Combined Effects of Hypoxia and Hydrogen Sulfide on Early Developmental Stages of White Shrimp Metapenaeus monoceros

ヨシエビの初期発達段階に及ぼす貧酸素と硫化水素の複合的影響

Kang Ju-Chan

Matsuda Osamu

生物生産学研究

Journal of the Faculty of Applied Biological Science, Hiroshima University

貧酸素と硫化水素が単独あるいは複合的にヨシエビの初期発達段階に及ぼす影響を実験的に明らかにした。ヨシエビのゾエア期,ミシス期,稚エビ期幼生に対する硫化水素の48hr-LC50は、それぞれ8.7, 11.4, 18・5μgSℓ-1であった。貧酸素条件下でヨシエビの幼生の生存率は、ゾエア期ではDO濃度3.4mgℓ-1以下、ミシス期と稚エビ期ではDO濃度1.5mgℓ-1で有意に減少した。貧酸素と硫化水紫の複合的な条件下でヨシエビ幼生の生存率は、ゾエア期とミシス期ではDO濃度3.4mgℓ-1以下と硫化水素濃度10μgSℓ-1、稚エビ期ではDO濃度2.5mgℓ-1以下と硫化水素濃度10μgSℓ-1で貧酸素単独条件下よりも有意な減少を示した。以上の結果を瀬戸内海の夏季の底層水中の溶存酸素と硫化水素濃度に適用してみると、そこに生息するヨシエビ幼生の資源は海域によって大きな悪影響を受けるものと考えられる。

Acute toxicity of hydrogen sulfide to larval stages of white shrimp Metapenaeus monoceros was measured by using the continuous flow through system. Survival rates of white shrimp larvae exposed to hypoxia (≦3.4mgO2ℓ-1) and hypoxia (2.5, 3.4 mgO2ℓ-1) with two different levels of hydrogen sulfide (5, 10 μgSℓ-1) were also determined. The 48hr-LC50 values of hydrogen sulfide were 8.7, 11.4 and 18.5 μpgSℓ-1 for zoea, mysis and juvenile, respectively. Survival rates of zoea, mysis and juvenile exposed to hypoxia were significantly affected by ≦3.4 mgO2ℓ-1, ≦1.5 mgO2ℓ-1 and ≦1.5 mgO2ℓ-1, respectively. Combined effects of hypoxia and hydrogen sulfide were stronger than each single effect. Namely, survival rate was reduced under the combined exposure to ≦3.4 mgO2ℓ-1+10 μgSℓ-1, ≦3.4 mgO2ℓ-1+10 μgSℓ-1 and ≦2.5 mgO2ℓ-1+10 μgSℓ-1 levels to zoea, mysis and juvenile, respectively. From these results, it could be concluded that combined effects of the hypoxia and hydrogen sulfide reported in the coastal region of the Seto Inland Sea, Japan in summer stratification would have affected the larval population of white shrimp in the area.

developmental stage

hydrogen sulfide

hypoxia

toxicity

white shrimp

毒性

発達段階

貧酸素

ヨシエビ

硫化水素

Fishing industry. Fisheries [ 660 ]

eng

広島大学生物生産学部

農林水産研究情報センター

[ISSN] 1341-691X

[NCID] AN10409040