不同养殖密度对紫贻贝和披针形蜈蚣藻生态混养的影响

通过混养生态系统模拟试验研究了紫贻贝(Grateloupia lanceolata)和披针形蜈蚣藻(Mytilus edulis)不同养殖密度组合下的生态混养状况。选取壳长(45.14±3.85)mm的紫贻贝和长度(62.48±7.38)mm的披针形蜈蚣藻,采用5种湿重配比进行混养实验,分别为G1(1∶0)、G2(1∶0.25)、G3(1∶0.5)、G4(1∶1)和G5(1∶2)。每种组合中紫贻贝密度均为0.63 ind·L~(-1),而披针形蜈蚣藻密度分别为0 g·L~(-1)、1.25 g·L~(-1)、2.5 g·L~(-1)、5 g·L~(-1)、10 g·L~(-1)。36 d后,G3组中紫贻贝特定生长率为(0.21±0.03)%·d-1,极显著高于其它混养组(0.11±0.028)~(0.21±0.03)%·d-1,P0.01],而单养组的紫贻贝特定生长率仅为(0.063±0.022)%·d-1;G3组中披针形蜈蚣藻特定生长率为(0.96±0.20)%·d-1,极显著高于其它混养组(0.62±0.16)~(0.96±0.20)%·d-1,P0.01]。G3组生态系统对营养盐(NO_3~--N、NO_2~--N、NH_4~+-N、PO3-4-P)的去除率分别达到(91.38±1.40)%、(96.79±1.97)%、(98.38±2.06)%、(96.86±3.16)%,显著高于G2组(P0.05),而与G4和G5组没有显著性差异(P0.05)。本研究结果表明,当紫贻贝与披针形蜈蚣藻湿重比为1∶0.5时,可以取得较好的生态效应。

Effects of different culture densities on the ecological polyculture of Mytilus edulis and Grateloupia lanceolata

Grateloupia lanceolata is a kind of seaweed which widely grows in the waters of Gouqi Island.It can be used for eating and algin extraction, so with high economic and medicinal values, which makes it have the exploitment and utilization prospects.Mytilus edulis is one of the most important marine shellfishes in China whose cultivation mainly concentrates around the Shengsi Island of Zhoushan City in Zhejiang Province and the scale is expanding year by year.However, due to the continuous expansion of cultivation area and the increasing cultivation density, in recent years, the eutrophication of the mariculture area has been serious, leading the red tide breaking out frequently.This paper studied on the polyculture of Mytilus edulis and Grateloupia lanceolata in order to improve the environment of the regional aquaculture area.Polyculture systems of Mytilus edulis and Grateloupia lanceolata were set as 5 treatment groups and the polyculture of the Mytilus edulis with the Grateloupia lanceolata densities were G1 (1 ∶ 0), G2 (1∶0.25), G3 (1∶0.5), G4 (1∶1) and G5 (1∶2).The Mytilus edulis was bred at the density of 0.63 ind·L-1 in each group, while the Grateloupia lanceolata were cultivated at different densities of 0 g·L-1, 1.25 g·L-1, 2.5 g·L-1, 5 g·L-1 and 10 g·L-1.After 36 d, the specific growth rate of Mytilus edulis in G3 was 0.21 ± 0.03 %·d-1, significantly higher than those in the other polyculture groups (0.11 ± 0.028-0.21 ± 0.03 %·d-1, P<0.01), and the specific growth rate of Mytilus edulis monoculture was only 0.063 ± 0.022 %·d-1 (P<0.01).The specific growth rate of Grateloupia lanceolata in G3 group was 0.96 ± 0.20 %·d-1, which was significantly higher than those of the other polyculture groups (0.62 ± 0.16-0.96 ± 0.20 %·d-1, P<0.01).The removal rates of nutrients (NO-3-N, NO-2-N, NH+4-N, PO3-4-P) in G3 were 91.38 ± 1.40 %, 96.79 ±1.97 %, 98.38 ± 2.06 % and 96.86 ± 3.16 % respectively, which were significantly higher than G2 (P<0.05) , but had no significant difference between G4 and G5 (P>0.05).In conclusion, the polyculture of Mytilus edulis with Grateloupia lanceolata can exert reasonable ecological effects when the density ratio is 1∶0.5.