for this purpose, site selection and climatic and topographic data collection was held at 5 regions of Qom province. This regions were included margins of salt lake, and hoze sultan, shams abad drainage, railway station, and freshwater culture farm at the north east of Qom salt lake. margins of salt lake, and hoze sultan, were suitable for Artemia investment due to suitable climate and vast area, but they had problems in terms of technical facilities and access to areas . Also, the rail way station and plantation industry had dehydration problems. Therefore, after reviewing the field of agricultural water taken along the 45 km of Kashan and Qom Salt Lake were selected for the project because of the salty ecosystem similar to the lake, presence of salt water drainages downstream of the farm , technical facilities and a large area , soil texture and easy access to the area . For this purpose, six pools with 50 square meters near the reservoir pool available were constructed and 70 g native Artemia cysts of Qom and 23/3 g cysts of Artemia franciscana were hatched in Zooks of 10 liters for each pool ea of 50 square meters under standard condition (salinity 35 ppt pH =8, light lux 2000 and temperature 28°C). By calculating the useful volume of water for culture (112 cubic meters) and Hatching efficiency for native Artemia of Qom (40,000) and Artemia franciscana (120,000), the number of 25 nauplii per liter equal to the 2.8 million nauplii were released to each pool with size 4 × 12 m and high slope with area of 50 meter in the floor and 273 meters in the surface . Non- biological and biological studies, including algae and water analysis and population assessments were performed regularly in pools every 2 weeks. the culture period were from July to mid- October, 2009 for a period of 3/5 months. The results of algal study revealed more abundance of Cholestrium, Navicula, Nitzshia algae during culture period (105 days), that Amphora, etraselmis, Cymbella, Senedesmus, Dscillatoria, Gomphonema genera were observed, too. The results of water parameters analysis revealed that they should preserve at salinity 40–50 ppt, pH 8, water hardness 7000- 9000 mg. the results of population assessment showed a larger amounts of female broods of Qom Artemia at days 15,30 and 90 of culture with average number of 120.3, 68.8 and 29.5 per liter, respectively, comparing to Artemia franciscana with average number of 28.8, 17.5 and 7.7 per liter that was significant (p<0.05). The results indicated the greater development and adaptation of native Artemia of Qom at the culture ecosystem of Qom (Kesht va Sanaat Ab Shirin farm at the northeast of Qom salt lake). Harvesting of Artemia biomass of native Qom with the amount of 30 kg/100m^2 showed the production of native Artemia is relatively economic and during culture period (105 days) the mean cyst production for native Qom Artemia and Artemia franciscana were 193 and 123.5 individuals/liter, respectively. It can be concluded that native Qom Artemia enjoys a greater adaptation in growth and development with the arid ecosystem of the region and can be used as a valuable biologic stock in culturing purposes and developing native Artemia strains of the country and investments in construction of Artemia culture pilots in salt areas situated at Qom salt lake

    Determination of permitable distance between coldwater culture farms with common water supply in pirdanan river of West Azarbaijan

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    Regarding the increase in world population and decrease in fish stock, there is an urgent need to aquaculture practices. Coldwater fish culture is aiming at production and providing a part of protein needs of the country and a way reaching to self- sufficiency and preserve the water resources. Recently, multi- purpose use of water resources potential and especially the rivers of west Azarbaijan, for example, construction of fish farms at upstream of permanent rivers in order to make optimum use of the resources and the increase in employment has been considered . The waste water of these pools is usually discharged into the rivers. Regarding to increased production per unit area due to water resources and cold water fish culture restrictions to use regional facilities and fish farm construction, it is nessacery to determine limits between 2 farms. In this study with the goal of evaluation of the impacts of trout farm effluents on water quality parameters of Pirdanan River, the factors of water current, temperature, pH, EC, TDS, TSS, DO, BOD_5, NH_3, N-NO_2, N-NO_3, TP P-PO_4 according to standard methods were determined montly during 2014-2015 . Sampling sites were entrance, exit of Maroofi trout farm and the distances of 700, 1400, 2100 and 2800 m after the farm exit. Seasonal sampling of macro invertebrates from mentioned sites was conducted using stone leaching. The family and genus of macro invertebrates were identified using identification keys and abundance of macro invertebrate phylums for each site was determined. The results revealed that the values for water current, EC, TDS, TSS, N-NO_3 were significant. the values of water temperature, BOD5, TDS, TSS, N-NO^3- , N-NO^2-, NH_3, P-PO^4- , NH4+, N-NH3 were increased in site 2 compare to site 1 in all months and gradually in the river and its self- purification were decreased. In this study, 4 phylums, 4 classes, 7orders and 14 families of macroinvertbrates were identified from Pirdanan River. Ephemeroptera had the highest abundance in site 4; while Diptera had the highest abundance in site 2 (exit). Regarding that most of Diptera macro invertebrates were from Chironomidae, so it can be concluded that site 2 was the most pollutant site and sites 5 and 6 were more suitable condition. Therefore, considering the physic- chemical factors and macro inverteberates indices, 2100 m from entrance, (site 5) is recommended compliance with veterinary organization rules and other conditions of aquatic engineering, environmental and water operation standards
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