• Korean Journal of Ichthyology
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• v.32 no.1
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• pp.14-20
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• 2020

The purpose of this study is to clarify when spawning occurs of Clupea pallasii in the coastal waters of Jinhae Bay and Yeongun-ri, Tongyeong, Korea from December to February using SCUBA observation which is known as spawning season. Eighteen surveys of SCUBA diving observations have performed at 3 stations of Jinhae Bay from December 2017 to January 2018 and 24 times of survey at Yeongun-ri, Tongyeong from December 2017 to February 2018. In Jinhae Bay, average 740,274 eggs/㎡ fertilized eggs were observed in Judo Island and average 671,718 eggs/㎡ were observed in Gusan-myeon. On December 30, 2017, about 388,444 eggs/㎡ fertilized eggs were observed in Yeongun-ri, Tongyeong but no eggs were founded in next surveys. The results in this study suggest that spawning season of C. pallasii in the coastal waters of Jinhae Bay and Tongyeong begins in late December at average 7.7℃ water temperature.

• 한국해양학회지
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• v.9 no.2
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• pp.19-30
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• 1974

Current observations were carried out in Jinhae Bay area during the period of January to February 1974. The data were synthetically analyzed and the characteristics of the water movement in Jinhae Bay were studied. The water movement in Jinhae Bay area is a reversing tidal current type and the Semi- diurnal tidal current is predominant. The ebb current begins at about high water time and the strongest current occurs at about 3 hour after high water. The flood current begins at 0.2-1.0 hour before low water and the strongest current occurs at about 3-4 hour after low water. The main ebb current flows to SE direction with the maximum welocity, about 100cm/sec and the lood flows to NW with the maximum velocity, about 70cm/sec. Generally, the ebb current in Jinhae Bay is more predominat than the flood current except at the west and the north coast area of Gadeog-do where the flood current is more predominant.

• Ocean and Polar Research
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• v.33 no.3
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• pp.291-301
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• 2011

To investigate major factors controlling variations in water quality, principal component analysis and cluster analysis were used to analyze data sets of 12 parameters measured at 23 sampling stations of Jinhae Bay during winter and spring. Principal component analysis extracted three major factors controlling variations of water quality during winter and spring. In winter, major factors included freshwater input, polluted material input, and biological activity. Whereas in spring they were polluted material input, freshwater input, and suspended material input. The most distinct difference in the controlling factors between winter and spring was that the freshwater input was more important than the polluted material input in winter, but the polluted material input was more important than the freshwater input in spring. Cluster analysis grouped 23 sampling stations into four clusters in winter and five clusters in spring respectively. In winter, the four clusters were A (station 5), B (stations 1, 2), C (station 4), and D (the remaining stations). In spring, the five clusters included A (station 5), B (station 1), C (station 3), D (station 6), and E (the remaining stations). Intensive management of the water quality of Masan and Hangam bays could improve the water quality of Jinhae Bay since the polluted materials were mainly introduced into Jinhae Bay through Masan and Hangam bays.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1369-1382
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• 2007

To find proper water quality management strategy for oxygen consumption organic matters in Jinhae bay, the physical process and net supply/decomposition in terms of COD was estimated by three-dimensional eco-hydrodynamic modeling. The estimation results of physical process in terms of COD showed that transportation of COD was dominant in loading area from land to sea, while accumulation of COD was dominant in $middle{\sim}bottom$ level. In case of surface level, the net supply rate of COD was $0{\sim}60\;mg/m^2/day$. The net decomposition rate of COD was $0{\sim}-0.05\;mg/m^2/day$($-5{\sim}-10$ m, in depth) to 2 level, and $-0.05{\sim}-0.20\;mg/m^2/day(10m{\sim})$ to bottom level. These results indicate that the biological decomposition and physical accumulation of COD are occurred for the most part of Jinhae Bay bottom. The variation of net supply or net decomposition rate of COD as reducing land based input loading is also remarkable. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters to improve the water quality of Jinhae Bay.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.43-56
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• 2004

The seasonal distribution pattern of zooplankton were studied on the basis of the zooplankton samples collected from 9 stations in Jinhae Bay in May, August, November and February, 2001 to 2002. A total of 31 species in 37 taxa was occurred in Jinhae Bay. Copepods were pyedominant through fall to spring and cladecerans in summer. There aye high spatio-temporal fluctuations in the zooplankton abundance in a range of 27 to 28,221 indiv. $m^{-3}$. Of these, an neritic species, Acartia omorri and Oentropages abdominals were predominent in february; Palaealanus parvus s. 1 in November; Penilia avirostris in August. Species diversity was low in the northwestern regims where anoxia layer is occurred in summer, while in the other seasons there was no a great difference between stations. It indicates that the distribution pattern of zooplankton may be seasonally strongly affected by a mechanism of hypoxia formation in Jinhae Bay.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.125-132
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• 2010

In order to assess the effect of pollution on marine ecosystem, we examined the plankton health assessment at 16 stations during summer season in Jinhae Bay. The organic and inorganic pollutant sources (dissolved organic carbon; DOC, chemical oxygen demand; COD and Chlorophyll a; Chl.a), including planktonic orangism such as enterobacteria Escherichia coli, heterotrophic bacteria (HB), autotrophic nano-flagellates (ANF), heterotrophic nano flagellates (HNF), ciliate and harmful algal bloom species (HABs) were used to characterize marine ecosystem health assessment. Of these, we tentatively selected those items Chl.a, HABs, HB and E. coli for plankton health index (PHI). Also, the scoring criteria for each metric were based on a statistical analysis and then, the grades are rated on four levels. As a result, the ecological assessment of these data reveals that PHI in Jinhae Bay is rated as "Good or fair" for overall conditions. The present study suggests that the PHI might be considered as one of important management tool to assess marine ecosystem health of Jinhae Bay.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.137-142
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• 2013

