EFECTO DE LA SALINIDAD SOBRE EL CRECIMIENTO POBLACIONAL Y EL RENDIMIENTO DEL ROTIFERO BRACHIONUS PLICATILIS (CEPA CIENAGA GRANDE DE SANTA MARTA)

Abstract

The effect of salinity on the population growth and yield of a strain of Brachionus plicatilis (O.F. Muller, 1786) was determined by two laboratory experiments. The .rotifer B. plicatilis was isolated from the plankton of the Cienaga Grande de Santa Marta, Colombia, and cultivated in laboratory under different salinity conditions. The local microalgae Chlorelia sp., also isolated in laboratory, was used as food for the rotifers. Salinity values ranged from 3 to 24 o/oo in the first experiment and 30 to 45 o/oo in the second. It was found that these rotifers grow and exhibit a' high adaptive capability when cultured at salinities ranging from 16 to 40o/oo. The rotifer curves of population growth were negative at salinities under 16 o/oo. At salinities of 30, 36, and 40 o/oo the maximum densities were similar in the ninth day. Although maximum densities were somewhat lower at 45 o/oo salinity, no significant statistical differences were found. Maximum values of density (d), yield (y), instantaneous growth rate (k) and doubling time (td) corresponded to a salinity of 36o/oo.