نشریه آبزیان دریای خزر
سال دوم شماره 4 (بهار 1397)

In order to increase of the natural products in fish farms, the survival, growth and reproduction status of many amphipod species were investigated in vitro. Seven amphipods were studied including Gammaruskomareki, Pontogammarusmaeoticus, Pontogammarusborceae, Gammarusparicrenatus, Gammaruslacustris, Obesogammarusacuminatus and Gammarusaequicauda. These species were collected from 8 locations in the Caspian Sea basin; two points in the southern Caspian Sea shore, Anzali Wetland, Miankaleh Gulf, Gorigol Wetland, Neor Lake, two springs in Hiran and Kojor regions. 150 individuals of each species were kept and similarly fed in aquariums with three replicates. The final population, length frequency and reproduction situation were studied after 100-150 days. The highest number of individuals, juvenile and the vigorous females were observed in P. maeoticus, P. borceae and Obesogammarusacuminatus. These species seems to be good candidate to use in fish farm ponds that the additional studies are also necessary.

The aim of this study, the effect of environmental parameters on biodiversity of macroinvertebrates in Shanbeh Bazar stream- Anzali international wetland during 2 seasons (spring and summer) in 2017 The sampling conducted using grab (0.06 square meter) in four stations (3 replicates) related to human activities. Totally, 1942 macroinvertebrate belong to 4 classes, 7 order and 9 families was identified at the time of sampling. The maximum abundance was related to Tubificidae (% 80.12). Shannon-Winner, Simpson, Menhenik, Margalef and Evenness were examined. According to cluster analysis, station 2 was recorded the highest Tubificidae abundance. Generally, in this study water quality was unsuitable scale using bio-indicator which represented of the need for appropriate water resource management of this area.

The effects of nutrients and light intensity fluctuations in different formulations of TMRL medium on growth and density of Chlorella vulgaris microalgae were investigated within the shortest time to obtain highest density. TMRL medium was provided with different densities of nitrogen (30, 50, and 70 gr), phosphorus (3, 5, and 7 gr), and fixed iron content (1 gr of FeCl3). The Microalgae were cultured in 2 light intensities (3500±350 lux) and (550 ± 350 lux). A total of six treatments with three replications were considered and the samples were counted 6 times within 12 days. An equal number of Chlorella vulgaris microalgae cells were injected to the treatments (15×105 cells/ml). Based on the results, the highest growth of Chlorella vulgaris obtained in the medium containing 5 g of phosphorus, 50 g of nitrogen (Urea), and 1 g of iron in light density of 3500 lux in the 12th day (p<0.05). Meanwhile, protein, fat, carbohydrate, and minerals components were 45.2, 9.5, 25.1, and 9.1 percent respectively in dry weight of the microalgae.

The production and use of phosphorus biofertilizers in agriculture began several decades ago, and the status of these fertilizers has now become widespread, that global revenues from the sale of biofertilizers in the year 2022 were estimated reach to 1.66 billion dollar that 13.9 percent of that for phosphorous biofertilizers. However, the production and consumption of phosphorous biofertilizers in the aquaculture sector has been less widely considered. The bioavailability of phosphorus for primary producers in warm-water fishponds is mainly reduced by the formation of complex with cations and organic matter. Therefore, in order to increase water soluble phosphorus, the use of phosphorus solubilizing microorganisms as a biofertilizer is pivotal. Phosphorus solubilizing microorganisms release phosphorus from insoluble phosphorus sources via production of organic acids and various enzymes. The application of phosphate biofertilizers to produce fishes reduces the use of chemical phosphorus fertilizers and produce organic products, cost effective and preserve the environment.

The study is going to survey the effect of cow dung liquid fertilizer instead of base fertilizer on propagation and growth of Daphnia in fish pond. It was performed at Mazandaran province wetlands, during spring season in 2018.The main wet land and other functional wet lands were chosen for increasing product/Unit area by promotion plan. This plan was utilized mechanization system at Sphandan rural area where is situated at Mazandaran province. The climate change was caused to decreasing input water, There fore, we can not allow to drought and should not be s elected base fertilizer. After dewatering, sampling was carried out at the primary wet land but was not found Daphnia.then,400 kg of manure fertilizer was maintained at Small pond for 24 hours and it was scattered on wet land surface during 7 days by a tanker which has a tank with pump, it was equipped at motor vichels as its capacity was 100 liter. At the end experiment, Daphnia was appeared with green belly, which is sign of fertilized environment.

The purpose of this research was to evaluate the economic and social development of fish cage culture in the southern Caspian Sea on the coast of Mazandaran province. The area with a coastline of 250 km from a depth of 20 to 100 m and 2027 km2 has the cage aquaculture capacity. The study of salmon trout Oncorhynchus mykiss growth based on the production of each cage in the southern Caspian Sea region in the second six months of the year based on the initial inputs (fish and food cost per kilogram) showed that salmon trout at primary weights (more than 35 g) although physiologically, it can be adapted to the Caspian Sea salty water, but due to the time limited it is necessary to introduce fish with weights over 200 g into the cages. Therefore, considering the potential of the aforementioned region in the coastal zone of the Caspian Sea, at least 200 fish farming sites can be constructed with the establishment of 40 cages per site, producing 160,000 tons, and the creation of employment of 1,000 direct workers and 2000 indirect workers and 2000 billions income per year and an average net profit of 40% can be expected to be 800 billion rials, which, producing part of the country's protein requirement, will create jobs, prosperity, prosperity and prosperity of the region's economy.