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1.
ABSTRACT: The migratory history of anadromous white-spotted charr Salvelinus leucomaenis collected from Japanese coastal waters, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith, by means of wavelength dispersive X-ray spectrometry using an electron microprobe. Otolith Sr concentration or Sr : Ca ratios of anadromous S. leucomaenis , fluctuated strongly along the life history transect in accordance with the migration (habitat) pattern from sea to fresh water. The anadrmous S. leucomaenis showed phase L (low Sr : Ca ratio) from the core to the point 1000–2500 µm distant, averaging 1.3 × 10−3 to 2.7 × 10−3 and thereafter, the ratios increased sharply, being higher than 5.0 × 10−3 to 10.0 × 10−3 . These findings indicated that otolith Sr : Ca ratios reflected individual life histories, enabling a sea habitat to be identified from a freshwater habitat in this species. 相似文献
2.
Takaomi Arai 《Fisheries Science》2010,76(3):451-455
In order to determine the salinity effect on otolith strontium (Sr):calcium (Ca) ratios, the Sr and Ca contents of otoliths
of Sakhalin taimen, Hucho perryi, reared for 60 days in four salinities (freshwater, one-third seawater, two-thirds seawater, and full seawater) were examined.
The Ca and Sr contents and the resultant Sr:Ca ratios in the rearing water increased linearly with salinity. Otolith Sr:Ca
ratios were also found to be positively correlated with salinity. However, the Sr:Ca did not correspond to temperature fluctuations
during the experiment. These results indicate that Sr:Ca ratios in otoliths can be used to reconstruct the migratory history
of the fish by differentiating when the fish migrated between freshwater and seawater. 相似文献
3.
Determination of trace elements in otoliths of chum salmon Oncorhynchus keta by laser ablation-ICP-mass spectrometry 总被引:1,自引:0,他引:1
Trace element levels in the otoliths of chum salmon Oncorhynchus keta were examined by means of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). A close linear relationship
in the Sr/Ca ratios between X-ray analysis with an electron microprobe (EPMA) and LA-ICPMS analysis was found, suggesting
that the latter technique could be used to distinguish the marine and freshwater life phases. Mg, Zn, Ba and Sr concentrations
of the otoliths differed between the freshwater and seawater growth zones. Mg and Zn concentrations in the freshwater growth
zone were significantly higher than those in the seawater growth zone, while Sr and Ba concentration s in the former were
significantly lower than in the latter. The relationship between Sr concentration and Mg, Zn, and Ba concentrations at each
ablation showed significant correlations. These results suggest that trace element compositions may reflect differences between
freshwater and seawater environmental conditions. 相似文献
4.
Quang Dung Le Kotaro Shirai Duc Cu Nguyen Nobuyuki Miyazaki Takaomi Arai 《Water, air, and soil pollution》2009,204(1-4):69-78
In order to understand the present status of heavy metal contamination and the risk associated with human consumption, commercial freshwater eels in Vietnam were examined. The concentration of eight elements (Cr, Mn, Co, Cu, Zn, Sr, Cd, and Pb) was determined in muscle tissue of tropical eel Anguilla marmorata collected in four provinces, Quang Tri, Quang Ngai, Binh Dinh, and Phu Yen, from the central part of Vietnam. Concentrations of Cu, Zn, Cd, and Sr were found to be highest, whereas Co concentration showed the lowest at Quang Tri. Cr was recorded to be lowest in Quang Ngai, while the amounts of Mn and Pb did not vary among locations. Although the metal concentrations in the muscle of A. marmorata did not represent a risk for human consumption, elevated Cd concentrations in Quang Tri related to agriculture activities suggest that further investigations should be undertaken to clarify the potential risk to the eel population. 相似文献
5.
Kenji Tanaka Yoshitaka Funakoshi Takaomi Hokamura Fumihiko Yamada 《Paddy and Water Environment》2010,8(3):217-226
Agricultural fields in the middle Shira River basin play an important role as a source of groundwater recharge; however, the
water balance between the agricultural water and river water is unclear. This study was conducted to investigate the water
balance in the fields by measuring the stream flow of agricultural water channels, which draw water from the Shira River.
The flow rate of water channels was found to increase in the beginning of May, which corresponded to the cultivation of paddy
rice fields. During summer, the total agricultural intake was comparable to the river flow observed in the middle Shira River
Basin. Determination of the water budget for the targeted area revealed that most of the recharged water was dependent on
agricultural irrigation from the river. The annual recharge of the overall target area was estimated to be as high as 15,300 mm.
In addition, the infiltration rate was as high as 170 mm/day in the paddy fields during summer, and as high as 30 mm/day in
the upland fields during winter. In order to recover the groundwater recharge in this region, it is necessary to extend the
submerged period to include periods in which the stream water in the Shira River is not subject to heavy rainfall as well. 相似文献
6.
Masu salmon Oncorhynchus masou masou divides into two life histories after a year of life in the river, the sea-run form and the fluvial form. Since salmons are anadromous, the sea-run form salmons are known to pollute the river sediments during spawning migration. In this study, we have studied the accumulation of organochlorines in the fluvial form as well as the sea-run form, and discussed their differences. In order to elucidate the accumulation patterns of organochlorines in both the fluvial and sea-run form masu salmons, the concentrations of organochlorines were determined in the muscle of both life histories. The organochlorines in the sea-run form were 7 to 21 times higher than those of fluvial form. Since salmons are semelparous, the carcasses of polluted sea-run form pollute the river sediments. The trans-nonachlor/trans-chlordane (N/C) ratio in the fluvial form (1.93) was significantly lower than that of sea-run form (23.8). This indicates that the fluvial form is polluted by comparatively newly input chemicals. These results suggest that sea-run form masu salmons have the potential to pollute the river sediments secondarily as vectors, but from the difference in N/C ratio between the two forms, the fluvial fish does not seem to be polluted by those organochlorine compounds of sea-run fish origin yet. 相似文献
7.
