• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.110-117
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• 2012

Hatching date and early growth of Pacific cod Gadus macrocephalus were estimated by examination of otolith microstructure of Pacific cod juveniles collected in Jinhae Bay of Korea from May to June, 2008. Water temperature during the main spawning time ranged from 7 to $9^{\circ}C$ according to the geographic distribution of temperature measured from November to May between 2006 and 2009. The spawners were collected from December to February between 2006 and 2008, and the gonadosomatic index of spawners was larger in females than in males, showing a peak in January. Total length of juveniles ranged from 37.5 to 94.9 mm ($63.2{\pm}11.0mm$; mean${\pm}$SD). The number of daily growth increments in juvenile otoliths were on average $102{\pm}15$ in May 17 samples, $119{\pm}16$ in May 29 ones and $116{\pm}18$ in June 3 ones. Hatching dates estimated from the number of daily growth increments ranged from late December to mid-March, showing the peak between late January and mid-February. Daily growth in total length (TL, mm) can be adjusted to the Gompertz curve: $TL_t=123.2{\exp}\{-{\exp}[-0.0165(t-81.8)]\}$ ($r^2$=0.93, n=273).

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.269-277
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• 2011

Age and growth pattern of Pacific cod Gadus macrocephalus were determined using samples collected in Jinhae Bay in Korea during the spawning period from 2006 to 2009. The ages of 333 specimens were estimated using their otoliths. The reliability of scales as a means of age determination was analyzed by comparing the ages estimated from otoliths and scales of 96 specimens. The scales collected from the base of the second dorsal fin or from the caudal peduncle were proved to be suitable for age determination of Pacific cod. Monthly changes in the marginal index in otoliths decreased from December showing the lowest value in February. Ages ranged from 4 to 6 years for both females and males, and most of them were 6 years old. Relationships between the otolith radius (R) and total length (TL) were TL=10.4R+3.1 for males, and TL=11.5R+3.4 for females. The growth curves in total length ($L_t$, cm) were expressed as $L_t$=141.5 [1-exp{-0.089 (t+0.209)}] for males and $L_t$=127.5 [1-exp {-0.124 (t+0.077)}] for females.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.223-228
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• 2010

High-frequency bottom loss measurements for grazing angle of $82^{\circ}$ in frequency range 17-40 kHz were made in Jinhae bay in the southern part of Korea. Observations of bottom loss showed the strong variation as a function of frequency, which were compared to the predicted values using two-layered sediment reflection model. The geoacoustic parameters including sound speed, density and attenuation coefficient for the second sediment layer were predicted from the empirical relations with the mean grain size obtained from sediment core analysis. The geoacoustic parameters for the surficial sediment layer were inverted using Monte Carlo inversion algorithm. A sensitivity study for the geoacoustic parameters showed that the thickness of surficial sediment layer was most sensitive to the variation of the bottom loss.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.76-90
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• 2018

To determine the distribution of mercury (Hg) in the coastal surface sediments around the Korean peninsula, the baseline concentration of Hg was estimated, the extent of contamination was assessed, and the factors controlling the distribution were discussed. The concentrations of Hg in surface sediments were significantly high in Jinhae-Masan Bay in the South Sea, Ulsan-Onsan Bay and Yeongil Bay in the East Sea, but Hg in other sediments showed a similar distribution to Cs and relatively very low concentration between 0.21 and $39.5{\mu}g/kg$ ($13.6{\pm}7.80{\mu}g/kg$). Compared to the sediment quality guidelines in Korea, 8 % of the surface sediments (n=282) analyzed in this study exceeded the values of the threshold effects level (TEL), and six sediments collected around Onsan Port were higher than the value of the probable effects level (PEL). The contamination levels of Hg were assessed by the enrichment factors using the baseline concentration (2.06Cs+1.75) based on the residual analysis from the linear regression line for Cs, and further, factors controlling the distribution of Hg were discussed by the comparison with geochemical substances depending upon the Hg enrichment level. Hg concentrations were correlated well with Cs concentration in the range of less than 1.69 of EF implying grain size control, while in the range of 1.69 and 4.03 Hg concentrations were correlated well with Fe oxyhyroxide and organic carbon contents, which indicates Hg was enriched by superior sorption capability. On the meanwhile, samples with higher EFs (4.03 to 74.9) showed fairly positive correlations with other metals (Cu, Zn, Pb) rather than geochemical substances. For samples in Youngil Bay and Ulsan-Onsan Bay (n=30), Hg concentrations were correlated only with other metals rather than geochemical substances implying simultaneous supply of metal particles from metal refineries. But samples at Gosung, Sokcho and Uljin coast were correlated well with organic carbon even though they had high EFs. In addition, samples in Jinhae-Masan Bay with high contents of S were enriched by relatively high sulfide formation.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.147-154
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• 2006

