Ise Bay Research Articles

Application of the WRF model to the coastal area at Ise Bay, Japan: evaluation of model output sensitivity to input data

ABSTRACT WRF simulations were conducted for Ise Bay, Japan for January and July 2016 to evaluate sensitivity of model input and output above sea surface to the replacement of three default input datasets with region-specific input datasets. For atmospheric input data, a final analysis created by the National Centers for Environmental Prediction (NCEP-FNL) was replaced with a mesoscale analysis created by the Japan Meteorological Agency (JMA). Topography and land use dataset released by the US Geological Survey were replaced with dataset released by the GeoSpatial Information authority of Japan. For sea surface temperature (SST) data, NCEP-FNL was replaced with an analysis created by JMA. Of the three region-specific datasets, replacement of atmospheric data results in the largest improvements in the accuracy of simulated wind speeds in January and July and of temperature in July 2016. Improvements in model output accuracy over sea surface can be seen near the coastline by replacing topography and land use data. Replacement of SST data results in the largest improvements in simulated temperature accuracy in January 2016. Replacing all three default input datasets results in the largest improvement, and expands on results from previous studies that focused on the effects of replacing only one input data.

Carotenoids of land-locked and sea-run types of masu salmon Oncorhynchus masou ishikawae inhabiting in the Nagara River, Japan, from the perspective of chemical ecological study

Carotenoids of the land-locked type (Amago) and sea-run type (Satsukimasu) of masu salmon Oncorhynchus masou ishikawae inhabiting the Nagara River, Gifu Prefecture, Japan were investigated from the perspective of the chemical ecological point of view. Yellow xanthophylls, 3′-epilutein, lutein, zeaxanthin, and diatoxanthin were major carotenoids in wild Amago. They were also present in the flesh of wild Amago. These carotenoids originated from aquatic insects, which wild Amago fed on. On the other hand, tunaxanthin, zeaxanthin, and salmoxanthin were major carotenoids in the integument of Satsukimasu, which migrated from the Ise Bay to the Nagara River. Astaxanthin was a major carotenoid in the flesh of Satsukimasu. These carotenoids accumulated from marine fish and crustaceans, which Satsukimasu fed on during migration in the sea. Carotenoids of Amago and Satukimasu well-reflect their ecological life history.

Investigation of Biofilms Formed on Steelmaking Slags in Marine Environments for Water Depuration.

Steelmaking slags are a promising resource as artificial seaweed beds for the reconstitution of marine environments. To grow seaweed well, the formation of biofilms is an essential process in biofouling. This study focused on the formation of initial biofilms on steelmaking slag samples and analyzed the resulting bacterial communities using the next-generation sequencing technique. Three types of steelmaking slag were submerged in an area of Ise Bay in Mie Prefecture, Japan, for 3 and 7 days in the summer and winter seasons to allow the formation of biofilms. The bacterial communities of these biofilms were richer in sulfur-oxidizing bacteria compared to the biofilms formed on polyurethane sponges. It was found that Helicobacteraceae dominantly grew on the biofilms formed on the slag samples. This shows that steelmaking slags have potential to be used as artificial seaweed beds and marine water purifiers.

Age and Growth of the Horse Clam Tresus keenae in Seto Inland Sea and Ise Bay, Western Japan

The age and growth of horse clams Tresus keenae from Seto Inland Sea (SIS) and Ise Bay, western Japan, were investigated using a water-based marking pen on the edge of sectioned shells, after which unstained translucent zones at the chondrophore could be clearly observed. The translucent zone was formed once per year during autumn. The ages of all the samples were determined. The most frequent shell length (SL) in SIS and Ise Bay populations were 100–120 mm and 120–140 mm, respectively and mainly consisted of 3-y-old and 4-y-old clams, respectively. Clams in the SIS were found to be younger by about 1 y and 20 mm smaller on average than the Ise Bay population. The age–SL relationships of clams from each area were analyzed, using the original von Bertalanffy growth function (VBGF), a VBGF with a biological intercept, and the Gompertz growth function. The original VBGF showed the best fit with the SIS dataset, whereas the Gompertz growth model showed the best fit with Ise Bay clams. The parameters for each growth model were significantly different between SIS and Ise Bay, which may be due to clams younger than 2 y and smaller than 80 mm SL that were present only in the samples from SIS. Faster growth rate of the VBGF in Ise Bay than that in SIS would be affected by higher water temperature during the season of rapid growth.

