East Asian Seas Research Articles

Pile driving noise impacts behavioral patterns of important East Asian juvenile marine fishes

The surge in renewable energy demand, particularly from offshore wind farm (OWF), raises concerns about underwater noise pollution during their construction. Despite extensive studies on underwater noise impacts in European and Western countries, local species targeted investigations are crucial for global application. We assessed how pile driving noise during OWF construction affected the behavior of three juvenile Korean fishes (Lateolabrax japonicus, Acanthopagrus schlegelii, and Platichthys stellatus) prevalent in East Asian seas. Pile driving noise playback induced rapid changes in L. japonicus and A. schlegelii swimming speed and group cohesion, with 40 % remaining un-habituated after 5 min. Notably, L. japonicus showed clear avoidance of the noise source, while P. stellatus behavior remained unchanged at all. Our findings confirm that even relatively low-intensity impulsive noise can alter fish behavior, potentially due to species-specific characteristics. Accumulated data will inform the development of strategies for smart OWF establishment, advancing sustainable energy practices.

Genome-wide SNP analysis coupled with geographic and reproductive-phenological information reveals panmixia in a classical marine species, the Japanese jack mackerel (Trachurus japonicus)

Identification of genetic population structures in classical marine species—species with large population sizes, wide range distributions, and high dispersal potential—can be a challenging task because of expectedly weak genetic signals of population structure. The Japanese jack mackerel, Trachurus japonicus, is a classical marine species and one of the most important fishery resources in the East Asian seas. In this study, we tested the hypothesis of genetic panmixia in the Japanese jack mackerel using genome-wide SNP analyses coupled with geographic and reproductive phenology information. We generated a highly contiguous genome assembly and performed Genotyping by Random Amplicon Sequencing-Direct (GRAS-Di) to produce at least 19,904 SNPs that were genotyped in 614 samples from seas around the Japanese archipelago. Genetic population structure analyses did not reveal any evidence of genetic differentiation. Neither geographical barriers in the Japanese archipelago nor phenological differences in reproductive timing affected the genetic population structure. Overall, these findings were consistent with the interpretation of genetic panmixia, providing evidence for high genetic connectivity across the population’s distribution. Considering the current knowledge about the distribution and life history of T. japonicus, we suggest that the panmictic status may reflect a metapopulation structure with source-sink dynamics and/or extensive gene flow across the distribution range.

Source-resolved atmospheric metal emissions, concentrations, and deposition fluxes into the East Asian seas

Source-resolved atmospheric metal emissions, concentrations, and deposition fluxes into the East Asian seas

Managing institutional interlinkages for the protection of marine environment in the East Asian seas region and beyond: The case of marine plastic pollution

The protection of the marine environment in the East Asian region (EAS region) faces a significant challenge from marine plastic pollution (MPP), highlighting the need for effective regulations and management by regional institutions. Employing empirical research methods, we examine the existing variation of institutional architectures and their regulatory measures regarding MPP in this region. Our study reveals regional institutions and initiatives established to address marine environmental protection against this issue, resulting in a variety of complex and overlapping regulations and policies. While these efforts show positive impacts, gaps in implementing regulations and policies remain significant. Managing institutional interlinkages is crucial to enhancing the effectiveness and accountability of efforts against MPP. In this context, we propose the concept of interplay management as a strategy to improve these efforts in the EAS region. Furthermore, our research highlights the necessity of implementing the concept of polycentric governance in future global agreements on plastic pollution, including marine environments. This approach aims to foster better cooperation and coordination among regions and institutions involved in marine environmental protection against MPP.

Application of multiplatform remote sensing data over East Asia Ocean: aerosol characteristics and aerosol types.

