照度对龙虎斑幼鱼行为活动的影响

Effects of Light Intensity on Activities in the Juvenile Hybridized Grouper of Epinephelus fuscoguttatus ♀× E. lanceolatus ♂

龙虎斑幼鱼在运输、转池、过筛等过程中存在应激严重、怕人畏光、食欲低下、抗逆力差、成活率低等问题。以体长5.64±0.16cm、体质量4.99±0.46 g的龙虎斑幼鱼为实验对象,于室内自制循环水养殖系统中研究幼鱼在0、50、100、200、400、800、1 600、3 200 lx等8种照度下的日常行为及摄食状况,实验周期30 d。结果表明：0、50 lx照度组的幼鱼可快速（1 d）适应环境,状态自由,摄食积极;1 600、3 200 lx照度组适应性较差,长时间处于紧张应激状态,于低水层高密度集群;其余各照度组在10 d后达到完全适应状态。摄食水层随着照度的降低而升高,表现出较强的规律性：0 lx〉50 lx〉100 lx〉200 lx〉400 lx〉800 lx〉1 600 lx〉3 200 lx,且15 d前0、50 lx组的摄食水层高于1 600、3 200 lx照度组,差异有统计学意义（P〈0.05）;摄食水平0~800 lx照度组普遍优于1 600、3 200 lx照度组,且10 d前两者差异有统计学意义（P〈0.05）。

The production of juvenile grouper of Epinephelus fuscoguttatus♀ × E. lanceolatus ♂ during the operation of transport, pool transform, screening, etc. were faced some problems of environmental stress, afraid photophobia, poor appetite, body thin, and low survival rate. In order to solve these problems, the appropriate light intensity for juvenile grouper（body length 5.64 ± 0.16 cm,body weight 4.99 ± 0.46 g） were studied. In the experiment the subjects were exposed to eight light intensities（0, 50, 100, 200, 400, 800, 1 600, 3 200 lx） and fed in the self built Recirculating Aquaculture System 30 days in 6 time periods. Daily performance and ingestion status were recorded during the whole feeding period. The results showed that juvenile groupers were quickly adapted to the 0Lx and 50 Lx intensity groups since the first day. Both the 1 600 and 3 200 lx groups perform not very well. They were in the tension stress state and kept high-density closed. The other groups all had adapted to the suitable state after 10 days. The ingestion water level increased with the decrease of illumination, showing a strong regularity： 0 lx〉 50 lx 〉100 lx〉 200 lx〉 400 lx 〉800 lx 〉1 600 lx 〉3 200 lx. The ingestion water level of 0 and 50 lx groups was significantly higher than that of 1 600 lx and 3 200 lx groups during the first 15 days（P〈0.05）, and the ingestion level of the group 0 to 800 lx was significantly higher than that of 1 600 and 3 200 lx groups, with the statistically difference during the first 10 days（P〈0.05）.