Estimation of fault models for short-term slow\xa0slip events from groundwater pressure in soft sedimentary layers

Deep low-frequency tremors and short-term slow slip events (SSEs) are known to occur along the Nankai Trough in Japan. Although short-term SSEs are thought to occur repeatedly in the northern part of Ise Bay, deep low-frequency tremors are not observed there. Because the area around the northern part of Ise Bay is characterized by soft sedimentary layers not suitable for strainmeter or tiltmeter installation, there are no high-quality crustal deformation observation sites in the area. Accordingly, the local extent of slip of short-term SSEs has not been confirmed. We significantly improved the crustal strain sensitivity of the groundwater level (pressure) in the inner pipe of the observation well at the Hokusei observation site (HKSi, northwest of Ise Bay) by sealing it with a packer. Consequently, we were able to observe groundwater pressure changes related to slow slip at the plate boundary. We estimate that slip of short-term SSEs during July 2016, November 2017, and April 2018 extended to the northern part of Ise Bay. Furthermore, groundwater pressure fluctuations at HKSi in April 2018 greatly improved the SSE fault model, confirming that slow slip occurs in the area, despite the absence of deep low-frequency tremor. The slips without tremors are a characteristic of the northern area of Ise Bay, differing from other areas of the Nankai Trough. Our results demonstrate that groundwater level/pressure fluctuations are a powerful tool for crustal deformation observations in areas characterized by soft sedimentary layers.

Developing a hydro-chemical model of Ise Bay watersheds and the evaluation of climate change impacts on discharge and nitrate-nitrogen loads

The objective of this study was to develop a hydro-chemical model using the Soil and Water Assessment Tool (SWAT) and to evaluate the climate change impacts on discharge and nitrate-nitrogen loads from Ise Bay watersheds (the Kiso, Nagara, Ibi, and Shonai rivers). Using a regional climate model, through the dynamic downscaling approach, present and future climate data were generated at a 2 km spatial resolution. The pseudo-global warming downscaling approach under the A1B scenario was adopted for future climate prediction. Then, the optimized SWAT model, driven by the present and future climate data, was executed. The following results were obtained: (1) the significant increase of precipitation in May and June and decrease in August in the future climate scenario, and consequent discharge from the target watersheds also increased in May and June and decreased in August and September; (2) Due to the change in discharge, nitrate-nitrogen loads of the Kiso, Nagara, and Ibi rivers also increased in May and June and decreased in August and September; and (3) While nitrate-nitrogen load from deciduous forest tends to decrease, the one from evergreen forest tends to increase. The response of the model indicated the possibility of an increase in nitrogen uptake by deciduous forests.

Genome-wide population structure and genetic diversity of Japanese whiting (Sillago japonica) inferred from genotyping-by-sequencing (GBS): Implications for fisheries management

Japanese whiting (Sillago japonica) is a relatively common marine fish inhabiting in the coastal shallow waters and the target species in an important commercial and recreational fishery. In this study, eighty-three specimens in five sites were collected along coasts of China and Japan, and genotyping-by-sequencing (GBS) technology was carried out to investigate the genetic structure and difference among them. Consistent with prior research conclusions, a relatively high genetic diversity was detected in S. japonica, and an increasing tendency of genetic variation level was detected as the latitude decreased in Chinese populations. Although estimated value of pairwise population differentiation (FST) was low, the genetic heterogeneity analysis demonstrated a certain amount of genetic differentiation among local populations of S. japonica. Samples from Rushan were differentiated from other Chinese populations, but closely correlate with Ise Bay (IB) and Tokoy Bay (TB) populations, indicating gene flow between Rushan population (RS) and Japanese populations to a certain extent. Isolation by distance (IBD) analysis showed that genetic differentiation was significantly affected by geographical isolation. While, the results of isolation by environment (IBE) test showed that genetic distance was correlated with seawater salinity, which might be a selective pressure promoting genetic variation in S. japonica. Given the complex pattern of genetic differentiation of Japanese whiting among Chinese and Japanese populations, we suggested treating them as different management units in utilization of offshore fisheries resources.