It is important to explore the characteristics and rules of atmospheric aerosol in the East Asian Sea for monitoring and evaluating atmospheric environmental quality. Based on Aerosol Robot Network (AERONET), Visible Infrared Imaging Radiometer (VIIRS), and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data, the temporal and spatial variation characteristics and differences of aerosol parameters and types in the East Asian Sea were studied by using figure classification method (FIGCM), aerosol optical depth (AOD)440-Angstrom exponent (AE)440-870 method (AA1M), and AOD550-AE490-670 method (AA2M). The results show that the seasonal variation trend of aerosol characteristics and types is obvious in East Asia Sea. AOD, volume concentration (Cv), and aerosol effective radius (reff) in the Bohai-Yellow Sea and the Sea of Japan in autumn are lower than those in other seasons, and the occurrence frequency of ocean-type aerosols is high. Different from the Bohai-Yellow Sea and Sea of Japan, human activities in winter, summer, and autumn seriously affect the air quality in the East China Sea and South China Sea. Especially at the Taipei CWB site, from aerosol parameters and high biomass burning/urban industrial (BB/UI) aerosol, human activity is an important factor for high pollution at the Taipei CWB site. Aerosol types of AA1M, FIGCM, AA2M, and CALIPSO were compared at Anmyon and Yonsei University sites in the Bohai-Yellow Sea in March 2020. The results show that aerosol types based on threshold classification methods generally have higher mixed aerosol results, and the marine (MA) results of AA1M, FIGCM, and AA2M are close to the clean marine aerosol results of CALIPSO. Comparing the results of AA 2M and CALIPSO on a spatial scale, it is found that the clean marine aerosol proportion identified by CALIPSO (0.38, 0.48, 0.82) is consistent with the MA proportion identified by AA 2M (0.43, 0.46, 0.97) in the East China Sea, South China Sea, and Western Pacific Ocean.

Late Pleistocene sea level change and tectonism control on the formation of the Old Red Sand along the southeastern coast of China

The Zhe-Min Uplift (ZMU) has undergone tectonic subsidence, which has been associated with a notable transgression in the northern marginal seas of China since the middle Pleistocene. However, its uplift history during the late Quaternary is still inadequate. The Old Red Sand (ORS) is a late Pleistocene deposit that is widely distributed along the southeastern coast of China. The ORS consists of partially-cemented fine- to medium-grained sand. In this paper, we focus on mud-rich ORS deposits of the Liushui area, Pingtan Island, Fujian Province, and report optically stimulated luminescence (OSL) ages, and new datasets of grain size, mineralogy (detrital zircon, clay and detrital minerals) and organic carbon and nitrogen isotope profiles to improve understanding of chronology, provenance, palaeoenvironmental evolution and tectonic infuence. Based on the OSL data, we hypothesize that the development of the ORS was associated with lower sea levels, with most deposition occurring within MIS4. Based on comparison of detrital zircon UPb ages, the coarse fraction of the Liushui ORS was mainly derived from the Minjiang River, with modest input from weathering of coastal granites. The East Asian Winter Monsoon contributed some materials from the East China Sea shelf during the last glacial period, as indicated by the fine-grained nature of the Liushui ORS, low K-feldspar/plagioclase ratios, high dolomite content and the frequency of Neoproterozoic and Palaeoproterozoic detrital zircons. The deposition of the ORS was influenced by both the East Asian Winter Monsoon and sea level changes. The clay minerals in the mud layers of the Liushui ORS were dominated by kaolinite and illite, with little chlorite and no smectite, indicating that they originated from the Minjiang River. The TOC/TN ratios of the mud layers, as well as their isotope characteristics, indicate the organic matter was derived from marine sources, presumably during the transgression event in MIS5. The average uplift rate of the ORS was about 0.03 mm/yr. The uplift of the ORS provided new insights into the geological records of the ZMU, which differed from the subsidence observed in the northern region of the Minjiang River during the late Pleistocene.

Spatiotemporal estimation of nutrient data from the northwest pacific and east asian seas

Nutrient data obtained from field observations have the potential to enhance our understanding of oceanic biogeochemical cycling and productivity changes. In particular, long-term nutrient data can provide valuable information on the links between climate change and biogeochemical changes. However, unlike other observational variables such as sea surface temperature, nutrient data are limited in terms of their broad-scale observations and automated sensor-based measurements. In this study, we analyzed nitrate and phosphate data obtained from coastal regions in Northeast Asia and the northwest Pacific from 1980 to 2019 using the spatiotemporal kriging technique and provide results in a spatiotemporal grid format. The data are available at monthly intervals and may be attractive to researchers in the fields of oceanography, marine ecology, and marine biogeochemistry at the climate change scale. Furthermore, sharing the source code of the data production process can contribute to better long-term data reproduction in the future.

