Abstract
The effect of high pH (pH 9.25) of rearing water on the prevention of infection of the brine shrimpArtemia salinalarvae with four fungal species of Lagenidiales was examined. The four fungi, all pathogenic to crustaceans, wereHalocrusticida parasiticaisolated from greasyback shrimpMetapenaeus ensis, Haliphthoros sp. andHaliphthoros milfordensisisolated from swimming crabPortunus trituberculatusandLagenidium callinectesisolated from mud crabScylla serrata. Thein vitrogrowth ofHalocrusticida parasitica was reduced at pH 9.25 and no infection was observed in the brine shrimp exposed to zoospores in the sea water at pH 9.25. Thein vitrogrowth ofHaliphthoros sp. andHaliphthoros milfordensiswas reduced at pH 9.25 and infection rates at pH 9.25 were about half of the rate at pH 8. The growth ofL.callinecteswas not arrested at pH 9.25 and the infection rate at pH 9.25 was 100%. These results indicate that the pH adjustment of rearing water to 9.25 can be used to prevent infections withHalocrusticida parasiticaand the two species ofHaliphthorosin swimming crab larvae, but not for the infection withL. callinectes.