Effects of water temperature, salinity and irradiance on the growth of toxic dinoflagellate Alexandrium catenella (AlCt-01) were investigated, which was isolated from Jinhae Bay, Korea. The maximum growth of A. catenella strain was obtained at $150{\mu}E\;m^{-2}s^{-1}$. The ranges of temperature and salinity for the growth of the strain were $15\sim25^{\circ}C$ and $20\sim34$ PSU. The maximum growth rate of A. catenella determined was $0.45d^{-1}$ at $20^{\circ}C$, 30 PSU and $150{\mu}E\;m^{-2}s^{-1}$ We also examined the Se and Fe effects on the toxic dinoflagellate A. catenella in optimal growth conditions. As Fe concentration of medium increased from 0 to $11.7{\mu}M$, growth rate of A. catenella increased and the maximum growth rate(k=0.48 $d^{-1}$) was obtained at $11.7{\mu}M$ of Fe cone. Growth of A. catenella were stimulated at> 1nM of Se.

• Animal Systematics, Evolution and Diversity
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• v.28 no.3
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• pp.192-207
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• 2012

To supply the morphological and ecological information of oligotrich ciliates in Korea, water samples were seasonally collected in Gwangyang Bay and Jinhae Bay from August, 2010 to February, 2012 and processed by quantitative protargol staining method. As a result, six species belonging to the genus Strombidium Clapar$\grave{e}$de and Lachmann, 1859 are identified: Strombidium emergens Kahl, 1932; S. dalum Lynn et al., 1988; S. epidemum Lynn et al., 1988; S. tressum Lynn et al., 1988; S. bilobum Lynn and Gilron, 1993; S. pollostomum Lynn and Gilron, 1993. These six species were newly reported from Korean coastal waters. Strombidium emergens is a middle sized Strombidium ($20-50{\mu}m$ in length) and has open and deep oral groove to girdle portion. Strombidium dalum is a small sized Strombidium (${\geq}20{\mu}m$ in length), that has torch-like spiral anterior membranelles and an inverted triangles-shaped macronucleus on the posterior pole. The small sized S. epidemum has conspicuous trichites surrounding the girdle portion and ventral membranelles distinctly separated from anterior membranelles. The small sized S. tressum has torch-like spiral and extremely long trichites among the cilia of anterior membranelles. The middle sized S. bilobum has a bilobed macronucleus. Strombidium pollostomum is also a small sized Strombidium but its ventral membranelles are continuously connected with anterior membranelles. The five species except S. emergens occurred frequently over the wide range of water temperatures and salinities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.561-569
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• 2012

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were <1.8-16.5 and 1.8-246.8 MPN/100 mL and <1.8-7.1 and 1.8-74.8 MPN/100 mL, respectively. The samples, including those taken from stations located in Wonmunman, Gwangdo, and Dangdong, showed high levels of microbial contamination caused by the climate and weather patterns in the marine environment. The bacteriological water quality in the area met Korean criteria for a designated shellfish growing area for export and National Shellfish Sanitation Program criteria for an approved shellfish growing area, except at station #49. A total of 24 direct pollution sources were discharged into the shellfish growing area. The radius of impact was calculated for each pollution source to assess the effect on the shellfish growing area. The calculated radius of impact for most of the pollution sources was below 300 m. However, the radius of impact for the combined pollution sources in Kyeonnaeryang was 93-1973 m. There were significant differences between the calculated closed sea area and actual monitoring results. The closed sea area values calculated from the fecal coliform load in drainage water tended to be higher than the actual monitoring results. Tidal currents and environmental factors such as salinity, water temperature, sunlight, and microbiological factors affect the survival of fecal indicator bacteria in seawater.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.359-369
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• 2007

