Top PDF Growth and habitat residence history of migrating silver American eels transplanted to Taiwan.

Growth and habitat residence history of migrating silver American eels transplanted to Taiwan.

Growth and habitat residence history of migrating silver American eels transplanted to Taiwan.

This study compares growth performance and migratory behavior, using otolith stron- tium (Sr)/calcium (Ca) ratios of those six American eels with cohabitating Japanese eels and American eels in North America. Regardless of sex, mean age at maturity of the exotic American eels was greater and mean annual growth rate was less than that of Japanese eels in Taiwan and similar to that of American eels in the southern United States. Sr/Ca ratios at the otolith edge of the six exotic American eels, which recorded their salinity history, increased significantly. Furthermore, four of the six exotic Ameri- can eels spent more than one year in the high-salinity estuary. Their extended residence in the estuary may be due to a delayed spawning migration resulting from a failure to orientate and migrate properly to their native spawning site.
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Variation in the annual growth, by sex and migration history, of silver American eels Anguilla rostrata

Variation in the annual growth, by sex and migration history, of silver American eels Anguilla rostrata

2 Institute of Zoology, and 3 Institute of Earth Sciences, Academia Sinica, Nankang, Taipei, Taiwan 11529, ROC 4 Institute of Fisheries Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan 10617, ROC ABSTRACT: Silver American eels Anguilla rostrata from the East River, Chester, on the Atlantic coast of Nova Scotia, as evaluated by the temporal pattern of Sr:Ca ratios in their otoliths, showed variable patterns of migration between river and estuarine/marine waters during their yellow eel stage. Eels with a history of primarily estuarine residence were longer (total length) at migration and had higher annual growth rates than did eels with a primarily freshwater residence. Female eels were longer at migration and had higher annual growth rates than did males. The percentage (64%) of silver eels with a history of estuarine residence and their larger size at age, size at migration, and higher growth rate relative to freshwater resident eels may result from higher productivity in oceanic than fresh- waters at higher latitudes, as modified by regional environmental conditions. Environmental condi- tions change with increasing latitude in a different pattern for American and Japanese eels than for European eels.
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Migratory behaviour and habitat use by American eels Anguilla rostrata as revealed by otolith microchemistry

Migratory behaviour and habitat use by American eels Anguilla rostrata as revealed by otolith microchemistry

in Sr:Ca ratios to below 4.0 × 10 – 3 or above 5.0 × 10 – 3 were readily interpreted, but extended fluctuations about these values were problematic. They perhaps reflected a series of quick movements between estuary and river or residence in the river-influenced upper estuary, in conjunction with the physiological lag in incorporating into the otolith the evidence of a habitat shift. However, it is puzzling why 41% of the silver eel total had Sr:Ca ratios greater than 4.5 × 10 – 3 at the otolith edge, which suggests estuarine residence, when they were collected in freshwater 1.3 km up- stream from the river mouth and migrating down- stream. Several hypotheses can be proposed: (1) the results are an artefact of otolith preparation and analy- sis; (2) shortly, perhaps a year, before silvering, estuar- ine-resident eels re-entered the river for a brief (no evidence of freshwater residence was yet evident in the otoliths) period of freshwater residence before migrating downstream as silver eels; and (3) once in the river, the eels had remained there and the variation in Sr:Ca ratio was due to varying environmental condi- tions in the river, such as low pH, the annual liming of one tributary of the river between 1986 and 1996 or variable annual growth rates.
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Effects of inter-habitat migration on the evaluation of growth rate and habitat residence of American eels Anguilla rostrata

Effects of inter-habitat migration on the evaluation of growth rate and habitat residence of American eels Anguilla rostrata

fwg) groups, respectively, to their next higher groups when based on residence time. Thus, otolith growth proportion was again found to be basically equivalent to habitat residency proportion. However, where the growth rate differences between habitats are much higher than those observed here, such as for American eels from Prince Edward Island (Lamson 2005), biolog- ically and analytically important differences may occur between otolith growth proportion and habitat resi- dency period. The close match of the habitat residence model with the observed data suggests that the model may be usefully applied to predict the relationship between otolith growth and habitat residence period for yellow and silver eels, with mean growth rates sim- ilar to those observed in this study, but it requires fur- ther verification for higher mean growth rates.
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Life history of american eels from Western Newfoundland

