after replacing them completely with an
equal volume of fresh sea water Feeding
was done daily to all experimental
and control groups. At the end, the
weight of surviving shrimp larvae (PL-
20) in all the experimental categories
was recorded individually. The survived
PL-20 from all the experimental categories
were separated into two lots of 10
numbers each and transferred to fresh
troughs containing 21 sea water to
assess their resistance to V. harveyi
infection. V. harveyi cell suspension was
introduced into the troughs to get a
concentration of 10'' cells/ml rearing
medium. Larval mortality was noted
daily for upto seven days.