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Studies on cryptocaryoniasis in marine fish: effect of temperature and salinity on the reproductive cycle of Cryptocaryon irritans Brown, 1951 |
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| Authors: | P J CHEUNG R F NIGRELLI G D RUGGIERI |
| Institution: | Osborn Laboratories of Marine Sciences, New York Aquarium, New York, USA |
| Abstract: | Abstract. Trophonts of Cryptocaryon irritans Brown from infected three-spot damselfish, Dascyllus trimaculatus Ruppell, were kept at temperatures ranging from 7 to 37°C to observe encystment and development of the tomites. At 30, 25 and 20°C, the percentage of trophonts that had encysted in 16 h were 70, 77 and 64% respectively; at 37°C, 44% encysted and at 7°C only 10% had encysted. The optimum temperature for excystment was 30°C; 50% excysted in 5 days and 100% in 7 days. At 25°C, 60% of the tomites started to excyst on the eighth day, and 70% on the ninth day. At 20°C, 10% started to excyst on the ninth day, reaching 40% on the tenth day. No excystment occurred at 37 and 7°C. Newly encysted tomonts were placed in various dilutions of sea water (31 % |
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