Lagenidium callinectes INFECTION ON ROTIFERS Brachionus sp.
ABSTRACT: Milkfish, Chanos
chanos and humpback grouper, Cromileptes altivelis hatcheries have developed at
Gondol, Bali since 1995 and until now still rely on rotifers, the main natural
food, supply. Recent problem on mass culture of rotifer, Brachionus sp. is
harvest failure caused by fungus infection. Under light microscope, infected
eggs and bodies of the rotifers was filled with numerous aseptate hyphae. Two
isolates of fungi were isolated from rotifer eggs and carcass on June 21st,
2004 and on June 25th, 2004 obtained from milkfish and humpback grouper
hatcheries at Gondol. Based on its morphological characteristics, the
pathogenic fungus was identified as Lagenidium callinectes which grows
optimally at 25°C and survives in 1.0%, 2.5%, and 5.0% NaCl as well as in 1.0
and 2.5% KCl. Both of the present isolates utilize only 8 out of 26 carbohydrates
and derivatives tested as carbon, nutrition and energy sources. This finding is
the first report on rotifer, Brachionus sp. infected with L. callinectes
causing up to 100% mortality.
KEYWORDS: rotifers, milkfish,
humpback grouper, Lagenidium callinectes
Author: Des Roza and Fris
Johnny
Journal Code: jpperikanangg070007
