عنوان مقاله [English]
With regard to the importance of recovery time in rearing ponds of live food for fish following a chemical treatment/ this study was carried out to investigate the effects of different concentrations of Trichlorophen (Diptrex, 97% animal) on the control of mortality time (LT50) and determination of LC50 within 24h in 10-day grown Apus (Triops cancriformis) as an unwanted species in ponds. In doing so, Trichlorophen were obtained in different concentrations of 1, 0,75, 0,5, 0,4, 0,3, ٠٫٢ and ٠٫١ppm and their efficacies on the start time of mortality and time to LC٥٠ were studied in Apus. Results indicated that Apus were killed significantly (P<٠٫٠٥) more rapidly in ١ and ٠٫٧٥ppm than other treatments. Also, the least time until LC٥٠ was observed in ١ppm (P<٠٫٠٥). In this study, ٥٠٪ of mortality was obtained in ٠٫١ and ٠٫٢ppm within ٢٦ and ٢٢٫٥h, respectively. Conclusively, ٠٫١ppm was considered to be used as LC٥٠ for Apus species in order to achieve the average rate of mortality (٥٠٪) with the lowest expenditure in the use of this chemicals and particularly rapidly recovery time in treated ponds.