Southern Kyushu Research Articles

Yield, silage quality, and feeding preference of late‐summer sown pearl millet (Cenchrus americanus (L.) Morrone) in Southern Kyushu

AbstractBackgroundPearl millet is characterized by its high dry matter (DM) yields with a high moisture content, which makes it difficult to process as silage.MethodsPearl millet was sown in mid‐September for 3 years to examine its growth, DM yields in early December, and decrease in DM percentage after frost exposure. The crop was processed as round‐bale silage to assess silage quality and preference by breeding beef cattle.ResultsPlants reached a height of 160–200 cm, with heading tiller percentages of 50%–70% in early December. With frost exposure, DM percentage increased in leaves and panicles, followed by stems, reaching over 40%, 1 month after exposure. These increases were positively correlated with cumulative frost exposure. After frost exposure, in vitro DM digestibility and crude protein content declined while acid detergent fiber content increased. Repeated cafeteria feeding experiments showed a reduced preference for either pearl millet silage or Italian ryegrass hay. The silage showed moderate acidity at pH 4.73–5.40, with lactic acid at 0.58%–1.62% DM, acetic acid at 0.03%–0.10% DM, and negligible butyric acid, indicating a satisfactory quality.ConclusionsIn Southern Kyushu, pearl millet sown in late summer can be processed into low‐moisture round‐bale silage in January, the year following sowing.

Major Holocene cryptotephras layers identified from Jeju Island, Republic of Korea: Implications for regional volcanic eruptions and environmental changes

Cryptotephras recorded in sediments are valuable isochrons with which to reconstruct volcanic eruptive history and synchronize environmental changes across large regions. Here we identify four cryptotephras from Jeju Island, Republic of Korea, that constitute tie-points linking palaeoenvironmental records of tropical to mid-latitude east Asia. A cryptotephra of unknown source with trachytic glass compositions at around 2700 cal a BP (named M263a) can be correlated with the HGY263 recorded in the Huguangyan Maar lake in southern China, and SG14–0433 recorded in Suigetsu lake in central Japan. Another population of glass shards with basaltic andesitic to trachybasaltic composition (named M263b) represents the first cryptotephra record of a Jeju eruption. A rhyolitic cryptotephra at ∼7384 cal a BP (H53) can be correlated with the ∼7.3 ka Kikai-Akahoya eruption (specifically, the K-Ah tephra) from Kikai caldera, southern Kyushu, Japan. The cryptotephra coincides with a marked change in aquatic algae communities in Jeju sediments, possibly signifying a climate response to the eruption. Additionally, cryptotephra layers at ∼6948 cal a BP (H22) in the Hanon Maar Lake and ∼ 1030 cal a BP (M125) in Mulyoungari wetland exhibit similar glass compositions to those of the K-Ah tephra, which suggests they are the product of unknown eruptions from Kikai or a neighboring volcano. Given the widespread distributions of K-Ah and M263a tephra across east Asia, Jeju sediments can be precisely synchronized with those high-resolution sediments from southern China and Japan, providing two Holocene marker horizons for palaeoenvironmental comparisons across east Asia. Our work shows great promise for the improved chronological constraints and inter-site linkages for palaeoenvironmental sequences in the region through the application of tephrochronology.

Effects of Establishment on Growth, Yield, and Silage Qualities of Amaranth in Typhoon-Prone Southern Kyushu, Japan

Effects of Establishment on Growth, Yield, and Silage Qualities of Amaranth in Typhoon-Prone Southern Kyushu, Japan

Structure and Maintenance of a Quasi-Linear Mesoscale Convective System That Caused Torrential Rain in Southern Kyushu, Japan, on 11 July 2021

Abstract A quasi-linear mesoscale convective system that remained nearly stationary (hereafter referred to as a stationary QLCS) for almost 8 h in southern Kyushu, Japan, caused torrential rainfall exceeding 350 mm on 11 July 2021. The stationary QLCS consisted of several rainbands organized by back-building convection. As the cold pool intensified, the system attained a more widespread structure, leaning on the upshear side. To elucidate the mechanism responsible for the upshear tilt, numerical simulations with 250-m horizontal grid spacing were conducted, including sensitivity experiments in which the evaporative cooling rates from rain were reduced to modify the cold pool intensity. Results show that the cold pool is critical to the organization of the QLCS, and the structure normal to it is mainly governed by the balance between the low-level shear magnitude and cold pool intensity, supporting the application of so-called Rotunno–Klemp–Weisman (RKW) theory to this event. The cause of the weak updraft that accompanies the leaning system over the strong cold pool was also investigated, analyzing the trajectories, vertical momentum equation, and pressure perturbation field using the anelastic equation. It is revealed that the updraft travels a longer distance through the tilted system experiencing more mixing with the ambient air, which results in less thermal buoyancy. In addition, the updraft is decelerated by the downward perturbation gradient force owing to the vertical buoyancy gradient around the sloping surface of the cold pool and the dynamical effect caused by the baroclinicity-associated strong horizontal vorticity around the cold pool leading edge.