Takaomi Arai 《Fisheries Science》2006,72(2):382-387
ABSTRACT: The habitat use and migration of ayu Plecoglossus altivelis was compared to that of ice goby Leucopsarion petersi using otolith microchemistry analysis. Both species were collected along the Sanriku Coast. Otolith Sr : Ca ratios of ayu fluctuated strongly along the life history transect in accordance with the migration (habitat) pattern from fresh water to sea water. The Sr : Ca ratios of the center region averaged 3.2 × 10−3 ; thereafter, the ratios increased sharply, averaging 9.2 × 10−3 , and were maintained at the higher levels until the outermost regions. By contrast, the Sr : Ca ratios of ice goby showed consistently high values along the life history transect of the otolith, ranging 9.0 × 10−3 in the center to 9.2 × 10−3 in regions outside the center, with further increases around the otolith edge. These findings indicate that ayu shows a typical amphidromous migratory pattern, while ice goby does not show the anadromous migratory pattern previously reported. The use of a freshwater environment during the early developmental stage in ice goby along the Sanriku Coast was less prominent than that of ayu in the same region. 相似文献
8.
We propose the concept of a pooling fishery system with a competitive sharing rule as a remedy for the tragedy of the commons
without the need to consider the free-riding problem or dissatisfaction of more skillful or eager members. Each fisherman
receives his share of pooled income according to his level of achievement, relative to those of other members, of pre-agreed
common objectives such as the conservation of depleted stocks. After analyzing the system using the game theoretic approach,
we examine its performance as a fisheries management system using a computer simulation. In our example, this system was proven
to suppress increases in fishing effort by game theoretic interactions among fishermen, to maintain the stock size at a high
level, and to increase the average fishing income. Although there is still much scope for improving this system for practical
use, the concept of this system has the potential to contribute to the attainment of sustainable fisheries management. 相似文献
9.
Yuta NAGAI Takeharu KANEDA Yasuyuki MIYAMOTO Takaomi NURUKI Hidenori KANDA Norimoto URAKAWA Kazumasa SHIMIZU 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2016,78(1):55-59
To elucidate the dependence of aerobic energy metabolism and utilization of glucose in
contraction of urinary bladder smooth muscle, we investigated the changes in the reduced
pyridine nucleotide (PNred) fluorescence, representing glycolysis activity, and determined
the phosphocreatine (PCr) and ATP contents of the porcine urinary bladder during
contractions induced by high K+ or carbachol (CCh) and with and without hypoxia
(achieved by bubbling N2 instead of O2) or in a glucose-free
condition. Hyperosmotic addition of 65 mM KCl (H-65K+) and 1
µM CCh induced a phasic contraction followed by a tonic contraction. A
glucose-free physiological salt solution (PSS) did not change the subsequent contractile
responses to H-65K+ and CCh. However, hypoxia significantly attenuated
H-65K+- and CCh-induced contraction. H-65K+ and CCh induced a
sustained increase in PNred fluorescence, representing glycolysis activity. Hypoxia
enhanced H-65K+- and CCh-induced increases in PNred fluorescence, whereas
glucose-free PSS decreased these increases, significantly. In the presence of
H-65K+, hypoxia decreased the PCr and ATP contents; however, the glucose-free
PSS did not change the PCr contents. In conclusion, we demonstrated that high
K+- and CCh-induced contractions depend on aerobic metabolism and that an
endogenous substrate may be utilized to maintain muscle contraction in a glucose-free PSS
in the porcine urinary bladder. 相似文献
10.
Madoka Ohji Takaomi Arai Sayaka Midorikawa Hiroya Harino Reiji Masuda Nobuyuki Miyazaki 《Water, air, and soil pollution》2007,178(1-4):255-265
In order to elucidate the details of both the distribution and fate of organotin compounds (OTs) in the costal ecosystem, the concentrations of butyltin compounds (BTs) and phenyltin compounds (PTs) were determined in seawater, sediment and blue mussels Mytilus galloprovincialis collected in Maizuru Bay, Japan. The concentrations of tributyltin (TBT) in seawater, sediments and mussels ranged from 3.9 to 27 ng l?1, from 1.2 to 19 ng g?1 dry wt and from 0.77 to 11 ng g?1 wet wt, respectively. Although the levels of TBT in seawater, sediments and mussels from Maizuru Bay were lower than those reported previously at other sites in Japan, the levels can still be toxic to susceptible organisms. Trace amounts of PTs were also found in seawater, sediment and mussel samples, indicating that there is a slight input of triphenyltin (TPT) into the seawater in the bay at present. The highest TBT concentration in seawater among all sites measured in the bay was found near a glass factory, and the lowest concentrations were observed at the center of the bay. The highest concentration of TBT in sediment was detected near a shipyard. In mussels, a high concentration of TBT was detected near a cement plant and timberyard. These results indicate that the major sources of contamination of OTs in the bay are considered to be from those facilities and ships. The proportion of TBT in seawater and mussels showed that, of total BTs, it was the predominant compound at most sites. These results suggested that there is a continuous input of TBT into the seawater and thereafter an accumulation of TBT in mussels due to their low metabolic capacity to degrade TBT. In sediment, the proportion of monobutyltin (MBT) was the highest of BTs at most sites. This could reflect a previous contamination by TBT used before the regulation of its usage in the bay. 相似文献