Document Type : Research Paper
Authors
1
PhD in Aquaculture, Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, Iran.
2
Professor, Department of Fisheries, Faculty of Natural Resources, Tehran University, Karaj, Iran.
3
Associate Professor, Department of Fisheries, Faculty of Natural Resources, Tehran University, Karaj, Iran.
Abstract
A completely randomized experimental design in triplicates was conducted to evaluate the effects of different levels of nitrogen with the constant level of carbon and phosphorous on production of warm water fish in Chapakrod fish farm in Joybar. The treatments were use of three levels of C: N: P, respectively, 1: 5.5: 88.6 (T1) 1: 7.5: 88.6 (T2) and 1: 9.5: 6.88 (T3). The mixed chemical fertilizers and organic manures consisted of chicken, cattle feces, vermi-compost, phosphate and urea mixed together to get different levels of CNP. The effect of different concentrations of nitrogen on phytoplankton abundance and chlorophyll, were investigated as well. At the end of experiment, the highest number of phytoplankton, chlorophyll, relative growth indices were significantly different (P<0.05) among treatments. The highest primary production and phytoplankton number was recorded in treatment T2 with rate of 638 mg/m3/hr and 438,750 per/ml, respectively. The least rates of primary production and phytoplankton were recorded in T1. The mean individual fish weight was higher in T2 for all chines fish carp at the end of the experiment. This rate for silver carp attained to 40/875 gr at the end of the experiment. The most prominent of phytoplankton were recorded among treatments included: Ankyra, chlorella, Pedyastrum, Tetrastrum, spirogyra, Navikula, diatoms, filamentous algae and the most benthos and zeoplanktons were included: rotifers, Daphnia, copepoda, ceratopogonidae, and tippulidae.
Keywords
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