Shrimp culture

Postlarval M. rosenbergii were grown for 28 days in freshwater aquaria
containing nine types of artificial solutions of calcium and magnesium.
Three calcium concentrations (0.05, 0.80, 1.55 mM) were varied against
identical concentrations of magnesium, producing water hardnesses
from 10-310 mg/1 as CaCO3. Shrimp were also grown in well water
whose calcium and magnesium levels matched those of one type of
artificial solution. Other major ions were added to artificial solutions
at concentrations similar to those in well water. Two replications
were run. There was no evidence that survival, final mean weights,
or food conversion ratios were influenced by calcium or magnesium concentrations.
Light intensities ranged from 20-55 ftc; there was a
suggestion that the higher illuminations were more favorable. Shrimp
grown in well water were significantly larger and had significantly
lower food conversion ratios than those grown in the matching artificial
solution. Well water may therefore contain growth-stimulating
substances.

This paper describes a 12-week comparative study of the effects
of aeration vs. non-aeration on growth and survival rates of the freshwater
shrimp, Macrobrachium rosenbergii, reared in outdoor concrete
culture tanks. At four week intervals, the shrimps were counted,
measured and weighed. Shrimps cultivated under aerated conditions
did not grow significantly faster than shrimps cultivated under
non-aerated conditions. Survival rates of shrimps cultivated under
non-aerated conditions were significantly higher than those of shrimps
cultivated under aerated conditions. The physico-chemical parameters
of dissolved oxygen, temperature, pH, turbidity and ammonia concentration
were monitored throughout the experiment. Water hardness was
monitored during the final four weeks only. Water quality was similar
among all tanks, except for pH and dissolved oxygen concentration. From
this study, aeration is not recommended under normal culture conditions
for M. rosenbergii.