Life history of american eels from Western Newfoundland

to their positive relation with TL, but comparison with eels of similar size show index differences that are sufficiently large to be real. A progressive increase also occurs in maturation indices (GSI, EI, and PFI) during migration, with consequent effect on the comparison of maturation indices among sites due to the timing of sampling. Minor differences in index values, particu- larly GSI, may result from different methods of estimation among studies. A lower degree of sexual maturation at the onset of the spawning migration in more northerly eel stocks and the additional develop- mental period available during their longer marine migration may permit fish from different latitudes to reach the spawning ground at approximately similar times and reproductive condition (Wenner 1973;
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Differences in size and growth rates of male and female migrating Japanese eels in Pearl River, China

Differences in size and growth rates of male and female migrating Japanese eels in Pearl River, China

(Sun Yet-Sen) University, Guangzhou 510275, PROC (Received 13 January 2000, Accepted 21 June 2000) The Sr/Ca ratios in otoliths of silver Japanese eels Anguilla japonica in Pearl River, China, indicated that both sexes did not stay in brackish water and grew in fresh water from the glass eel stage until spawning migration. This did not support the hypothesis that females tended to distribute upstream and males might be restricted to estuaries. The back-calculated total length of males at glass eel stage was not significantly different from that of females, indicating that the hypothesis that small glass eels became males and larger ones became females may not be true.
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Differences in size and growth rates of male and female migrating Japanese eels in Pearl River, China.

Differences in size and growth rates of male and female migrating Japanese eels in Pearl River, China.

(Sun Yet-Sen) University, Guangzhou 510275, PROC (Received 13 January 2000, Accepted 21 June 2000) The Sr/Ca ratios in otoliths of silver Japanese eels Anguilla japonica in Pearl River, China, indicated that both sexes did not stay in brackish water and grew in fresh water from the glass eel stage until spawning migration. This did not support the hypothesis that females tended to distribute upstream and males might be restricted to estuaries. The back-calculated total length of males at glass eel stage was not significantly different from that of females, indicating that the hypothesis that small glass eels became males and larger ones became females may not be true.
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The swimbladder parasite Anguillicola crassus in native Japanese eels and exotic American eels in Taiwan

The swimbladder parasite Anguillicola crassus in native Japanese eels and exotic American eels in Taiwan

(Accepted April 30, 2008) Yu-San Han, Ya-Ting Chang, Horst Taraschewski, Su-Ling Chang, Che-Chun Chen, and Wann-Nian Tzeng (2008) The swimbladder parasite Anguillicola crassus in native Japanese eels and exotic American eels in Taiwan. Zoological Studies 47(6): 667-675. To understand differences in infection patterns of the swimbladder parasite Anguillicola crassus between habitats and eel species in Taiwan, the prevalence and intensity of the parasite were examined based on specimens collected from wild and cultured Japanese eel Anguilla japonica and from exotic cultured American eel A. rostrata in the Kaoping River and culture ponds in southwestern Taiwan in 2006-2007. The prevalence of Aco. crassus in wild Japanese eels was lower in winter compared with summer/autumn, varying 33%-58%, with a mean intensity of 1.5-4.4. The prevalence and intensity were size- dependent and increased with eel size. In cultured Japanese eels, the prevalence and mean intensity varied greatly at 3%-68% and 1.0-29.0, respectively. In cultured American eels, the prevalence and intensity were very high in ponds without drug treatment. In contrast to wild eels, the mean intensity of larval and adult worms showed a size-dependent decreasing trend in cultured eels. The mean body mass of Aco. crassus in American eels was significantly larger than that in Japanese eels. The external morphology, condition factor, and hepatosomatic index showed no significant differences between infected and uninfected groups, indicating a low pathogenic effect of Aco. crassus on these 2 eel hosts. Our results showed that both native Japanese eels and naive American eels are highly susceptible to Aco. crassus, but it causes little pathogenicity under good pond management. http://zoolstud.sinica.edu.tw/Journals/47.6/667.pdf
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Otolith Sr:Ca and Ba:Ca may give inconsistent indications of estuarine habitat use for American eels (Anguilla rostrata)

