stressful Chemical Factors in the Water Bodies of Parishan Lake

This research was carried out by Fishery Research Center of Parsian Gulf cooperation from July 1995 to Jun 1996 in Parishan lake situated in Fars province, and during that environmental chemical analysis such as oxygen, pH, free ammonia, nitrite, and hydrogen sulfide were investigated which results were as fallows respectivery : 0.33 - 7.58 ^mg/_lit, 8.47 - 9.41, 6 - 409 ^µgr/_lit Nitrogen, 2-319 ^µgr/_lit Nitrogen and 0 – 4551 ^µgr/_lit .In Parishan lake ecosystem the average pH in Autumn was more than 9, which this pH had some effects directly and indirectly on growth and health of fishes. The average of morning oxygen concentration was acceptable just in summer and early Autumn and during the remaining of the year it was about 1 or less than 1 ^mg/_lit. The average of free ammonia was also more than acceptable range most of the time during the year. Just in April there was not any tension. From free ammonia and in other times concentration of this gas was high and probably influence the growth of aquatics. The results showed that Parishan lake ecosystem most of the time was influenced by unfavorable Chemical factors and so prior to fishery activities there must be a compeleted research and investigation.