The Continuous Culture of Rotifer Brachionus plicatilis with Sea water

Abstract

Rotifers are the favourable live food for fish larvae. A steady supply of rotifers is key factor for successful larviculture. The present study aimed to develop a simple zootechnique to reduce labour for high density culture of rotifers. Brachionus plicatilis (inoculation density: 737 ± 80 organisms/ml) were cultured in 100 l plastic, cylindrical tanks using 100% sea water. The water was renewed on every 5 th day of culture without any further exchange of water in between. The culture was continued for 32 days. Rotifers were fed with Chlorella spp. at the rate of 200/ml, twice daily. Total 1059 ± 25 organisms/ml was recorded on day-1 of culture. Significantly (P < 0.05) higher number of rotifers was recorded on day-4 compared to day-1. A 13.12% higher density was recorded on day-8 compared to day-4; the population was reduced 5% on day-12 compared to the previous day. Then the number of rotifer increased gradually. Significantly (P < 0.05) higher number of rotifer (1798 ± 25/ml) was recorded on day-20 compared to the remaining culture period. A gradual decreasing trend was found thereafter. Still the number of organism was more than 1000/ml.