光照强度对缢蛏稚贝生长的影响

为考察缢蛏育苗过程中光强的控制幅度, 研究了不同光照强度对缢蛏稚贝生长的影响. 试验分别选择1mm和5mm不同附着基厚度和4组不同光照强度试验, 时间为10d, 平均光强分别为A: (12244±5290)lx、B: (3792±2105)lx、C: (380±145)lx、D: (14±11)lx(光暗比12h:12h). 当附着基厚度为1mm时, 初始大小(0.26±0.02)mm缢蛏稚贝在A、B、C、D组的生长大小和成活率分别为(1.17±0.11)mm和(72.2±3.9)%、(1.25±0.12)mm和(84.6±4.1)%、(1.55±0.13)mm和(89.7± 4.5)%, (1.32±0.11)mm和(82.1±3.6)%. C组缢蛏稚贝生长大小和成活率都最大, 各组差异显著. 当附着基厚度为5mm时, 缢蛏稚贝在A、B、C、D组的生长大小和成活率分别为(1.48±0.12)mm和(86.3±3.7)%、(1.52±0.13)mm和(89.6±3.9)%、(1.62±0.14)mm和(88.4±4.0)%, (1.41±0.11)mm和(84.3±3.9)%. C组缢蛏稚贝生长大小和成活率都最大, 但是各组没有显著差异. 当实验对象换成较大(1.45±0.16)mm缢蛏稚贝, 光照强度对于薄附着基内稚贝的生长的影响更为明显. 结果表明: 光照强度对缢蛏稚贝生长有明显影响, 稚贝生长过程中最适的光照强度为(380±145)lx, 高于或低于此光照范围, 稚贝的生长率都会受到不同程度的抑制; 适当增加附着基厚度有利于高光强下大规格稚贝的发育生长.

Effects of Light Intensity on Growth of Juvenile Sinonovacula constricta (Lamarck, 1818)

In order to explore the optimal light intensity for the breeding process of Sinonovacula constricta (Lamarck, 1818), the effect of light intensity on the growth of juvenile S. constricta (Lamarck, 1818) is studied. Two substratum thicknesses (1 and 5 mm) and four light intensity gradients including (12244±5290)lx, (3792±2105)lx, (380±145)lx, and (14±11)lx (12h light: 12h dark) are set up in a 10-day experiment. When substratum thickness of 1 mm is applied, the body length and survival rate of S. constricta juveniles (initial body length (0.26±0.02) mm from A, B, C and D groups are (1.17±0.11)nm, (1.25±0.12)nm, (1.55±0.13)nm and (1.32±0.11)nm, and (72.2±3.9)%, (84.6±4.1)%, (89.7±4.5)% and (82.1±3.6)%, respectively. The body length and survival rate of razor clam in Group C are found to be the largest with a significant difference compared with those in other groups. When the substratum thickness of 5 mm is applied, the body length and survival rate of S. constricta juveniles from A, B, C and D groups are (1.48±0.12)nm, (1.52±0.13)nm, (1.62±0.14)nm and (1.41±0.11)nm, and (86.3±3.7)%, (89.6±3.9)%, (88.4±4.0)%, and (84.3±3.9)%, respectively. The body length and survival rate of Razor clam in Group C show no significant difference. When the sample shellfish are changed to larger size of razor clam (initial length (1.45±0.1)nm), the more obvious effect of light intensity on the growth is observed in substratum thickness of 1 mm than 5 mm. These results indicate that light intensity impose a significant impact on the growth of juvenile S. constricta (Lamarck, 1818), and the optimal light intensity for the growth of juveniles is found to be (380±145)lx. In addition, increased thickness of substratum may result in the beneficial growth and development of the large-size juveniles under the condition with high light intensity.