Intraspecific divergence in a coastal plant, Euphorbia jolkinii, at a major biogeographic boundary in East Asia.

Quaternary climatic fluctuations and long-distance seed dispersal across the sea are critical factors affecting the distribution of coastal plants, but the spatiotemporal nature of population expansion and distribution change of East Asian coastal plants during this period are rarely examined. To explore this process, we investigated the genome-wide phylogenetic patterns of Euphorbia jolkinii Boiss. (Euphorbiaceae), which grows widely on littoral areas of Japan, Korea, and Taiwan. We used plastome sequences and genome-wide single nucleotide polymorphisms in samples across the species range to reveal phylogeographic patterns and spatiotemporal distributional changes. We conducted ecological niche modeling for the present and the last glacial maximum (LGM). Genetic differentiation was observed between the northern and southern populations of E. jolkinii, separated by the major biogeographic boundary, the Tokara Gap. These two groups of populations differentiated during the glacial period and subsequently intermingled in the intermorainic areas of the central Ryukyu Islands after the LGM. Ecological niche models suggested that the potential range of E. jolkinii was restricted to southern Kyushu; however, it was widespread in the southern Ryukyu Islands and Taiwan during the LGM. This study provides evidence of genetic differentiation among coastal plant populations separated by the prominent biogeographical boundary. Although coastal plants are typically expected to maintain population connectivity through sea-drifted seed dispersal, our findings suggest that genetic differences may arise because of a combination of limited gene flow and changes in climate during the glacial period.

Field‐based description of near‐surface crustal deformation in a high‐strain shear zone: A case study in southern Kyushu, Japan

AbstractThis study investigated geological evidence for near‐surface crustal deformation in a high‐strain shear zone that has been geodetically identified but which is not associated with obvious tectonic landforms. Fieldwork was conducted in the east–west‐trending southern Kyushu high‐strain shear zone (SKHZ), Japan, focusing mainly on occurrences of fracture zones, which are defined by a visible fracture density of >1 per 10 cm2 and are commonly associated with cataclasite, fault breccia, and gouge. The area in which east–west‐trending fracture zones are dominant is restricted to the east–west‐trending, ~2‐km‐wide aftershock area of the 1997 Northwestern Kagoshima Earthquakes. Analysis of slip data from minor faults using the multiple inverse method, irrespective of whether the faults are in fracture zones, reveals that the area where the calculated main stress field is consistent with the current stress field estimated from focal‐mechanism solutions of microearthquakes is restricted to the east–west‐trending aftershock area. This finding for the SKHZ contrasts with the case of the Niigata–Kobe Tectonic Zone, which is a major strain‐concentration zone with many exposed active faults in central Japan and for which the stress field estimated using fault‐slip data is considered to be uniform and coincides with the current stress field. The cumulative amount of displacement estimated from the areal density of fracture zones in the SKHZ study area is smaller than that estimated from geodetically measured strain rates. Investigations based on slip data from minor faults and fracture‐zone occurrence could help to identify concealed faults that are too small to generate tectonic landforms but which are sufficiently large to trigger major earthquakes.

Allophanes in the weathered volcanic ash deposits distributed in southern Kyushu, Japan and their ion adsorption characteristics

Allophanes in the weathered volcanic ash deposits distributed in southern Kyushu, Japan and their ion adsorption characteristics

Ecological niche modeling shed light on new insights of the speciation processes and historical distribution of Japanese fire-bellied newt Cynops pyrrhogaster (Amphibia: Urodela)

