海带育苗水系微生物的监测与控制

BACTERIAL ABUNDANCE MONITER AND CONTROL IN THE SEAWATER SYSTEM OF LAMINARIA SUMMER SPORELING CULTURE STATIONS

现场及实验室试验表明,近岸水中细菌丰度因时因地有较大差别,近岸水在潮周期中以高潮前后细菌量较低;海水在沉淀贮存过程中细菌丰度有明显变化,且与海水中营养物含量、贮存温度等有关;海水经沙滤后能减少细菌90％左右;回水中脱落苗进入贮水池,是贮水池中细菌数量增长10余倍的主要原因。

The bacteria that may induce disease of Laminaria summer sporeling at culture stations-can be commonly found in' coastal seawater. In order to prevent these sporelings from disease it is necessary to monitor and control the bacterial abundance in cultivation seawater system.The availability of nutrient in coastal area is the main factor which influences the bacterial abundance in seawater. pumping site should be carefully selected in order to get better quality seawater with low nutrient.In coastal area bacterial abundance varies with the tidal cycle, minimum abundance usually occurs at high tide.Heterotrophic bacterial population increase apparently once the seawater is stored in large tanks, and is greatly influenced by the available nutrient level of the seawater.Sand filteration is an effective way in reducing bacterial abundance in seawater system at Laminaria sporeling culture station. These sand should always be washed to keep effectiveness of its filteration.Many drafting juvenile Laminaria in culture tanks will accelarate bacteria multiplication in seawater promptly. Those debris should be removed before reusing these seawater.