Analysis of Extreme Precipitation Variation Characteristics and the Influencing Factors in the Yunnan-Guizhou Plateau Region, China

The increase of extreme precipitation (EP) frequency and the aggravation of disasters have seriously disrupted the normal economic and social development of human beings. The complex topography of the Yunnan-Guizhou Plateau region (YGPR) and the fact that moisture originates from two different directions, the Pacific Ocean and the Indian Ocean, make the mechanism of EP more complicated. Exploring the variation characteristics and influencing factors of EP in YGPR is of great significance for regional disaster prevention and mitigation and water resources management. In this study, 11 extreme precipitation indices (EPIs) defined by the Expert Team on Climate Change Detection and Indices (ETCCDI) were calculated based on daily precipitation data of 1960–2020 from 83 national meteorological stations in the study area. The Mann–Kendall test and Wavelet analysis were used to analyze the variation characteristics of EP and explore the influence mechanisms of geographical factors and atmospheric circulation on EP in the spatial and temporal perspective. The conclusions are as follows: (1) The EP of the study area has an overall increasing trend in the research period, with the increase of persistent dry days, the precipitation concentration, intensity, and extreme heavy precipitation (EHP); (2) It shows the obvious spatial difference in the study area, with the high-value areas of extreme drought (ED) in the northwestern region and the total annual precipitation, EHP, and intensity in the southeastern region. In addition, ED and EHP tends to increase in the western region of the study area as well as in the middle east and southeast; (3) EHP is significantly positively correlated with longitude and highly negatively with latitude. Meanwhile, EHP shows a correlation with altitude (negative at low altitude and positive at high altitude); (4) The degree of drought change is greatly affected by North Atlantic Oscillation/El Niño-Southern Oscillation (ENSO) events. The variation of extreme heavy precipitation is greatly influenced by the summer monsoon of South Asian, East Asian, and South China Sea; (5) All the EPIs show persistence. The study results can contribute to the understanding of EP variation in the study area and provide some scientific references for regional water resource management, meteorological warning, and agricultural production safeguard.

The Impact of Changes in Sea Level and East Asian Monsoon on Sediment Transport on the Sunda Shelf Since the Last Deglaciation

AbstractThe Sunda Shelf plays a key role in the sedimentation of the southern South China Sea (SCS). However, the impact of past climate changes on sediment transfer to the Sunda Shelf and the southern SCS is still unresolved. Here, we present new data on grain size, clay mineralogy, and Sr‐Nd isotopes of three marine cores, river sediments, and surface sediments of the Sunda Shelf. The results indicate that clay fractions of the central Sunda Shelf and the Gulf of Thailand derived mainly from the Mekong River and the rivers of northern Thailand since the last deglaciation. Significant changes in sediment sources are observed at 7.5 cal ka BP. From 13.3 to 7.5 cal ka BP, sediments in the Gulf of Thailand mainly originated from the rivers of northern Thailand, with contributions from the Mekong River increasing after 7.5 cal ka BP. An opposite shift is observed in the central Sunda Shelf. Such variations in the spatial distribution result from a combination of sea level and East Asian monsoon effects. After 7.5 cal ka BP, less Mekong River sediments were transported southeastwards into the southern SCS, and more sediments were gradually trapped within the delta and transported in a southwesterly direction into the Gulf of Thailand due to intense East Asian winter monsoon, which forced a strong southwestward coastal current. Our results demonstrate the important impact of East Asian winter monsoon strengthening and sea level rise in the mid‐Holocene, which can change sediment sources and transport processes on the Sunda Shelf.