Otolith Sr:Ca and Ba:Ca may give inconsistent indications of estuarine habitat use for American eels (Anguilla rostrata)

When a suction hood is subject to the action of a cross draft, a half Rankine body of revolution (22) is formed. The dividing streamline evolves from an area far upstream, goes through the central axis at an intersection, rises up, then hits the lower surface of the downstream wing of flange perpendicularly to form a stagnation point if the cross draft to suction velocity ratio R is larger than a certain value. For instance, at the flange width to hood diameter ratio W /D = 2.5, the stagnation point would be formed on the lower surface of the flange if R > 0.075. At W/D = 3.0, the value of R must be greater than 0.048 so that the stagnation point is formed on the flange surface. In the upper left part of the dividing streamline, all the streamlines evolving from upstream area lead eventually to the hood opening and construct a capture envelope. The- oretically, all the contaminants inside the capture envelope should follow the flow and be drawn into the hood open- ing if the dispersion effect is ignored. The capture envelope shrinks in size with the increase of the velocity ratio R. All the measured results of the normalized distance between the stagnation point on the flange and the central axis, η/D, as well as the normalized distance from the origin to the intersection of hood centerline and dividing streamline, ς/D, follow the following equations that were obtained by Huang et al. (22) if the dividing streamline hits the flange perpendicularly and the stagnation point is located on the lower surface of the flange.
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History of vegetation and habitat change in the Austral-Asian region

History of vegetation and habitat change in the Austral-Asian region

This situation is likely to be a result of a combination of factors including the limited representation and re- stricted distribution of temperature controlled rainforest taxa, the dominance of sclerophyll and herb taxa containing a number of species with different and often wide bioclimatic ranges, little topographic variation and environments more exposed to incursions of sub- tropical high pressure systems and therefore very sensitive to moisture variation. The basalticwestern plains of Victoria have provided a focus for palynolo- gical research and vegetation variation is best illustrated by the Lake Wangoom record that covers the last two glacial cycles (Harle et al., 2002). Interglacials MIS 7, 5e and 1 show high values for forest or woodland taxa, especially Eucalyptus, while glacials are dominated by grasses and by herbaceous and shrubby members of the Asteraceae. Of the interglacials, MIS 5 is distinguished by its relative stability and high rainfall through the most notable representation of the rainforest taxon, Nothofagus, and tree ferns. There is no response of Casuarinaceae within this interglacial but the achieve- ment of high peaks within MIS 7, between those of Eucalyptus, indicate relatively high climatic variability at this time. In common with the many short pollen records from the area, the Holocene shows an initial peak of Casuarinaceae and later emergence of Eucalyp- tus. A different interglacial relationship between these two taxa is shown in the long but discontinuous and contentiously dated record from Lake George in the eastern highlands of New South Wales (NSW) (Singh and Geissler, 1985). Here, interglacials tentatively attributed to MIS 11, 9 and 7, are characterized by high values for Casuarinaceae, with Eucalyptus only becoming prominent and essentially replacing Casuar- inaceae within the last two interglacials. In contrast to almost all previous records examined, none from the mainland of southeastern Australia show clear re- sponses to the interstadials contained within MIS 5 suggesting that perhaps moisture sources were not greatly influenced by the relatively minor changes in temperature.
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Prevalence and intensity of occurrence of vaterite inclusions in aragonite otoliths of American eels Anguilla rostrata

Prevalence and intensity of occurrence of vaterite inclusions in aragonite otoliths of American eels Anguilla rostrata

Analyses of anguillid otolith Sr:Ca ratio transects have commonly been used to evaluate their residence and mi- gratory history between habitats of different salinity (Daverat et al. 2006, Jessop et al. 2008). Replicate, closely spaced Sr:Ca ratio transects produced close estimates of the proportion of freshwater residence for eels of largely estuarine residence, as required for the method to be useful. Although suitable transect paths for microchem- ical analysis may be found in highly vateritic otoliths, some otoliths may be entirely composed of vaterite and unsuitable for use. When an Sr:Ca ratio transect crossed vaterite inclusions, the proportion of freshwater resi- dence was greatly overestimated. Fortunately, the pres- ence of vaterite inclusions in otoliths is readily deter- mined and their intensity in American eel otoliths is typically small, reducing the potential bias in estimating habitat residence period; but if overlooked, the fre- quency of inter-habitat migration can be overestimated.
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Vertical habitat shift of viviparous and oviparous deep-sea cusk eels revealed by otolith microstructure and stable isotopic composition

