• Title/Summary/Keyword: Intermoult period

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Larval Survival Rate and Growth of Pandalus gracilis Using Two Temperature Conditions Reared in the Laboratory (한국산 남방도화새우, Pandalus gracilis유생의 두 온도 구간에서의 생존율과 성장)

  • 최정화;마채우
    • Journal of Aquaculture
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    • v.17 no.1
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    • pp.58-61
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    • 2004
  • Larvae of Pandalus gracilis were reared in the laboratory under controlled conditions (salinity, 32.5∼34.5; photo-periods, 12L: 12D). The experiments were designed to examine effects of temperature (10 and 2$0^{\circ}C$) on larval development, survival, intermolt period and larval growth. The higher survival rate was obtained at 2$0^{\circ}C$ than at 1$0^{\circ}C$ and larvae reached later stages at 2$0^{\circ}C$. Intermolt period increased significantly with increasing of instar number and was longer at 1$0^{\circ}C$ than at 2$0^{\circ}C$.

Toxicity of Copper, Cadmium and Chromium on Survival, Growth and Oxygen Consumption of the Mysid, Neomysis awatschensis (곤쟁이 Neomysis awatschensis와 생존, 성장 및 산소소비에 미치는 구리, 카드뮴, 크롬의 독성)

  • KANG Ju-Chan;KIM Heung-Yun;CHIN Pyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.874-881
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    • 1997
  • In order to estimate toxicity of copper, radmium and chromium on survival, growth and oxygen consumption of the estuarine mysid, Neomysis awatschensis, adult and juvenile, the experiments were conducted by renewal bioassay method at $20{\pm}1^{\circ}C\;and\;20{\pm}1\%_{\circ}$ salinity. The $96hr-LC_{50}$ of the mysid exposed to cadmium, copper and chromium was 20.2, 11.3 and $670.4\;{\mu}g/\ell$ in adut and 3.4, 1.9 and $49.4\;{\mu}g/\ell$ in juvenile, respectively, and were ranked in order of toxicity : copper >cadmium >chromium. Survival rates of the mysid exposed to the sublethal concentrations of heavy metals for 40 days were significantly affected by cadmium $\geq1.0\;{\mu}g/\ell$ and copper $\geq0.6\;{\mu}g/\ell$ concentrations. The growth rate of the mysid exposed to $cadmium\geq2.0\;{\mu}g\ell$ and copper $\geq1.2\;{\mu}g/\ell$ concentrations were significantly reduced than that exposed to normal condition, but there was no affect on intermoult period. Oxygen consumption rate of the mysid exposed to heavy metals was significantly reduced with increasing heavy metals concentrations. The results of the present study led us to conclude that concentrations levels cadmium$\geq1.0\;{\mu}g\ell$ and copper $\geq0.6\;{\mu}g\ell$ of the estuarine could markedly affect the distribution and population of the mysid by reduced survival, growth and oxygen consumption rate.

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