Environmental factors play vital roles in determining the range of organisms and application of selective pressures that drive their evolution. Investigation of how these ecological factors influence the diversification of species has long been a point of interest among ecologists. In this study, we used climate-based ecological niche models to project the suitable distributions of four main clades of Japanese fire-bellied newt Cynops pyrrhogaster at the Last Glacial Maximum (LGM), Mid-Holocene (MH), and the present. Then we tested hypotheses regarding ecological niche diversification and the processes of diversification among these clades. The potential distribution of the Northern clade encompassed the Tohoku and Kanto districts, along with the northeastern Chubu district. The Central clade had a potential distribution across the Chubu and Kinki districts, and northeastern Chugoku district. The range of the Western clade was projected to encompass Kyushu, Shikoku, the southern Kinki region, and western Chugoku. Finally, the projected distribution of the Southern clade was limited to the southern Kyushu district. The lack of equivalent niches among the tested pairs indicated the absence of ecological interchangeability among the clades. The results of a similarity test supported significant parapatric divergence of the Northern and Central clades from the remaining clades. On the other hand, the Western and Southern clades probably underwent divergence through an allopatric process. Our paleomodels suggest that the distribution of C. pyrrhogaster may have been reduced and fragmented along the coastal regions during the LGM. The distribution models for the MH estimated a suitable area larger than for the LGM, but smaller than predicted by the current distribution. Our findings serve as a warning that the potential distributions of species could be significantly influenced by future climate change.

Dispersal and grain size characteristics of the May 14, 2018 Shinmoedake eruption deposit, Kirishima Volcano, Japan, based on post-eruption field survey and meteorological datasets

This study describes the dispersal and grain size characteristics of the May 14, 2018 Shinmoedake eruption deposits of Kirishima Volcano in southern Kyushu, southwestern Japan. We discuss the eruption sequence, including the temporal variations in the behavior of the plume, by combining field and meteorological datasets. Following a magmatic activity in 2011 characterized by a substantial change in the eruption style (from subplinian eruptions to lava effusion) and subsequent vulcanian explosions, the Shinmoedake crater experienced intermittent eruptions in 2018. The May 14, 2018 eruption began at 14:44 with a vulcanian eruption, with the eruption plume rising 4500 m above the crater rim. Thereafter, it transitioned to an ash eruption; the plume height decreased gradually until the eruption ceased at 16:10. The tephra fall deposits were distributed more than 27 km to the southeast of the source crater; the mass of the tephra fall deposit was approximately 2.1 × 107 kg, calculated based on an isomass map. The deposit incidence differed between the east and west sides of the major dispersal axis. The deposits found east of the main dispersal axis were primarily composed of coarse to medium sand-sized particles with no fine fraction (fine sand to silt in size). In contrast, the deposits west of the axis were finer-grained than those east of the axis. We analyzed photographs of the eruption plume, along with the regional meteorological data and the dispersal and grain-size characteristics of the deposits, and reached the following conclusion: during the May 14, 2018 eruption, the wind directions above the Shinmoedake crater fluctuated across altitudes. The westerly winds dispersed the eruption plume that rose to a higher altitude, containing coarser tephra associated with the initial vulcanian eruption, further to the east rather than along the main axis. In contrast, a lower-altitude ash eruption plume that was rich in fine materials was dispersed westward rather than along the main axis, which was influenced by northerly winds. The findings of this study can support the analysis of similar volcanic events.Graphical

Notable Clinical Differences Between Neonatal and Post-Neonatal Intestinal Malrotation: A Multicenter Review in Southern Japan

BackgroundMost cases of intestinal malrotation appear in neonates with bilious vomiting due to midgut volvulus, whereas in cases that develop beyond infancy, the initial symptoms vary. This study investigated the clinical features of these two populations and identified issues that should be considered in daily practice. MethodsA retrospective chart review was conducted from January 1, 2010, to December 31, 2022. Data on patients with intestinal malrotation were collected in an anonymized fashion from five pediatric surgical hub facilities in the Southern Kyushu and Okinawa areas of Japan. ResultsOf the 80 subjects, 57 (71.3%) were neonates (Group N) and 23 (28.7%) were infants and schoolchildren (Group I). The frequencies of initial symptoms, such as abdominal distention (Group N: 19.3% vs. Group I: 13.0%), bilious vomiting (59.6% vs. 43.5%), and hematochezia (8.8% vs. 21.7%), were not skewed by the age of onset (p = 0.535, 0.087, and 0.141, respectively). Midgut volvulus was significantly more frequent in Group N (71.9% [41/57] vs. 34.8% [8/23]; p = 0.005), while the degree of torsion was greater in group I (median 360° [interquartile range: 180–360°] vs. 450° [360–540°]; p = 0.029). Although the bowel resection rate was equivalent (7.0% [4/57] vs. 4.3% [1/23]; p = 1.000), half of the patients in Group N presented with 180° torsion. The neonatal intestine has been highlighted as being more susceptible to ischemia than that in older children. ConclusionsThe incidence of midgut volvulus is higher in neonates than in older children. Even relatively mild torsion can cause ischemic bowel changes during the neonatal period. Level of EvidenceLEVEL III.