Spatial estimation and yearly trends in abundance-index of Japanese jack mackerel (Trachurus japonicus) in the East China Sea and Sea of Japan

Catch per unit effort (CPUE) of commercial fisheries is recommended to be standardized because various factors can affect catch rates. Recently, the spatio-temporal analysis has been required to standardize fishery data, because catch is spatially distributed in proportion to fishery distribution and not in proportion to fish abundance. We developed the spatio-temporal models for the CPUE of large- and medium-sized purse seine fisheries for the different age groups of Japanese jack mackerel (Trachurus japonicus) to evaluate the potential spatial distribution and estimate the annual trends in abundance index. Japanese jack mackerel is widely distributed in the East Asian seas, including the East China Sea and Sea of Japan, and is an important fishery resource in Japan. Our models were delta-lognormal generalized additive mixed models that incorporated the temporal components of year and month, and size of fishing vessels as categorical variables, and the identity of the fishing vessels as a random variable. The spatial component represented by the latitude and longitude points of the fishing location was smoothed using an isotropic bivariate function. The water temperature at a depth of 50 m was incorporated to detect the effects of environmental factors. After all combinations of explanatory variables were evaluated, the model with the lowest Bayesian information criterion score was selected as the best model. All the best models among both binomial models and lognormal models contained all explanatory variables, although the best binomial model for age 2 exclude the vessel size and the best lognormal model for age 0 exclude the water temperature at a depth of 50 m. Our results indicate that the potential distribution areas for all ages of Japanese jack mackerel exist on the continental shelf in the southern part of the East China Sea, the western side of Kyushu Island, and along Honshu Island in the western part of the Sea of Japan. In contrast, the main distribution areas with higher density for age 0 were segregated into two: the southwestern East China Sea and the coastal area off Kyushu Island, although fish over age 1 were widely distributed. The standardized CPUE was higher than the nominal CPUE for age 0 from 2015 to 2020, and the standardized CPUE was also higher for age 1 in 2020. These results were derived from spatial models that compensated for the lack of spatial data due to the recent decrease in fishing operations in the Southeast China Sea. The yearly trends of standardized CPUE for each age could be used for the age-structured stock assessment model such as a tuned virtual population analysis. Improving the accuracy of the abundance index helps to further improve the reliability of stock assessments.

Decadal stability in coral cover could mask hidden changes on reefs in the East Asian Seas

Coral reefs in the Central Indo-Pacific region comprise some of the most diverse and yet threatened marine habitats. While reef monitoring has grown throughout the region in recent years, studies of coral reef benthic cover remain limited in spatial and temporal scales. Here, we analysed 24,365 reef surveys performed over 37 years at 1972 sites throughout East Asia by the Global Coral Reef Monitoring Network using Bayesian approaches. Our results show that overall coral cover at surveyed reefs has not declined as suggested in previous studies and compared to reef regions like the Caribbean. Concurrently, macroalgal cover has not increased, with no indications of phase shifts from coral to macroalgal dominance on reefs. Yet, models incorporating socio-economic and environmental variables reveal negative associations of coral cover with coastal urbanisation and sea surface temperature. The diversity of reef assemblages may have mitigated cover declines thus far, but climate change could threaten reef resilience. We recommend prioritisation of regionally coordinated, locally collaborative long-term studies for better contextualisation of monitoring data and analyses, which are essential for achieving reef conservation goals.

Cultural Exchange in the East Asian Seas in Light of the Acceptance of Mazu Beliefs by Japanese Sea Gods

This paper examines the local beliefs of the sea gods in Japan, represented by the Sumiyoshi Sanjin 住吉三神, and their acceptance of the foreign culture of Mazu 媽祖. While there are many differences between the two in terms of their backgrounds, functions, and identities, the evolution of Japanese sea god beliefs has been characterized by a gradual acceptance of Mazu culture, culminating in the co-culturing of the two in shrines. This paper adopts an empirical research design to compare the local beliefs of the sea gods in Japan with the culture of Mazu and to analyze the reasons for their acceptance of Mazu culture from the perspective of the other. This article argues that the Japanese sea gods accepted Mazu for two reasons: the tangibility of Mazu’s beliefs and the superb spirituality of Mazu’s beliefs. Superb spirituality means effective protection, both in terms of safety at sea and swiftness in rescuing shipwrecks, and in terms of the smooth running of the fishing industry.

