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- Araki Akira
Araki Akira
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Journal of National Fisheries University Volume 72 Issue 1
pp. 1 - 9
published_at 2023-12
We investigated the hemolymph oxygen and acid–base status of Akoya pearl oysters, Pinctada fucata martensii, exposed to hypoxic seawater to elucidate the acid–base balance. Akoya pearl oysters cannulated to the anterior aorta for hemolymph collection from the submerged animals showed oxygen and acid–base disturbance of the hemolymph during environmental hypoxia for 24 h (O_2 partial pressure in seawater, Pwo_2 8 torr). The hemolymph O_2 partial pressure (Po_2) decreased from 72.2 torr to 13.6 torr, pH decreased from 7.581 to 7.129, and CO_2 partial pressure (Pco_2) increased from 0.86 torr to 3.31 torr during hypoxia. The hemolymph total CO_2 concentration (Tco_2) and bicarbonate ion concentration ([HCO_3^–]) were 1.93–1.95 mM/L and 1.80–1.91 mM/L, respectively, and there was no statistically significant change between pre-hypoxia and hypoxia for 24 h. When normoxic seawater was resumed after the hypoxia, the hemolymph Po_2, pH, and Pco_2 returned to their initial levels for about 3 h, and hemolymph Tco_2 and [HCO_3^–] gradually increased. These results showed that Akoya pearl oysters undergo hypoxemia and respiratory acidosis in the hypoxic environments for 24 h (Pwo_2 8 torr). In post-hypoxia, most of the disturbances disappeared within 3–24 h, and the increase in hemolymph [HCO_3^–] which was a secondary change compensated for respiratory disturbance.
Journal of National Fisheries University Volume 71 Issue 2
pp. 43 - 55
published_at 2023-01
We aimed to clarify the microhabitat preferences of Atyidae shrimps in the middle to upper reaches of the Hiwasa R. , Kitagawatidani R. , and Mugi R. , Tokushima Prefecture, southern central Japan. Relationships between the shrimp abundance and physical environmental variables were surveyed at six sites in 2011 fall and 2012 spring by setting 5-m line transects delineated with ten consecutive 50-cm quadrats along the riverbank. The dominant shrimp species collected from the riverbanks were Caridina multidentata, Paratya compressa and Neocaridina denticulata. C. multidentata was shown to prefer loose boulder or cobble beds with interstices. When interstices were scarce, the shrimps were found inhabiting among the vegetation. P. compressa was shown to prefer vegetation and boulder or cobble bed in pools. N. denticulata tended to prefer vegetation in darker, gently-flowing areas. Our results insist that the three shrimp species segregate microhabitat under base-flow conditions, but flow reduction may cause microhabitat overlap between C. multidentata and P, compressa.
Creators :
Yonezawa Takayasu
Saito Minoru
Hatama Toshihiro
Araki Akira
Oka Naohiro
Hamano Tatsuo
Publishers : National Fisheries University
Journal of National Fisheries University Volume 71 Issue 2
pp. 35 - 42
published_at 2023-01
We investigated the hemolymph oxygen and acid–base status of akoya pearl oysters, Pinctada fucata martensii, exposed to air for a short time (4 h) to elucidate the acid–base balance and CO_2 dynamics. The hemolymph O_2 partial pressure (Po_2) in air-exposed akoya pearl oysters decreased from 88.7 torr (mean value) to 29.4 torr at 1 h, and the low Po_2 continued for the next 3 h during air exposure. The hemolymph pH decreased from 7.586 to 7.082 during air exposure for 1 h and reached 6.851 at 4 h. The hemolymph CO_2 partial pressure increased from 0.9 torr to 4.4 torr at 1 h and reached 7.3 torr after 4 h of air exposure. The hemolymph bicarbonate concentration and calcium ion concentration at 0 h (control) were 1.9 mM/L and 9.0 mM/L, respectively, and these properties did not significantly change during air exposure. From these results, it was determined that the akoya pearl oysters had hypoxemia caused by hypoventilation at an early phase of the short-term air exposure. The akoya pearl oysters inhibited the discharge of CO_2 by hypoventilation, and respiratory acidosis was caused due to the excessive accumulation of CO_2. Bicarbonate was not mobilized from the shell valve into the hemolymph during the short-term air exposure.