Solidified magma reservoir derived from active source seismic experiments in the Aira caldera, southern Kyushu, Japan

The Aira caldera, located in southern Kyushu, Japan, originally formed 100 ka, and its current shape reflects the more recent 30 ka caldera-forming eruptions (hereafter, called the AT eruptions). This study aimed to delineate the detailed two-dimensional (2D) seismic velocity structure of the Aira caldera down to approximately 15 km, by means of the travel-time tomography analysis of the seismic profile across the caldera acquired in 2017 and 2018. A substantial structural difference in thickness in the subsurface low-velocity areas in the Aira caldera between the eastern and western sides, suggest that the Aira caldera comprises at least two calderas, identified as the AT and Wakamiko calderas. The most interesting feature of the caldera structure is the existence of a substantial high-velocity zone (HVZ) with a velocity of more than 6.8 km/s at depths of about 6–11 km beneath the central area of the AT caldera. Because no high ratio of P- to S-wave velocity zones in the depth range were detected from the previous three-dimensional velocity model beneath the AT caldera region, we infer that the HVZ is not an active magma reservoir but comprises a solidified and cool remnant. In addition, a poorly resolved low-velocity zone around 15 km in depth suggests the existence of a deep active magma reservoir. By superimposing the distribution of the known pressure sources derived from the observed ground inflation and the volcanic earthquake distribution onto the 2D velocity model, the magma transportation path in the crust was imaged. This image suggested that the HVZ plays an important role in magma transportation in the upper crust. Moreover, we estimated that the AT magma reservoir in the 30 ka Aira caldera-forming eruptions has the total volume of 490 km3 DRE and is distributed in a depth range of 4–11 km.Graphical

Soil erosion under forest hampers beech growth: Impacts of understory vegetation degradation by sika deer

The overpopulation of large herbivorous mammals degrades understory vegetation and hence promotes soil erosion in some northern hemisphere forests. Topsoil removal via erosion reduces soil water and nitrogen (N) content as well as exposes tree roots. However, whether topsoil removal inhibits tree growth through water and N uptake limitations has not been examined. This study aimed to measure the vertical length from exposed roots surface to the soil surface (exposed root height; ERH) under degraded forest understory vegetation and to evaluate its influence on tree growth. Specifically, we examined the relationships between ERH and beech growth and identified the timing of growth reduction based on annual tree-ring analysis at the individual scale. Furthermore, we discussed the effects of water and N limitations on beech growth reduction. We studied 12 Japanese beech trees on Mt. Sanpo, southern Kyushu Island, Japan, where understory vegetation was degraded and lost due to herbivory by Japanese sika deer from 1980 to 2003. Lower amounts of leaf production and relative growth rates of stem basal area increment (BAI) were observed in beech trees with higher ERH. Segmented regression analysis, which detects the changing time of a temporal trend (i.e., break-point), revealed that the BAI has resulted in a decreasing trend after 1997.6 ± 9.0 (yr), which coincided with the field observations on understory degradation in the study site. After the break-point of the BAI, the BAI of each study tree was negatively related to intrinsic water use efficiency, an integrated index of water limitation. These results suggest that soil erosion after the degradation of understory vegetation reduced beech growth, possibly because of the water limitations associated with root exposure. Reduced beech growth will reduce the supply of the litter layer that prevents topsoil erosion, which may enhance further soil erosion and tree growth reduction.

The effects of the different sowing methods and planting density on the yield components of soybean (Glycine max) under intercropping condition with rhodes grass (Chloris gayana Kunth.)