To understand critical aspects of paralytic shellfish poisoning (PSP) in a chief area of bivalve production in Korea, seasonal variation in PSP toxins in bivalves collected from Jinhae Bay, Korea in 2009 was surveyed by the pre-column high-performance liquid chromatography oxidation method. We also confirmed the profiles of major bivalves such as oysters Crassostrea gigas and mussels Mytilus galloprovincialis in Jinhae Bay. PSP toxins in the bivalves showed remarkable seasonal variation. PSP toxin levels were detected from April to May in 2009, and the highest total toxin levels at all stations were recorded in May. The major toxins in bivalves were gonyautoxin [GTX] 1&4 and C 1&2; in oysters GTX 2&3 were also detected as major components. GTX 1&4, which showed the highest PSP toxin levels at each station, accounted for the highest proportions of toxin components in mussels and oysters (64.5-71.3% and 41.4-42.4%, respectively). It was also confirmed that the highest toxicity (in ${\mu}g$ saxitoxin [STX] eq/g) was derived from GTX 1&4. The highest total toxicity (in ${\mu}g$ STX eq/g) was approximately 2-8-fold higher in mussels than in oysters collected from the same station. PSP toxin levels in bivalves differed significantly according to the sample collection station. However, the profiles of toxins in the bivalves did not show significant differences during the survey period according to sample collection station. This study shows that PSP toxin levels in some samples from Jinhae Bay were above the regulatory limit in Korea during a specific period in spring.

• ALGAE
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• v.38 no.4
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• pp.265-281
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• 2023

Hypoxia can indeed impact the survival of protists, which play a crucial role in marine ecosystems. To better understand the protistan community structure and species that can thrive in hypoxic waters, we collected samples from both the surface and bottom waters during the hypoxic period in Jinhae and Masan Bays and the non-hypoxic period in Jinhae Bay. Subsequently, we utilized metabarcoding techniques to identify the protistan species. During hypoxia, with dissolved oxygen concentrations of 0.8 mg L^-1 in Jinhae Bay and 1.8 mg L^-1 in Masan Bay within the bottom waters, the phylum Dinoflagellata exhibited the highest amplicon sequence variants richness among the identified protist phyla. Following the Dinoflagellata, Ochrophyta and Ciliophora also displayed notable presence. In hypoxic waters of Jinhae and Masan Bays, we identified a total of 36 dinoflagellate species that exhibited various trophic modes. These included one autotrophic species, 14 mixotrophic species, 9 phototrophic species with undetermined trophic modes (either autotrophic or mixotrophic), 2 kleptoplastidic species, and 10 heterotrophic species. Furthermore, the hypoxic bottom water exhibited a greater number of heterotrophic dinoflagellate species compared to the non-hypoxic surface water within the same water column or the non-hypoxic bottom water. Therefore, feeding by mixotrophic and heterotrophic dinoflagellates may be partially responsible for their dominance in terms of the number of species surviving in hypoxic waters. This study not only introduces the initial documentation of 26 dinoflagellate species surviving in hypoxic conditions but also establishes a foundation for a more comprehensive understanding of the ecophysiology of dinoflagellates in hypoxic marine environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.397-409
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• 2024

To evaluate the recent trophic state of Jinhae Bay, field campaigns were conducted in June and August during 2020-2023, measuring environmental factors in both the surface and bottom layers. Temperature differences between layers were greater in August than in June. Surface salinity was decreased in August, probably due to runoff, while bottom salinity remained stable. Dissolved oxygen levels showed a more pronounced stratification in August, leading to hypoxic conditions in the bottom layer. Chemical oxygen demand (COD) was higher at the surface, with rainfall contributing to elevated levels. The eutrophication index (EI) was consistently higher at the bottom across all stations, driven by dissolved inorganic nitrogen (DIN) and phosphate (DIP), with a notable increase in August due to organic matter decomposition. The trophic index (TRIX) was also higher in the bottom layer, with surface TRIX influenced by DIN and salinity, and bottom TRIX by salinity, rainfall, COD, and DIN. The average TRIX for Jinhae Bay was 4.21±1.30, classified as "poor", but comparable to values from other regions. Continuous monitoring of the trophic state is essential for the sustainable management of Jinhae Bay's fisheries.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.59-64
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• 2000

Heavy metal concentrations in surface sediments, seawater and oysters (Crassostrea gigas) were determined to assess heavy metal contamination in the Jinhae Bay. The ranges of cadmium, cobalt, copper, nickel, lead and zinc concentration in surface sediments were 0.1∼2.4, 12.6∼14.4, 25.3∼ 92.3, 32.4∼ 93.5, 24. 1∼81.2, 124∼477 ㎍/g, respectively. The concentrations of cadmium, copper, lead and zinc which were influenced by industrial activity were the highest in the inside of Masan Bay. Dissolved concentrations of cadmium, cobalt, copper, nickel, lead and zinc in seawater were <0.010∼0.043, 0.008∼0.120, 0.31∼0.90, 0.25∼3.10, 0.010∼0.142, 0.27∼9.04 ㎍/L, respectively. The concentrations of cadmium, cobalt, copper, nickel, lead and zinc in seawater were also the highest inside of Masan Bay, suggesting that Masan Bay is the major source of heavy metal input to the Jinhae Bay. Bioconcentration factors (BCF) of zinc, copper, cadmium, lead, cobalt and nickel in C. gigas were 647373, 280861, 145069, 44559, 13524, 2745, respectively, showing C gigas is a stronger accumulator than other bivalves.