Journal of National Fisheries University Volume 71 Issue 1
pp. 1 - 9
published_at 2022-12
We investigated the oxygen and acid–base status of the densely lamellated oyster, Ostrea denselamellosa, during air exposure for 24 h. The hemolymph O_2 partial pressure decreased from 68.0 torr (mean value) to 52.1 torr during air exposure for 18 h, and reached 42.1 torr after 24 h. The hemolymph pH decreased from 7.579 to 6.798 at 18 h and to 6.361 at 24 h. The hemolymph CO_2 partial pressure increased from 1.30 torr to 40.9 torr at 24 h during air exposure. The hemolymph bicarbonate concentration increased from 1.36 mM/L to 2.81 mM/L at 24 h. The hemolymph calcium ion concentration increased from 8.2 mM/L to 10.9 mM/L at 24 h. From these results, it was revealed that the densely lamellated oysters caused a progressive hypoxemia by hypoventilation of the gill during air exposure. The densely lamellated oysters were inhibited from releasing CO_2 from the gill by hypoventilation, and respiratory acidosis was caused due to the accumulated CO_2. The densely lamellated oysters exposed to air for a long time developed metabolic acidosis due to anaerobic metabolism partially compensated with mobilized [HCO_3^–] from the shell valve.
Journal of National Fisheries University Volume 70 Issue 3
pp. 69 - 77
published_at 2022-01
We investigated the oxygen and acid–base status of the noble scallop Mimachlamys nobilis during air exposure for 24 h. The hemolymph of noble scallop was collected from the adductor muscle, and O_2 partial pressure (Po_2), pH, CO_2 partial pressure (Pco_2), and bicarbonate ion concentration ([HCO_3^–]) were examined during air exposure. Hemolymph Po_2 decreased from 69.5 torr (mean value) to 46.3 torr during air exposure for 6 h, and reached to 19.0 torr after 24 h. The hemolymph Po_2 of air-exposed noble scallops decreased gradually and caused progressive hypoxemia by hypoventilation of the ctenidium. Air-exposed noble scallops showed a reduction in pH and elevation of Pco_2 and [HCO_3^–] of the hemolymph. In air-exposed noble scallops, the hemolymph pH decreased from 7.460 to 7.045 at 6 h and to 6.348 at 24 h. The hemolymph Pco_2 increased from 1.30 torr to 5.05 torr at 6 h and to 56.6 torr at 24 h during air exposure. The [HCO_3^–] increased from 1.26 mM/L to 1.88 mM/L at 6 h and to 4.19 mM/L at 24 h. N32From these results, in the first 6 h of air exposure, noble scallops mainly underwent respiratory acidosis by excess accumulation of CO_2 due to hypoventilation. Meanwhile, after 24 h of air exposure, noble scallops showed mainly metabolic acidosis partially compensated by mobilized [HCO_3^–] from the shell.
Journal of National Fisheries University Volume 70 Issue 1
pp. 11 - 25
published_at 2021-10
The vertical migration of the first stage of five diadromous atyids (Caridina multidentata, C. typus, C. leucosticta, C. serratirostris, Paratya compressa) and two diadromous palaemonids (Macrobrachium japonicum, M. formosense) and a non-diadromous palaemonid shrimp (M. nipponense) and second zoeae of C. multidentata and M. formosense were observed under different light and salinity conditions. The first and second zoeae spread over the whole of the water column during darkness, and sank to the bottom under the light independent of the various salinity and light conditions, though there were slight differences among species. The swimming ability of the zoea is limited, thus this vertical migration is considered to be not useful for homing migration. This vertical migration at night is considered to be useful in order to feed on organic material and avoiding predators on the bottom.