Examination of factors causing the depletion of Manila clams (Ruditapes philippinarum) on the eastern coast of Ise Bay, central Japan, using a growth model

Examination of factors causing the depletion of Manila clams (<i>Ruditapes philippinarum</i>) on the eastern coast of Ise Bay, central Japan, using a growth model

マイクロサテライト DNA マーカーから見た伊勢湾内のアサリの遺伝的集団構造

マイクロサテライト DNA マーカーから見た伊勢湾内のアサリの遺伝的集団構造

Environmental monitoring using small fishing boats in Ise Bay for fishery management

It is important to understand and predict fish behavior to assess the impacts of coastal development on ecosystems and to conduct appropriate fishery management. Fish dynamics models have been developed to consider the migration, growth, and population change for conger eel, etc. These models calculate fish behavior based on environmental factors (e.g., water temperature and dissolved oxygen). Meanwhile, since the responses to environmental factors are mainly determined by qualitative information or laboratory experiments, a more detailed investigation is required on the fish behavior in the actual sea. In the present study, in order to collect information for behavioral modeling of fish, we measured the environmental factors and the distribution of fish simultaneously by using fishing boats. The sensors were attached to the fishing gear of the small trawling boats in Ise Bay, Japan, through which the water temperature, and dissolved oxygen were measured along with positional information by using a global positioning system. At the same time, the fish catch of each haul by trawling was recorded, to grasp the fish distribution. The obtained data provided more information for temporal and spatial distribution of water qualities than conventional monitoring. The relationship between the fish density, indicated by Catch Per Unit Effort (CPUE), and environmental factors also were analyzed. The CPUE of the conger eel increased at water temperatures of 18–20 °C and dissolved oxygen values around 2 mg L−1. These results explained the location of fishing grounds based on the fishermen's experiences that the conger eel tends to gather in marginal areas of hypoxia in the summer. These results will be useful to determine the parameters for the fish behavior model.

The identify of Cancer (Arges) parallelus De Haan, 1833 (Decapoda: Brachyura: Pilumnidae), a fossil crab described from Japan during the 19th century

Abstract The revised diagnosis and description are given for Cancer (Arges) parallelusDe Haan, 1833, a fossil crab first described from Japan during the 19th century. The neotype of this species from the Holocene (about 9,000–5,000 ybp) Nanyo Formation of Ise Bay, central Japan, is herein designated. The monotypic genus ArgesDe Haan, 1833 belongs to the pilumnid subfamily Rhizopinae Stimpson, 1858 and has close affinities with TyphlocarcinusStimpson, 1858, a genus of Rhizopinae.

Simulation-Based Exceedance Probability Curves to Assess the Economic Impact of Storm Surge Inundations due to Climate Change: A Case Study in Ise Bay, Japan

Understanding storm surge inundation risk is essential for developing countermeasures and adaptation strategies for tackling climate change. Consistent assessment of storm surge inundation risk that links probability of hazard occurrence to distribution of economic consequence are scarce due to the lack of historical data and uncertainty of climate change, especially at local scales. This paper proposes a simulation-based method to construct exceedance probability (EP) curves for representing storm surge risk and identifying the economic impact of climate change in the coastal areas of Ise Bay, Japan. The region-specific exceedance probability curves show that risk could be different among different districts. The industry-specific exceedance probability curves show that manufacturing, transport and postal activities, electricity, gas, heat supply and water, and wholesale and retail trade are the most affected sectors in terms of property damage. Services also need to be of concern in terms of business interruption loss. Exceedance probability curves provide complete risk information and our simulation-based approach can contribute to a better understanding of storm surge risk, improve the quantitative assessment of the climate change-driven impacts on coastal areas, and identify vulnerable regions and industrial sectors in detail.

