Predation potentials of mosquito larvae, Culex pipiens sp., by three kinds of indigenous fish in korea : Aplocheilus latipes (Al), Aphyocypris chinensis (Ac) and Carassius carassius(Cc) were tested in relation to water pollution, in terms of levels of BOD, COD and DO.
The length of survival of the fish was correlated with the pollution grade in general, but Ac showed less resistance than other fish. In BOG 70ppm, Al survived 3 days, Ac 1 day and Cc 4 days. When the BOD density reduced to 40ppm, Al survived 71 days, Ac 11 days and Cc 76 days. In DO 0.3 ppm, AI and Cc survived I day, but Ac were killed within 30 minutes.
In COD, the survival period of each fish was almost similar to BOD conditions above.
Larvivorous activity was prominently greater in Cc than Al and Ac. The number of the ingested larvae per day in BOD 0.5?I.Cppm were :
3 -3.1 per day by Al and Ac, but 195 by Cc. The predation ratios were : Al : Ac : Cc=1.0:1.5: 195 in clean water (BOD 0 ppm), and 1.0 : 0.8 : 91.7 in BOD 4ppm. The fish ate mcsquito larvae as much as commer ? cial bait and the larvivurous potentials were correlated with the size of the fish, in terms of age.
The first instar was more favored by the fish than the pupal stage. In conclusion, Carassius sp. Was the most promising predator among the fish tested under either clean or polluted conditions in laboratory.
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