동아시아의 관점으로 본 백제 한성기 해양 네트워크

Paekche''s maritime history research had emphasized maritime activities from a nationalistic perspective, but it is necessary to examine the status of Paekche history, which was connected to both China and Japan through the East Asian sea. This connection in East Asia can be accessed through the concept of ‘network’. The concept of ‘network’ in this study is divided into two. The first is the concept of a ‘coastal route network’, the second is a pluralistic “ocean network”. The marine network during the Hansŏng period of Paekche is divided into the first - 3rd centuries, the second - 4th centuries, and the third - 5th centuries. In the first period, the coastal route network was maintained led by China, and in the second period, after the coastal route network was strained, Paekche connected to China with a new route, and rebuilt the south-west coastal route network. The third period was a period when Paekche tried to maintain its network of coastal routes, although the stability of the Yellow Sea central cross route was reduced due to Koguryŏ. Paekche was the important node of the East Asian maritime network. However, Paekche during the Hansŏng period did not dominate all coastal areas, and it was operated in the form of a network while maintaining the independence of coastal maritime forces. The East Asian maritime network, which Paekche connected through cross route and coastal routes, was a multidisciplinary order.

Using relative return‐on‐effort scoring to evaluate a novel coral nursery in Malaysia

Coral reefs in Malaysia have been degraded by environmental and anthropogenic stressors, and enthusiasm for coral propagation aimed at site restoration is rapidly growing as a local management tool. However, coral propagation activities in the region are in their infancy and little data currently exists to guide and inform effective practices. We therefore established the first multi‐taxa coral tree nursery (6 species and 300 fragments) in Malaysia and tracked survival and growth to determine the relative return‐on‐effort (RRE) over an approximately 14‐month monitoring period. We observed differences in growth and survival among six coral species and were successful at benchmarking results against coral restoration operations globally and in the East Asian Seas region. Major findings include (1) overall ranges in species level survivorship of 34–94% and specific growth rate of 0.14–0.29%/day, leading to variable RRE scores among species, (2) variable growth rates among coral species based on seasonal changes in environmental conditions, (3) similar RRE scores to other nursery locations worldwide, which suggests effective practice, and (4) calculation of RRE scores for species not previously reported in nursery culture (Acropora florida, A. hoeksemai, and Echinopora horrida). Ultimately, our study supports previous findings that RRE is an effective technique for comparing coral nursery performance and offers valuable insight to guide future restoration activities in Malaysia.

History of coastal dune evolution in the Fujian region of southeastern China over the last millenium

Coastal dunes are a product of the evolution of the coastal environment. Previous research shows that dune development in the Fujian coastal region correlates well with the fluctuations of East Asian winter monsoon (EAWM) and sea level. However, comparison of coastal dune evolution along the Fujian coast since 1 ka with various paleoenvironmental indicators shows that, in addition to EAWM and sea level change, increased frequency and intensity of typhoon landfalls and tropical cyclone may have played an important role in dune building. Here we present the results of optically stimulated luminescence (OSL) dating and analyses of lithostratigraphy, grain size, and color of late Holocene aeolian sediments from Shenhu Bay of the Fujian coast, Southeastern China. Together with published chronological data from the region, three phases of coastal aeolian activity are defined: ~1050–1300 CE (the Medieval Climatic Anomaly, MCA), ~1450–1700 CE (early Little Ice Age, LIA), and ~ 1750–1930 CE (late LIA). These phases of sand accumulation had different sand sources: the source for the two phases of ~1050–1300 CE and ~ 1450–1700 CE was the reworking of the adjacent “old red sand”, and that for the phase of ~1750–1930 CE was beach and/or foredune sand. During ~1050–1300 CE, although the sea level was relatively high and the beach sand source was relatively limited, the increased frequency of typhoon landfalls and the widely distributed “old red sand” deposits provided important dynamic and provenance conditions for the formation of coastal dunes. During ~1450–1700 CE, strong EAWM and increased frequency of typhoon landfalls were all conducive to aeolian activities. On the contrary, the strong aeolian activity during ~1750–1930 CE may be related to sea level drop and strong EAWM.

