Assessing chemical compounds
for controlling predator ciliates in outdoor mass cultures of the green
algae Dunaliella salina
I. Moreno-Garrido, J.P. Cañavate-2001
Aquacultural Engineering, 24(2): 107-114
Abstract:
Effects of different chemical compounds on ciliates
grazing outdoor mass cultures of Dunaliella salina were studied.
These taxonomically undetermined ciliates were capable of clarifying dense
algal cultures within 2 days and tolerated a wide salinity range (up to 215
ppt). Treatments of micro-algal cultures with either formaldehyde, ammonia,
hydrogen peroxide or metronidazole were inappropriate since lethal doses for
the ciliate also eliminated algal cells. However, the use of quinine
sulphate rapidly destroyed ciliates while keeping algal cells alive. A 24-h
LC100 at 12-14 mg/l quinine sulphate was found for the ciliate, whereas a
72-h EC50% at 14.5±0.6 mg/l was found for Dunaliella. The
application of a dose of 10 mg/l quinine to contaminated outdoor algal mass
cultures completely eliminated ciliates within a short time, and allowed the
algal population to start recovering.
(Centro de Investigación
y Cultivo de Especies Marinas « El Toruño » Apartado 16, 11500,
El Puerto de Santa María, Cádiz, Spain, E-mail : ignacio.moreno@icman.csic.es)