Studies On The Artificial Breeding And The Larvae's Anti-Poison Characteristics Of Mytilus Coruscus Gould, 1861

The artificial breeding and the larvae's resistant characteristics to heavy metals and organophosphates of Mytilus coruscus Gould, 1861 from Zhejiang inshore was studied in the paper for the purpose of supplying some useful information on the artificial breeding and scientific sea farming. The results of the experiments are showed as follows:1. Study on the artificial breeding of Mytilus coruscus Gould from the inshores of ZhoushanThis study developed artificial breeding and larval nursery techniques of Mytilus coruscus Gould. The results showed that through intensive culture, the parental mussels can mature enough and produce 8.0×10⁸ ind excellent normal sperm and eggs under artificial conditions. By 36-40 hours, the 6.5×10⁸ ind straight hinges were hatched under temperature 16-18℃, the hatching rate reached 81.3%. After 42 days of intensive nursery, 13633 million mussel larvae settled with average shell length of 0.897-0.970 mm under the temperature 16.8-21℃. Then the mussel larvae were moved into sea area. And two months later, 3794.4 million of mussel seedlings were obtained with average shell length of 12.4±0.2 mm. The survival rate was about 62.0%.2. Acute toxicity of three organophosphorus pesticides to juveniles Mytilus coruscus Gould, 1861Acute toxicity of triazophos, acephate and dichlorvos on Mytilus coruscusjuveniles were studied. The result indicated that the median lethal concentrations (LC₅₀) of triazophos at 24 hours,48 hours,72 hours and 96hours to Mytilus coruscus juveniles were 105.065 mg/L(confidence interval(CI_0.95): [98.487, 111.643]), 103.518 mg/L(CI: [100.496, 106.540]), 102.057 mg/L(CI_0.95: [99.122, 104.992]), 97.150 mg/L(CI: [94.986, 99.314]) , respectively, LC₅₀ of acephate at 24 hours, 48 hours, 72 hours and 96 hours to Mytilus coruscus juveniles were 1537.437 mg/L(CI_0.95: [1461.954, 1612.920]), 1493.609 mg/L(CI_0.95: [1414.051, 1573.167]), 1433.898 mg/L(CI_0.95: [1373.237, 1494.559]), 1357.158 mg/L(CI_0.95: [1307.433, 1406.883]), LC₅₀ of dichlorvos at 24 hours, 48 hours, 72 hours and 96 hours to Mytilus coruscus juveniles are 3.796 mg/L(CI_0.95: [3.504, 4.088]), 3.612 mg/L(CI_0.95: [3.359, 3.865]), 3.347 mg/L (CI_0.95 :[3.164, 3.530]), 3.067 mg/L(CI_0.95: [2.902, 3.232]). The acute toxicity effects of triazophos, acephate, dichlorvos to juveniles of Mytilus coruscus was discussed. The mode of the Mytilus coruscus juveniles' prevention of toxicants in low toxicity groups was to close their shells. But in higher mammalian toxicity groups, they used their feet to move along the wall of container and assemble in the central of the container bottom firstly, and then, closed their shells to evade toxicant. Mytilus coruscus juveniles opened their shells to die if they couldn't close shells. The mode of prevention of toxicants was same with the acute toxicity mode by heavy metals. we also discovered that the safety concentrations (SC) of triazophos, acephate and dichlorvos to Mytilus coruscus juveniles for 96 h were 9.715 mg/L, 135.716 mg/L, 0.307 mg/L. The degree of the toxicity of the three pesticides to Mytilus coruscus juveniles was in the order of dichlorvos > triazophos > acephate. In the study, we considered that dichlorvos to Mytilus coruscus juveniles was moderate toxicity pesticides; dichlorvos and acephate were low moderate toxicity pesticides.3. Acute toxic effects of four heavy metals on juveniles of Mytilus coruscus GouldThe studies on the acute toxicity of Zn²⁺, Cu²⁺, Hg²⁺and Cr⁶⁺ on Mytilus coruscus juveniles were carried out with the water temperature of 27.2±1.0℃. The results showed that the median lethal concentrations (LC₅₀) of Zn²⁺,Cu²⁺,Hg²⁺ and Cr⁶⁺ for 96 h to Mytilus coruscus juveniles was 2.333 mg/L(CI_0.95: [2.069,2.597]), 0.194 mg/L(CI: [0.184, 0.204]), 0.120 mg/L(CI: [0.090, 0.150]) and 14.600 mg/L(CI_0.95: [5.476, 23.724]). The acute toxicity effects of Zn²⁺, Cu²⁺, Hg²⁺and Cr⁶⁺ to Mytilus coruscus juveniles was discussed. The mode of the Mytilus coruscus juveniles' prevention of toxicants in low mammalian toxicity groups was to shut their shells. But in higher mammalian toxicity groups, they used their feet to move along the wall of container and assemble in the central of the container bottom firstly, and then shutted shells to evade toxicant. Mytilus coruscus juveniles opened their shells to die if they couldn't shut shells to prevent toxicants. This mode of prevention of toxicants was similar with Ruditapes philippinarum, Moerella iridescens and Argopecten irradians which belonged to Lamellibranchia. To higher mammalian toxicity groups, Mytilus coruscus juveniles' prevention of toxicants mode distinguished from the other bivalve species at the incipient stage of the experiment. We discovered that the safety concentrations(SC) of Zn²⁺, Cu²⁺, Hg²⁺and Cr⁶⁺ to Mytilus coruscus juveniles for 96 h were 0.233 mg/L, 0.019 mg/L, 0.012 mg/L and 1.460 mg/L. The order of the toxicity of these heavy metals was Hg²⁺>Cu²⁺>Zn²⁺>Cr⁶⁺ in turn . In the study, we considered that Cu²⁺, Hg²⁺ to Mytilus coruscus juveniles were very toxic heavy metals, Zn²⁺ was moderate toxicity heavy metals, Cr⁶⁺ was low moderate toxicity heavy metals.