Multifeature superposition analysis of the effects of microplastics on microbial communities in realistic environments.

Microplastic (MP) contamination has become an increasingly serious environmental problem. However, the risks of MP contamination in complex global climatic and geographic scenarios remain unclear. We established a multifeature superposition analysis boosting (MFAB) machine learning (ML) approach to address the above knowledge gap. MFAB-ML identified and predicted the importance, interaction networks and superposition effects of multiple features, including 34 characteristic variables (e.g., MP contamination and climatic and geographic variables), from 1354 samples distributed globally. MFAB-ML analysis achieved realistic and significant results, in some cases even opposite to those obtained using a single or a few features, revealing the importance of considering complicated scenarios. We found that the microbial diversity in East Asian seas will continually decrease due to the superposition effects of MPs with ocean warming; for example, the Chao1 index will decrease by 10.32% by 2065. The present work provides a powerful approach to identify and predict the multifeature superposition effects of pollutants on realistic environments in complicated climatic and geographic scenarios, overcoming the bias from general studies.

Systematical insights into distribution and characteristics of microplastics in near-surface waters from the East Asian Seas to the Arctic Central Basin

The spatial distribution and composition of microplastics in near-surface water (8 m) was investigated from the East Asian Seas to the Arctic Central Basin. Microplastics were detected in 93.9% of the sampling sites. Abundances ranged from 0.48 to 7.62 items/m3, with an average abundance of 2.91 ± 1.93 items/m3. The highest average abundance was observed in the Arctic Central Basin. Polyester (PET) was the dominant type, accounting for 71.3% of total microplastics, followed by rayon or cellophane and polytetrafluoroethylene (PTFE). Microplastics < 2 mm accounted for 81.9% of total particles. Its distribution peaked in the 1–2 mm size range. The 0.30–2 mm fibers were the most abundant. In the East Asian Seas, the abundance was significantly negatively correlated with longitude, whereas the accumulation of microplastics was not observed in the northeastern sector of Japan Sea. Abundances of microplastics at sites located in the sub-Arctic and Arctic Oceans showed a significant positive relationship with latitude, indicating that the Arctic Ocean is a potential accumulation zone of microplastics. The findings of this study will provide systematical insights into distribution of microplastics and basic information for understanding the accumulation mechanism of microplastics in near-surface waters from the East Asian Seas to the Arctic Central Basin.

Projection of future sea level rise in the East Asian Seas based on Global Ocean-Sea Ice Coupled Model with SRES A1B Scenario

To project the future sea level rise in the East Asian Seas due to global warming, regional sea level variations are downscaled from three climate system models (GFDL-CM2.1, ECHAM5/MPI-OM, MIROC3.2(hires)) using a global ocean-sea ice coupled model with non-Boussinesq approximation. Based on the SRES A1B Scenario, the projected ensemble mean sea level rise (rate of rise) for the East Sea, Yellow Sea and East China Sea from 1995 to 2050 is 15.60cm (2.84mm/year), 16.49cm (3.0mm/year) and 16.43cm (2.99mm/year), respectively. With the inclusion of the future change of land ice melting and land water storage, the mean sea level rise (rate of rise) increases to 33.55cm (6.10mm/year) for the East Sea, and 34.38~34.44cm (6.25~6.26mm/year) for the Yellow and East China Seas. The present non-Boussinesq ocean model experiment shows that the future sea level rise in the East Sea is mainly due to the steric component changes by heat content increase. On the other hand, the future sea level rise in the Yellow and East China Seas appears to be mainly associated with the non-steric component change by water mass convergence.

