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ID 114117
Title Alternative
A STUDY ON THE SHAPE OF A STRUCTURE FOR MITIGATING THE IMPACT OF LONG-TERM HYPOXIA OCCURRING IN ALL LAYERS ON TRIDENTIGER OBSCURUS
Author
Tanabe, Naoki
Iwami, Kazuki
Hirakawa, Rin
Saito, Minoru
Keywords
Tridentiger obscurus
hypoxia
Amagasaki Canal
shelter
Content Type
Journal Article
Description
底層から表層までの全層にわたって貧酸素化が起こる水環境中で,その貧酸素化の影響を緩和することのできる構造物の形状についての検討を行った.尼崎運河は,慢性的に貧酸素化しており,時には全層で貧酸素化し,年間を通して生存が確認される魚種は底生魚のチチブだけであった.空隙を有する構造物を表層に設置すると,底層のみが貧酸素化するときには,そこを代替の棲み処とし,また全層で貧酸素化したときには水面付近に沈められた板の上に乗り,再曝気されたわずかな酸素を求めて水面に向かって鼻上げ行動をすることがわかった.この時,空隙への選好行動やなわばり行動などのチチブの一般的な行動は認められなかった.以上のことより,貧酸素化する水域では,空隙と定位可能な底面を有する構造物を水面付近に設置するとチチブの避難場として機能することがわかった.
Description Alternative
The shape of a structure capable of mitigating the impact of hypoxia in water environments where hypoxia occurs in all layers from the bottom to the top was studied. The Amagasaki Canal is chronically hypoxic; occasionally all layers are hypoxic. The only fish confirmed to live in this canal throughout the year is the benthonic fish Tridentiger obscurus. This study showed that if a structure with gaps is installed in the surface layer, when only the bottom layer is hypoxic, the fish uses it as a substitute habitat. When all layers are hypoxic, the fish swims above the plate submerged near the water’s surface to obtain aminiscule amount of reaerated oxygen and raise its nose to the surface. Under this condition, Tridentiger obscurus’ preference for and tendency to occupy gaps is absent. The aforementioned observations show that an effective means to mitigate the impact of hypoxia on Tridentiger obscurus is installation of structures with gaps and a bottom surface that the fish can settle on near the water surface.
Journal Title
土木学会論文集B3(海洋開発)
ISSN
21854688
Publisher
土木学会
Volume
75
Issue
2
Start Page
I_1001
End Page
I_1006
Published Date
2019
Rights
© 2019 公益社団法人 土木学会
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
jpn
TextVersion
Publisher
departments
Research Center for Management of Disaster and Environment