Journal of National Fisheries University Volume 69 Issue 1
pp. 9 - 15
published_at 2020-11
Journal of National Fisheries University Volume 69 Issue 1
pp. 1 - 8
published_at 2020-11
Journal of National Fisheries University Volume 62 Issue 1
pp. 9 - 12
published_at 2013-09
Journal of National Fisheries University Volume 68 Issue 2
pp. 65 - 70
published_at 2020-01
Journal of National Fisheries University Volume 67 Issue 3
pp. 133 - 139
published_at 2019-03
Journal of National Fisheries University Volume 66 Issue 4
pp. 203 - 208
published_at 2018-03
Journal of National Fisheries University Volume 66 Issue 3
pp. 141 - 172
published_at 2018-03
Journal of National Fisheries University Volume 66 Issue 3
pp. 103 - 110
published_at 2018-03
Creators :
Handa Takeshi
Araki Akira
Kawana Koji
Yamamoto Ken-ichi
Publishers : National Fisheries University
Journal of National Fisheries University Volume 66 Issue 1
pp. 35 - 40
published_at 2017-11
Journal of National Fisheries University Volume 66 Issue 1
pp. 13 - 34
published_at 2018-11
Journal of National Fisheries University Volume 65 Issue 3
pp. 167 - 184
published_at 2017-03
Journal of National Fisheries University Volume 65 Issue 3
pp. 147 - 165
published_at 2017-03
Journal of National Fisheries University Volume 65 Issue 2
pp. 69 - 111
published_at 2017-01
Journal of National Fisheries University Volume 65 Issue 2
pp. 47 - 67
published_at 2017-01
Journal of National Fisheries University Volume 65 Issue 2
pp. 39 - 46
published_at 2017-01
Journal of National Fisheries University Volume 46 Issue 1
pp. 27 - 31
published_at 1997-10
Journal of National Fisheries University Volume 46 Issue 1
pp. 21 - 26
published_at 1997-10
水産大学校研究報告 Volume 50 Issue 2
pp. 75 - 81
published_at 2002-02
水産大学校研究報告 Volume 51 Issue 3
pp. 87 - 94
published_at 2003-03
Creators :
Ooishi Shunsuke
Hamano Tatsuo
Araki Akira
Hayashi Ken-ichi
Watanabe Toshiaki
Yokota Motohiro
Publishers : 水産大学校
水産大学校研究報告 Volume 52 Issue 3
pp. 113 - 112
published_at 2004-03
Creators :
Hamano Tatsuo
Fukuizumi Hiromu
Araki Akira
Takeshita Naohiko
Watanabe Toshiaki
Yokota Motohiro
Publishers : 水産大学校
水産大学校研究報告 Volume 52 Issue 3
pp. 93 - 112
published_at 2004-03
Creators :
Hamano Tatsuo
Karimata Hirofumi
Matsukura Kazuki
Araki Akira
Nagamatsu Kimiaki
Hamaguchi Masato
Aoki Kunimasa
Publishers : 水産大学校
Journal of National Fisheries University Volume 64 Issue 3
pp. 204 - 220
published_at 2016-03
Journal of National Fisheries University Volume 64 Issue 2
pp. 144 - 171
published_at 2016-02
Journal of National Fisheries University Volume 64 Issue 2
pp. 120 - 142
published_at 2016-02
Journal of National Fisheries University Volume 64 Issue 2
pp. 104 - 119
published_at 2016-02
Journal of National Fisheries University Volume 60 Issue 1
pp. 37 - 42
published_at 2011-10
Journal of National Fisheries University Volume 61 Issue 1
pp. 11 - 14
published_at 2012-09
Creators :
Yamamoto Ken-ichi
Handa Takeshi
Araki Akira
Minato Yoshiyuki
Odawara Kazusi
Sone Ken-ichi
Publishers : National Fisheries University
Journal of National Fisheries University Volume 62 Issue 1
pp. 39 - 45
published_at 2013-09
Journal of National Fisheries University Volume 62 Issue 1
pp. 5 - 8
published_at 2013-09
Journal of National Fisheries University Volume 62 Issue 1
pp. 1 - 4
published_at 2013-09