Vertical habitat shift of viviparous and oviparous deep-sea cusk eels revealed by otolith microstructure and stable isotopic composition

(Received 22 July 2014, Accepted 12 November 2014) Otolith stable-oxygen-isotope composition and microstructure were analysed in order to investigate the vertical habitat shift of deep-sea cusk eels (Ophidiiformes). Otolith 𝛿 18 O profiles suggested that both viviparous blind cusk eels and oviparous cusk eels experienced a pelagic larval stage and then settled to the deep-sea floor over a vertical distance that ranged among individuals from 200 to >1000 m. This result shows that the larvae of viviparous Barathronus maculatus undertake an ontogenetic vertical migration after a period of larval drift that may facilitate their wide distribution on the sea floor.
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The sex ratios and growth strategies of wild and captive Japanese eels Anguilla japonica

The sex ratios and growth strategies of wild and captive Japanese eels Anguilla japonica

The role of gender and sexual differences in the growth histories of Japanese eel Anguilla japonica were linked with respect to the sex ratio and growth rate of wild eels collected from Taiwanese rivers. The sex ratio of wild eels was compared with that of eels semi-intensively cultured in a pond and intensively cultured in an aquarium. The sex ratio of wild eels from a low-density river habitat was dominated by females (86.4% of sex-determined eels), slightly dominated by males (57.1%) in a cultured pond, and dominated by males (90.0%) in an aquarium. This evidence supported the hypothesis that the sex of eels is determined by population density. The parameters of the von Bertalanffy growth equation demonstrated that males grew faster to reach a smaller asymptotic length than did females. We propose that the variation in eel sex ratio interacts with sex-linked differences in growth strategy to play an important role in density-dependent population regulation.
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Disease and Mortality in the History of Taiwan

Disease and Mortality in the History of Taiwan

Concluding remark This paper is a preliminary study on disease and death in the history of Taiwan prior to the era of health transition. With qualitative data gathered from various historical records, we have tried to provide a sketch of endemic and epidemic diseases suffered by the people of Taiwan since the seventeenth century. With some statistics available in the early twentieth century, we have tried to capture the health conditions of the Taiwanese and trace major causes of death. We have also touched upon some methods for preventing diseases, superstitious custom or effective medicine, social enforcement or epidemiological treatment, that have been adopted in Taiwan during the past few hundred years. Further studies are no doubt required for all these aspects and for details of specific diseases and their social, cultural and historical implications.
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HISTORY AND CURRENT STATUS  OF COURT INTERPRETING IN TAIWAN

HISTORY AND CURRENT STATUS OF COURT INTERPRETING IN TAIWAN

adversarial system – as versus the previous inquisitorial one – was very new in Taiwan, having only been implemented in April of 2004. Judges and lawyers have yet to acquire the techniques with the new procedures in order to mete out justice in a way they see fit. Subject D interviewed in this study said that although reforms are in

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Effect of Silver on the Sintering and Grain-Growth Behavior of Barium Titanate

Effect of Silver on the Sintering and Grain-Growth Behavior of Barium Titanate

A lighter-colored surface layer was observed on the silver- containing specimens. The vapor pressure of silver is high at temperatures above its melting point, 4 which resulted in a thin, silver-depletion surface layer after sintering. Both surface layers of the sintered disks were removed, first by grinding with SiC sandpaper, before any measurement. The specimens were buried in a pure ZrO 2 powder bed during sintering; therefore, this procedure also can remove the ZrO 2 diffusion layer. The final density was determined using the Archimedes method. The solubility of silver in BaTiO 3 is negligible (this observation will be demonstrated later); therefore, the theoretical density of the silver-doped BaTiO 3
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Manipulation of the Growth of Gold and Silver Nanomaterials on Glass by Seeding Approach