In Japan, grass-legume intercropping systems are being developed to increase quality and yield of grain and forage. Hence, this study evaluated the effects of sowing methods and planting density on yield traits of forage soybean under intercropping condition with rhodes grass. The field experiment was laid on in a completely randomized block design with four treatments and four replications. Rhodes grass seeds were sown at 2.8 kg/10a in a field containing mono- and intercropping-plots. For soybeans, two levels of sowing densities (about 15 or 30 seeds/m2: named “L” and “H”) and two sowing methods (row or spray: named “R” and “S”) were applied for a total of four different intercropping combinations. Rhodes grass DMY obtained the highest in low level of sowing density with rowing methods (LR) (338 kg/10a) while soybean DMY obtained the highest in high level of sowing density with rowing methods (HR) (251 kg/10a) and in high level of sowing density with spray methods (HS) (177 kg/10a). Intercropping at low density increased CP (12%) and CPY (40.4 kg DM/10a) in Rhodes grass, and CP (18.9%) in soybeans, whereas high sowing density increased soybean CPY in HR (41.5 kg DM/10a) and contributed to higher soybean CPY in DM percentage at 66% (HS) and 56% (HR). Overall, high density sowing increased the 1st total DMY while row sowing increased the 1st total CPY in both crops at the first cutting, while monocropping increased Rhodes grass yield and plant length at the second-cutting. Also, sowing soybean by a broadcast spreader could obtain sufficient crude protein yield as a forage soybean in southern Kyushu, Japan. Further studies are needed for soybean overseeding method and use of early-maturity soybean lines

Influence of a low viscosity zone on the evolution of post-eruption deformation: A case study of the crustal deformation of Aira Caldera after the 1914 eruption of Sakurajima Volcano

Spatial viscosity variations in the crust can be inferred from geophysical imaging and may be essential for interpreting volcano deformations that show more complex behaviours than what simple uni-viscous models predict. In southern Kyushu, Japan, recent seismic imaging implies the presence of a low viscosity zone (LVZ) beneath Aira Caldera, and geodetic data in and around the caldera require uni-viscous model to have lower and higher viscosities earliest and later, respectively, in the period following the 1914 eruption of Sakurajima Volcano. Here, we use a 3D finite element model comprising an elastic layer underlain by a linear Maxwell viscoelastic layer to examine the influence of a LVZ on ground surface displacement in response to two different deformation source modes, i.e., instantaneous source deflation during a major eruption and subsequent continuous source inflation due to magma recharge. A LVZ is introduced into the viscoelastic layer by gradually reducing its viscosity towards the centre. The behaviour of the LVZ model quantified by comparison with the behaviour of a uniform viscosity (UNV) model reveals that, for a given LVZ structure, an apparent UNV model that best represents the LVZ model displacement in response to the instantaneous deflation has lower viscosity than that in response to gradual inflation, i.e., the rate-controlling viscosities of the LVZ model are those in the inner and outer parts of the LVZ for the instantaneous source deflation and subsequent continuous inflation, respectively. Such LVZ model behaviour, for a LVZ spatial extent comparable with the imaged low velocity anomaly, explains well the geodetic data in and around Aira Caldera at any stage after the 1914 eruption, as the predominant viscoelastic response changes with time from that to the instantaneous deflation to that to the subsequent continuous inflation. This study highlights the need for interdisciplinary investigations that integrate geodetic and geophysical datasets to better understand volcanic unrest.

Soil erosion decreases soil microbial respiration in Japanese beech forests with understory vegetation lost by deer

ABSTRACT Increases in the number of wild herbivores resulted in understory degradation because of their overgrazing in forest ecosystems. Deer overgrazing has occurred soil erosion in Japanese beech forests where dwarf bamboo used to be densely covered. Soil erosion can result in a decrease in soil carbon and nutrient contents, causing the soil microbial respiration in such forest ecosystems to be degraded. The objective of this study was to clarify the effects of soil erosion, which sporadically occurs within the forests, on soil properties and microbial activity. Soil erosion indices, such as the maximum height of exposed roots from the soil surface (MAXH), tree and soil properties, microbial basal and substrate-induced respiration, were measured under the canopy of 16 beech trees in each of three deciduous broadleaved forests on southern Kyushu Island, Japan. Soil properties such as the humus mass and the organic matter contents of soil and humus decreased with MAXH. Basal and substrate-induced respiration decreased with increases in MAXH. Soil properties associated with organic matter increased with basal and substrate-induced respiration. These results suggest that soil surface layers that were rich in organic matter ran off because of soil erosion, resulting in the degradation of soil microbial activity. This study suggests that increases in wild herbivore populations degrade soil ecosystem functioning owing to the soil erosion induced by understory disappearance.

Preliminary assessment of genetic variation in the Japanese endemic freshwater crab, Geothelphusadehaani, based on mitochondrial DNA sequences.