Development of High-Resolution Regional Climatology in the East/Japan Sea With a Primary Focus on Meridional Temperature Gradient Correction

In this study, we developed a new high-resolution regional climatology (0.1° by 0.1° by 19 levels) in the East/Japan Sea. National Centers for Environmental Information and Korea Oceanic Data Center already released the regional climatology of East Asian seas including the East/Japan Sea with 0.1° by 0.1° resolution. It provides a reliable temperature and salinity structure compared to previous 1° or 0.25° climatologies. However, this study found an abnormal meridional temperature gradient problem when calculating geostrophic currents based on this new climatology. Geostrophic currents show a strong repetitive eastward flow along the 1° latitudinal band especially in the East/Japan Sea, which corresponds with abnormal meridional temperature gradients at the same areas. This problem could be related to the objective analysis procedure generating the high-resolution climatology. Here, we reproduced a high-resolution climatology without the abnormal meridional temperature gradient problem by using the optimal interpolation method. Results show that the meridional gradient problem can partly be attributed to both the use of the World Ocean Atlas background field on the 1° grid, and the spatial distribution of World Ocean database observation data; however, these are not the primary causes. We corrected the abnormal temperature gradient by increasing the meridional decorrelation length scale without losing the meso-scale feature in the East/Japan Sea, as shown by the wavelet analysis. Improvement of the new gridded field is also validated by using serial hydrographic data and the altimetry-derived surface current product.

1920년대 開城商人의 동아시아 해역 견문기

일본의 근대적인 해운업의 발전과 함께 동아시아 해역에는 증기선 정기항로가 출현하였고, 외국으로의 출국도 용이해져 해외로 나가는 사람들이 비약적으로 증가하였다. 일본총독부와 미쓰이물산(三井物産)의 초청을 받아 1923년 일본과 중국, 1928년 대만과 홍콩 등지의 홍삼수출시장을 시찰하게 된 개성상인 孔聖學과 孫鳳祥은 일본국적의 증기선을 이용하여 동아시아 해역에 건설된 해항도시들을 견문하고 『中遊日記』와 『香臺紀覽』을 남겼다.<BR> 먼저 제2장에서는 1923년 개성상인 공성학이 상해와 중국북부를 여행하고 남긴 『中遊日記』속의 증기선과 해항도시에 관련된 일기와 시를 중심으로 살펴보았다. 공성학과 개성상인들은 사람과 물자의 이동이 증대하고, 시간적 거리가 줄어들고 있는 동아시아 해역을 경험했고, 양자강과 부속 하천을 여행하면서 열강의 해운회사들에 의해 내륙 깊숙이까지 확장된 동아시아 해역을 인식하게 되었으며, 황해를 넘어 발해까지 확장된 일본과 열강의 세력을 확인하게 되었다. 또한 해항도시 상해를 방문한 개성상인들은 개항 이후 상해가 이룩한 경제적, 물질적 번영이 일본의 동경을 넘어서는 것임을 목격하였을 뿐만 아니라, 이 도시의 실질적인 지배자가 서구 열강임을 확인하였다. 또한 해항도 시 상해의 소비문화와 향락문화를 경험하였다. 그리고 해항도시 청도와 지부, 대련을 통해 동아시아 해역에서 벌어지는 일본과 미국을 포함한 서구열강의 경쟁을 확인하게 되었다.<BR> 제3장에서는 1928년 개성상인들이 선상에서 경험한 서양의 기계문명과 생활문화, 그리고 홍콩과 하문 등 해항도시에서 느낀 소회를 살펴보았다. 개성상인들은 선상에서의 예절과 서구인들의 일상문화에 대해 관심을 가지게 되었고, 증기선의 구조와 항해법에 대해서도 견문하였으며, 선상규칙을 준수하고 예의범절을 잃지 않는 서양인과 직접 접촉하게 되면서 서양인들을 야만적인 침략자라 여겼던 인식에도 변화를 가져왔다. 개성상인들은 해항도시 하문의 아름다운 섬 고랑서의 아름다움에 매료되었고, 개항이후 급속한 성장을 이룩한 해항도시 홍콩의 발전에 경탄하였다. 개성전기회사라는 민족회사를 운영하던 개성상인들은 특히 홍콩의 야경에 대해 끊임없는 찬사를 보내며, 어떻게 하면 이런 번영을 이룰 수 있을까에 대해 고민하게 되었다. 일본의 증기선을 이용하여 동아시아 해역을 여행한 개성상인 공성학은 새로운 시대의 조류를 파악하고 낡고 좁았던 자신의 세계를 깨고 근대적인 인물로 거듭날 수 있기를 희망하게 되었다.