Manipulation of the Growth of Gold and Silver Nanomaterials on Glass by Seeding Approach

nanomaterials. We note that the spectra exhibited in Figure 5c and d both appear quite rough because of the poor resolution of the CCD. The differences between the single Ag and Au nanomaterials are further exhibited by the scattering intensities of the single NRs in different regions (Figure 6). The single Ag nanomaterials display different scattering intensities along their long axis, while those for Au nanomaterials are quite constant. The multicolor images for the single Ag nanomaterials are due to the different scattering properties (intensities and wavelengths) of single Ag nanomaterials of various widths; i.e., the many colors indicate the nonuniformity of the Ag nanomaterials with respect to their shape. The nonuniformity of these Ag nanomaterials supports our suggestion that formation of Ag nanomaterials is likely to occur through coalescence of several Ag nanomaterials. The aspect ratios of the NRs observed in the DFM images are smaller than these values measured through SEM imaging, mainly because the optically imaged width of a NR is diffraction limited. The diffraction-limited value is equal to ca. λ/2NA, where λ is the wavelength of the light and NA is the value of the numerical
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Observation of Growth of Human Fibroblasts on Silver Nanoparticles

Observation of Growth of Human Fibroblasts on Silver Nanoparticles

Observation of Growth of Human Fibroblasts on Silver Nanoparticles Hua-Chiang Wen a, * , Yao-Nan Lin a , Sheng-Rui Jian b , Shih-Chun Tseng a , Ming- Xiang Weng a , Yu-Pin Liu c , Po-Te Lee a , Pai-Yen Chen c , Ray-Quan Hsu a , Wen- Fa Wu c , and Chang-Pin Chou a

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Residence time of the Danshuei River estuary, Taiwan

Residence time of the Danshuei River estuary, Taiwan

Abstract The residence time of an estuary is defined in this study as the average time the initially existing water parcels reside in the system before they are flushed out. The residence time of the Danshuei River is calculated through a series of numerical experiments using a laterally integrated two-dimensional hydrodynamic eutrophication model (HEM-2D). The results show that the residence time is on the order of 1e2 days under the mean river flow to zero river flow condition, which is very short compared with most time scales of biogeochemical processes. A procedure is developed to quantify individual contribution to flushing by each of the three major physical transport mechanisms: tide, river discharge, and the density induced circulation. The results indicated that, in general conditions, tidal flushing exerts the greatest influence to the flushing of the Danshuei River estuary, while the density induced circulation hardly contributes any. Tidal transport contributes more than 50% of the flushing when river discharge is below its long- term mean. The suitability of applying the tidal prism method, the modified tidal prism methods, and the fraction of freshwater method in this estuary is also investigated. The relatively short residence time is likely to be one of the limiting factors that result in low phytoplankton biomass in spite of extremely high nutrient concentrations, and causes a significant fraction of pollutants to exert their effects in the coastal waters outside the estuary.
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Facultative catadromy in American eels: Testing the conditional strategy hypothesis

Facultative catadromy in American eels: Testing the conditional strategy hypothesis

3 Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan 106, ROC 4 Institute of Earth Sciences, Academia Sinica, PO Box 1-55, Nankang, Taipei, Taiwan 115, ROC 5 Institute of Oceanography, College of Science, National Taiwan University, Taipei, Taiwan 106, ROC ABSTRACT: Analyses of otolith strontium:calcium (Sr:Ca) ratios in 162 American eels Anguilla ros- trata of the St. Jean River watershed in eastern Canada demonstrated the co-existence of 6 migratory patterns, including freshwater and brackish water residence, and the predominance of an amphidro- mous migratory behavior. We tested the hypothesis that the choice of a particular life-history tactic may be controlled by a conditional strategy with status-dependent selection. This prediction was not supported because migratory patterns did not vary as a function of individual size, age and/or sex of eels prior to migration. However, we demonstrated that the utilisation of the estuarine brackish envi- ronment, more productive than the freshwater river and lake, resulted in a higher growth rate. Fresh- water yellow eels, the typical catadromous tactic, were rare and experienced lower growth rates.
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