Amoebophrya is an obligate endoparasitic eukaryotic dinoflagellate infecting host species and eventually killing them within a short period. Because of its host specificity and significant impacts on population dynamics of host species, it has long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). For several decades, the difficulties of culturing host - parasite systems have been a great obstacle to further research on the biology of Amoebophrya but recent success of several culture systems reactivates this research field. In this study, as a preliminary work for understanding the impacts of Amoebophrya on the population dynamics of host species, semimonthly occurrence of infected host dinoflagellates by Amoebophrya spp. had been observed in Jinhae Bay for two years and with a host - parasite system cultivated, host specificity of Amoebophrya spp. on several dinoflagellates was tested. Amoebophrya spp. were observed in the cellular organelle and cytoplasm of several species including Akashiwo sanguinea, Ceratium fusus, Dinophysis acuminata, Heterocapsa triquetra, Oblea sp., Prorocentrum minimum, P. triestinum, Scrippsiella spinifera, and S. trochoidea. Among them two host - parasite systems for an athecate dinoflagellate, A. sanguinea, and for a thecate dinoflagellate, H. triquetra, had been able to be successfully established as laboratary cultures. Cross-infection tests for 6 species of dinoflagellates in which Amoebophrya was observed or had been reported to exist confirmed high preference for host species of the parasite. Through the continuous research on Amoebophrya occurring in Korean coastal waters, we need to maintain various host - parasite culture systems, which will be very helpful for understanding its ecological role in marine food webs and for applying the species to biologically control harmful algal blooms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.465-471
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• 2012

To compare the accumulation of paralytic shellfish poison (PSP) in different marine organisms, the occurrence and variation of PSP were surveyed in blue mussel Mytilus edulis, oyster Crassostrea gigas, short neck clam Ruditapes philippinarum, bay scallop Argopecten irradians, and warty sea squirt Styela clava collected from Jinhae Bay, Korea, in 2005 and 2006 year. We also investigated the ability of the blue mussel to detoxify PSP by relaying and depuration (via the water flow or water circulation system). In the marine organisms examined, PSP levels were the highest in blue mussel, followed in order by bay scallop, oyster, short neck clam, and warty sea squirt. Comparing the maximum PSP levels in the bivalve species examined in 2005 and 2006, PSP in blue mussel was 1.6-2.0, 4.0-5.9, and 5.1-6.0 times higher than in bay scallop, oyster, and short neck clam, respectively. Therefore, blue mussel could be useful as a bioindicator for PSP monitoring. With the increasing PSP levels in blue mussel in 2006, the proportion of PSP in its digestive gland increased to 95.1% when the maximum level was detected from the whole tissues of blue mussel on May 29. Subsequently, the PSP proportion in the digestive gland decreased as the PSP level in whole tissue decreased. The detoxification of PSP in blue mussel was greatest with relaying, followed by the water flow, and water circulation systems. Relaying decreased the PSP level below the regulatory limit of $80{\mu}g$/100 g after 2 days in low toxic sample with $124{\mu}g$/100 g, and after 7 days in high toxic sample with $401{\mu}g$/100 g. During depuration in the blue mussel with $401{\mu}g$/100 g via the water flow system, the PSP amounts in the digestive gland decreased by about 50% after 1 day, and about 77% after 7 days. In contrast, the PSP amounts in the soft body, gill, and mantle did not change significantly with depuration.

• Korean Journal of Microbiology
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• v.21 no.2
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• pp.79-85
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• 1983

Ammonia oxidation activity of polluted water samples in Jinhae Bay and isolated strain from the seawater was investigated, and effects of environmental factors such as temperature, salinity, substrate concentration to the ammonia oxidation were also investigated. The ammonia oxidation activities of sediments, 0.01-0.04mg eq. $NO_2-N/l/h$, were exceptionally higher than that of sea water, $0.5{\sim}1{\mu}g$ eq. $NO_2-N/l/h$. the activities of muddy sediments at station 4 and 2 were 0.03~0.04mg eq. $NO_2-N/l/h$ and that of sandy sediment at station 3 was 0.002mg eq. $NO_2-N/l/h$. In the case of sea water, the activity of polluted area, station 1, was 2 times higher than that of offshore, station 4. The isolated strain reached log phase after 30days culturs and its oxidation activity was $2{\sim}3{\mu}g$ eq. $NO_2-N/day$. The maximum oxidation of ammonia by IA 13 strain occured at 30mg/l oxidation increased with the salinity rising up to 100% seawater concentraion. And temperature for maximum oxidation of ammonia was $35^{\circ}C$. the oxidation increased with the salinity rising up to 100% seawater concentration.