فهرست مطالب nima shiri

The present study intends depicting of the future sight of Iranian sturgeon relying on economic utilization. This crucial issue would be necessary to rehabilitate the vanishing stocks of these species in the Caspian Sea and Iranian caviar brand around the world. To achieve this goal, a semi-structured interview was conducted with 20 managers and experts of the specialized agricultural service company at different levels were selected by a targeted method with a maximum difference in their overview. Then, the questionnaire of designing model was implemented. Furthermore, the documents and resources related to sturgeon and caviar, the websites of the Iranian fisheries organization and the specialized agricultural services company was investigated. Afterward, the concepts were identified by analyzing the content of oral and written resources, and they were classified to two principal factors including natural stocks and aquaculture development, six main factors such as management system, enhancement the fry production, restriction of pollution releasing, accentuation on structural issues, emphasizing on scientific-technical issues and standardization, plus 73 sub- factors. In the final stage, validity and reliability of the model were confirmed and a future delineation model of these valuable stocks with emphasis on economic exploitation was designed and presented.

Diazinon is one of the highly consumed organophosphorous pesticides. It inhibits cholinesterase enzyme in animal tissues. Due to permanent residence in agricultural drainage channels، the swan mussel (Anodonta cygnea) can be considered as one of the most suitable indicators of such pollutants. At the present study، acethyle cholinesterase activity of A. cygnea was measured when exposed to various concentrations of diazinon (0، 1، 7، 15، 19، 23 mgL‐1) in different bivalve tissues، followed by comparison of short-term (first to fourth days) and long-term effects (7 to 21 days). The enzymatic activity was measured using the Elman''s method of ELISA assay. Our results indicated that there was a significant difference between cholinesterase activity levels in bivalve''s tissues at different concentrations of diazinon and exposure time. The specific activity of this enzyme in adductor muscle، digestive gland، foot muscle and gill were recorded as 27. 285، 16. 923، 2. 792 and 1. 914 nmol acethylethiocholine iodide hydrolyzed min-1mg‐1 protein، respectively. The adductor and foot muscle can be used as diazinon indicators after the exposure of A. cygnea to diazinon in environmental monitoring program. However، the gill among the other tissues، was the only one that was the appropriate tissue in determining the effects of low concentrations of diazinon (1 mg L‐1).

Common carp (Cyprinus carpio) fishes during release into the rivers estuary of the Caspian southern basin are generally exposed to a broad spectrum of agri-cultural pesticides. The objective of this study was to investigate the effects of three agricultural pesticides including Malathion، Carbaryle and Glyphosate on C. carpio in lethal level by determining LC50 96h and sub-lethal levels via cholinesterase (ChE) activity. The median lethal concentration using a standard method which is called OECD No. 203 (1992)، was measured. About 300 fingerlings with average weight of 2. 0 ± 0. 4 g were randomly selected and were then exposed to each pesticide in three treatments (0. 1، 0. 2 LC50 96h and negative control) in three replications. 5، 10 and 15 days after the test period، sampling from the head and body of fishes was carried out. The ChE activity was assayed with biochemical method described by Ellman. The LC50 96h for three glyphosate، malathion and carbaryle pesticides were obtained as 6. 75، 1. 3 and 12. 67 mg/L، respectively. The mean values of ChE for both head and body under control conditions were found 1241. 356 and 723. 103 mU/min/mg protein، respectively. Therefore، the ChE activity of head was 1. 7 times more than the body. During the test period، inhibition activitiy of ChE was significantly observed in the fishes treated by any of three components in comparison with control (p<0. 05). The ChE inhibition potential by carbaryle and glyphosate was lower than malathion as compared with control. The exposure time concentration exhibited a significant effect compared to the fishes treated by the investigated pesticide types. The used pesticide concentrations for non-target species which were ineffective and permissible according to the lethality bioassay test can lead to their enzyme responses and bio-damages.