Genetic population structure of the eight-barbel loach Lefua echigonia in the Ise Bay region, a single paleo-river basin in central Honshu, Japan

We examined the genetic population structure of Lefua echigonia in the Ise Bay region based on the nucleotide sequences of the mitochondrial DNA cytochrome b region. Previous phylogeographic studies reported that only the Tokai lineage is distributed in this region; however, the present study revealed that the native Kinki lineage (Kuwana sub-lineage) is also distributed here. Moreover, the Tokai lineage was separated into three sub-lineages—Ise Bay, Mikawa-Shizuoka, and Nakatsugawa—with the Ise Bay and Mikawa-Shizuoka sub-lineages further subdivided into six and two local lineages, respectively. We revealed that L. echigonia has clear geographic differentiation within a single paleo-river basin.

Ⅱ-3. Ise Bay and Mikawa Bay

Ⅱ-3. Ise Bay and Mikawa Bay

Relation between Miniaturization of Phytoplankton And Long-Term Variation of Water Quality in Ise Bay

Relation between Miniaturization of Phytoplankton And Long-Term Variation of Water Quality in Ise Bay

Study of the Relation between Water Exchange and Short-Term Variation of Hypoxic Water Mass in Ise Bay with the use of Three-Layered Box Model

Study of the Relation between Water Exchange and Short-Term Variation of Hypoxic Water Mass in Ise Bay with the use of Three-Layered Box Model

Estimation of fish distribution by means of neural network using monitoring data by fishing boats

It is important to understand and predict fish behavior to assess the impacts of coastal development on ecosystem or to conduct appropriate fishery management. In order to collect information for understanding fish behavior, we measured the environmental factors and the distribution of fish simultaneously by using fishing boats. The memory-type sensors were attached to the fishing gear of the small trawling boats in Ise Bay, through which the water temperature, dissolved oxygen, and depth were measured as well as position information by GPS. At the same time, fish catch of each haul by trawling were recorded to grasp the fish distribution. The obtained data provides much more information for temporal and spatial distribution of water qualities than conventional monitoring. We tried to predict resource distributions by artificial neural network using the obtained data. It is found that the environmental factor affecting the behavior of conger eel varies with respect to the months. The developed neural network could predict the horizontal distribution of the conger eel fairly well.

Quantification of Bottom Water Age by Using Temperature Based Age Index Model and Its Relationship with Bottom Water Dissolved Oxygen Concentration in Ise Bay, Japan

Quantification of Bottom Water Age by Using Temperature Based Age Index Model and Its Relationship with Bottom Water Dissolved Oxygen Concentration in Ise Bay, Japan

Distribution of region-specific background Secchi depth in Tokyo Bay and Ise Bay, Japan

Region-specific background Secchi depth (BSD) provides valuable information on light availability in aquatic ecosystems. We estimated BSD in two eutrophic bays located in central Japan, Tokyo Bay and Ise Bay. Estimates were based on monitoring data collected in the period 1981–2015. Reliable BSD estimates were obtained for 89–96% and 67–94% of the monitoring sites in Tokyo Bay and Ise Bay, respectively. Low BSD values were obtained in the innermost sectors of Tokyo Bay (around the Nakagawa, Arakawa and Sumidagawa estuaries) and Ise Bay (around the Shonaigawa, Kisogawa and Ibigawa estuaries). BSD was positively correlated with salinity in both bays, indicating that river-supplied substances, including tripton and/or colored dissolved organic matter, strongly influenced BSD values. Although the highest chlorophyll a concentrations were measured in the innermost sectors of both bays, the proportional contribution of phytoplankton to light attenuation was surprisingly low in comparison with other sectors of the two water bodies. In both bays, phytoplankton accounted for <40% of light attenuation through the water column, indicating that background factors played a dominant role even in these highly eutrophic waters. Determinations of Secchi depth, BSD, and the proportional contributions of phytoplankton and background factors to light attenuation will improve understanding of the aquatic light environment, which in turn will inform the development of rational coastal management practices.

2015A-GS19-1 伊勢湾沿岸の高潮特性を考慮した高潮ハザードマップに基づくコンテナ被害の検討

2015A-GS19-1 伊勢湾沿岸の高潮特性を考慮した高潮ハザードマップに基づくコンテナ被害の検討