Geothelphusadehaani, a freshwater crab species endemic to Japan, has the largest distribution range amongst the 19 known species in the country. Due to its low dispersal capability and restricted habitat to freshwater, it serves as an excellent model for understanding gene flow between geographically isolated populations. In this study, we analysed the genetic relationships of 26 G.dehaani populations collected from different locations in the Japanese archipelago using two mitochondrial DNA regions - cytochrome oxidase subunit I (COI) and cytochrome b (cytB). Our results from the analysis of molecular variance (AMOVA) revealed high genetic variation amongst populations and the phylogenetic analysis identified four geographical groups: Clade I - Honshu and Shikoku, Clade II - north-eastern Kyushu, Clade III - southern Kyushu and Clade IV - north-western Kyushu. Notably, Clade IV exhibited the highest genetic distance amongst the observed groupings. These findings highlight the need for further examination of G.dehaani in Kyushu, including morphological and behavioural traits, to better understand the observed diversity within the species in the region.

Arable and Livestock Corporation Trial in the Upland Fields of the Southern Kyushu Region:

Arable and Livestock Corporation Trial in the Upland Fields of the Southern Kyushu Region:

Natural attenuation and remobilization of arsenic in a small river contaminated by the volcanic eruption of Mount Iou in southern Kyushu Island, Japan

The active volcano Mount Iou, in the southern part of Japan, erupted in 2018 for the first time in approximately 250 years. Geothermal water discharged from Mount Iou had high concentrations of toxic elements, such as arsenic (As), which could seriously contaminate the adjacent river. In this study, we aimed to clarify the natural attenuation of As in the river through daily water sampling for approximately eight months. The risk of As in the sediment was also evaluated using the sequential extraction procedures. The highest As concentration (2000 μg/L) was observed upstream but typically remained below 10 μg/L downstream. Dissolved As was the main form in the river water on non-rainy days. Arsenic concentration in the river naturally decreased through dilution and sorption/coprecipitation with Fe, Mn, and Al (hydr)oxides during flow. However, peaks in As concentration were frequently observed during rainfall events, possibly due to sediment resuspension. Furthermore, the range of pseudo-total As in the sediment was 4.62–14.3 mg/kg. Total As content was highest upstream before decreasing further along the flow. When using the modified Keon method, 44–70% of the total As existed as more reactive fractions associated with (hydr)oxides.

Fine Particle Adsorption Capacity of Volcanic Soil from Southern Kyushu, Japan.

"Akahoya" is a volcanic soil classified as a special soil deposited in Kyushu, Japan. Many of its properties are not yet clearly understood. We found that Akahoya had the potential to adsorb bacteria in cattle feces, which prompted us to investigate its material properties and perform experiments to comprehensively evaluate its adsorption performance for various fine particles such as acidic and basic dyes, NOx/SOx gas, and phosphoric acid ions, in addition to bacteria. Akahoya had a very high specific surface area owing to the large number of nanometer-sized pores in its structure; it exhibited a high adsorption capacity for both NO2 and SO2. Regarding the zeta potential of Akahoya, the point of zero charge was approximately pH 7.0. The surface potential had a significant effect on the adsorption of acidic and basic dyes. Akahoya had a very high cation exchange capacity when the sample surface was negatively charged and a high anion exchange capacity when the sample surface was positively charged. Akahoya also exhibited a relatively high adsorption capacity for phosphoric acid because of its high level of Al2O3, and the immersion liquid had a very high Al ion concentration. Finally, filtration tests were performed on Escherichia coli suspension using a column filled with Akahoya or another volcanic soil sample. The results confirmed that the Escherichia coli adhered on the Akahoya sample. The results of the Escherichia coli release test, after the filtration test, suggested that this adhesion to Akahoya could be phosphorus-mediated.

A comparison of the swimming behavior of greater amberjack <i>Seriola dumerili</i> in southern Kyushu and eastern Taiwanese waters

薩南海域におけるカンパチ成魚の遊泳行動を取得し，台湾東部海域の既往知見と比較した。薩南海域の個体は台湾東部の個体よりも移動範囲が狭く，放流した海域の近傍に留まり続けていた。海域間で滞在深度は異なっていたが経験水温は同程度であった。核DNAのITS領域とmtDNAのcytochrome b領域の塩基配列情報を用いて標識個体の種判別を試みたところ，形態的にはカンパチであるにも関わらず，ヒレナガカンパチと同様のcytochrome b領域のPCR-RFLPパターンを示す個体が見られた。