THE CONTINUOUS FEEDING OF TURBOT LARVAE, SCOPHTHALMUS-MAXIMUS, AND CONTROL OF THE BACTERIAL ENVIRONMENT OF ROTIFERS

Turbot larvae were fed continuously with rotifers pumped from the culture tanks and rinsed before distribution. This technique improved the growth and survival rates of turbot, in comparison with the results obtained with a single daily distribution of rotifers enriched for 6 h. Special attention was paid to associated bacteria. Most bacteria detected in healthy rotifers and turbot were identified as Vibrio alginolyticus. An opportunistic strain of Aeromonas sp. was observed in large numbers, but only in tanks where the larvae were on the verge of high mortality. A food additive containing live lactic bacteria improved the growth rate of turbot when it was put into the rotifer medium. A similar improvement was observed when the pH of this medium was lowered to 5.26-6, while the temperature was increased from 19 to 26°C. The combination of the bacterial additive and the pH-temperature changes was not efficient and might have led to the proliferation of Aeromonas. © 1990.