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ID 24659
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title alternative
Effects of low dissolved oxygen and hydrogen sulfide on early developmental stages of blue crab, Portunus trituberculatus in Hiroshima Bay, Japan
creator
Kang, Ju-Chan
Matsuda, Osamu
subject
ガザミ幼生
広島湾
溶存酸素
硫化水素
crab larvae
Hiroshima Bay
hydrogen sulfide
low dissolved oxygen
NDC
Fishing industry. Fisheries
abstract
貧酸素と硫化水素がガザミ幼生に及ぼす影響を実験的に明らかにし、広島湾底層の観測結果から現場海域において海水中の溶存酸素と硫化水素がガザミ幼生に及ぼす複合影響を評価した。ガザミ幼生は48時間の硫化水素の暴露により、ゾエア期では≧5.2μgH2Sℓ-1、メガロパ期では≧9.5μgH2Sℓ-1、稚ガニ期では≧19.7μgH2Sℓ-1で生存率の有意な減少を示した。また、72時間の貧酸素条件によりゾエア期では≦3.4mgO2ℓ-1、メガロパ期では≦2.6mgO2ℓ-1、稚ガニ期では≦1.5mgO2ℓ-1で有意な生存率の減少が認められた。貧酸素と硫化水素の複合的条件下では、ゾエア期には≦3.4mgO2ℓ-1+≧5μgH2Sℓ-1の生存率は≦3.4mgO2ℓ-1の場合よりもさらに低下した。また、メガロパ期には≦3.4mgO2ℓ-1+10.1μgH2Sℓ-1および2.6mgO2ℓ-1+≧5.2μgH2Sℓ-1で、稚ガニ期には2.6mgO2ℓ-1+10.1μgH2S-1で、それぞれ貧酸素単独条件の場合よりも有意な生存率の減少を示した。広島湾奥部と江田内湾内の夏季の底層水中には、飽和度50%の低酸素水塊が認められ、10μgH2Sℓ-1以上の硫化水素濃度が検出された。以上の結果から、広島湾奥部と江田内湾内で、少なくともメガロパ期以前のガザミ幼生は鉛直移動により、底生期の稚ガニでは底生生活により底層水中の貧酸素と硫化水素に暴露されると考えられ、幼生期の自然減少が憂慮される。
abstract
Acute toxicity of hydrogen sulfide to larval stage of blue crab, Portunus trituberculatus was measured using a continous flow system. Survival rates of crab larvae to oxygen deficient water (DO≦3.4 mgℓ-1) and oxygen deficient water (3.4 mgO2ℓ-1 and 2.6 mgO2ℓ-1) with two different levels of hydrogen sulfide (10 μ-gH2Sℓ-1 and 5 μgH2Sℓ-1)were also determined. Survival rate of crab larvae exposed to hydrogen sulfide for 48 hours decreased at H2S≧5.2μgℓ-1, H2S≧9.5μgℓ-1, H2S≧19.7μgℓ-1 levels to zoea, megalopa and crab stage, respectively. Larval survival of zoea, megalopa and crab stage under low oxygen was significantly affected by DO≦3.4 mgℓ-1, DO≦2.6 mgℓ-1, 1.5 mgℓ-1 levels, respectively. The combined effects of low dissolved oxygen and hydrogen sulfide to the blue crab were stronger than each single effect. Namely, survival rate lowered under the combined exposure to≦3.4mgO2ℓ-1+≧5μgH2Sℓ-1, ≦3.4mgO2ℓ-1+10.1μgH2Sℓ-1, ≦2.6mgO2ℓ-1 +10.1μgH2Sℓ-1 levels to zoea, megalopa and crab stage larvae, respectively. The results of the field survey in Hiroshima Bay, Japan revealed that a part of the Bay was hypoxia (<3.2 mgℓ-1) in summer with high levels of hydrogen sulfide (≧10μgH2Sℓ-1)near the bottom. From these results, it could be concluded that the low levels of dissolved oxygen and high hydogen sulfide in the bottom water would affect the natural mortality of crab larvae in Hiroshima Bay.
journal title
Journal of the Faculty of Applied Biological Science, Hiroshima University
volume
Volume 32
issue
Issue 2
start page
61
end page
70
date of issued
1993-12
publisher
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
SelfDOI
language
jpn
nii type
Departmental Bulletin Paper
HU type
Departmental Bulletin Papers
DCMI type
text
format
application/pdf
text version
publisher
department
Graduate School of Biosphere Science
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