• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.3
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• pp.103-117
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• 2017

This note provides technical guide on three issues associated with establishing and automatically running regional ocean forecasting systems: (1) a strategy for continuous production of hourly-interval three-day ocean forecast data, (2) the daily download of ocean and atmospheric forecasting data (i.e., HYCOM and NOAA/NCEP GFS data), which are provided by outside institutions and used as initial condition, surface forcing, and boundary data for regional ocean models, and (3) error notifications to numerical model managers through the Short Message Service (SMS). Guidance on dealing with these three issues is illustrated via solutions implemented by the Korea Hydrographic and Oceanographic Agency, since in embarking on this project we found that this procedural information was not readily available elsewhere. This technical guide is based on our experiences and lessons learned during the process of establishing and operating regional ocean forecasting systems for the East Sea and the Yellow and East China Seas over the 5 year period of 2012-2016. The fundamental approach and techniques outlined in this guide are of use to anyone wanting to establish an automatic regional and coastal ocean forecasting system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.1
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• pp.20-31
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• 2018

Marine parasitoid Amoebophrya infects and kills various bloom-forming dinoflagellates and strongly influences the harmful algal bloom dynamics. We investigated the effect of temperature on survival, infectivity, generation time of the parasite from the parasitoid Amoebophrya sp. and the harmful dinoflagellate host Akashiwo sanguinea system. Temperature had a significant effect on the parasite generation time and infectivity. While the lower temperature ($15^{\circ}C$) arrested parasite intracellular development and infectivity, resulting in the longer generation time ($115{\pm}0.1h$), the higher temperatures ($25^{\circ}C$ and $20^{\circ}C$) accelerated the parasite development, with the generation times of $58{\pm}0.1h$ and $83{\pm}0.1h$, respectively. Parasite prevalence (percent of host infected) was $71.5{\pm}0.30%$, $54.3{\pm}1.68%$, and $29.6{\pm}1.42%$ at $25^{\circ}C$, $20^{\circ}C$, and $15^{\circ}C$, respectively. These results suggest that biological control by parasitism on A. sanguinea bloom would not be highly effective during low water temperature season. Further, water temperature would be an important factor of bottom-up controls for the host-parasite population dynamics.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.505-513
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• 2010

This study investigate the characteristics of tidal constituents, and long-term mean sea level oscillations at Incheon bay. For this, the conditions of three tide stations around Incheon bay have examined, and carried out harmonic analysis on water level data for periods of about 40 years(1960~2007). Four major tidal constituents($M_2$, $S_2$, $K_1$, $O_1$) of each tide station showed tendency that change over the 18.61year lunar node cycle, and the type of tide at three stations is mainly semi-diurnal tides. And also, the past monthly tidal modulations are especially sensitive to the cumulative year of water level data in accuracy of tidal prediction. In case that regard the detached data at three tide stations as a single time series data of 40 years, the results of analysis on a single time series, long-term mean sea level oscillations and modulations of tidal datum at tide stations appears with a range of about 10cm, respectively. In addition, the predicted tides at the Inchcon harbor by global and regional tide models of OSU(Oregon State University) based on various satellite altimetric(Topex Poseidon, Topex Tandem, ERS, GFO) data are compared with the observed tides by KHOA(the Korea Hydrographic and Oceanographic Administration). The results show that the high resolution regional model is a quite good agreement at coastal shallow water region.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.13-20
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• 1998

The moving behaviour of Yellowtail Seriola quinqueradiata schools in the main-net of a large scale set-net was investigated in relation to the catching function of the funnel-net by a scanning sonar. The investigation was took place in the Kishihata set-net fishing ground located in Nanao city Ishigawa prefecture, Japan from Nov. 9 to Nov. 13, 1992. The obtained results are summarized as follows; 1. Fish schools showed the greatest number at the playground in the morning and at the bag-net in the afternoon. The fish schools remained long time in the main-net. 2. The rate of fish school through the funnel-net was smaller than that of fish school which is though the playground and bag-net. Because the Yellowtail school changed the shape of school in passing the funnel-net. 3. The rate of entering the bag-net was 24%, among the fish school heading to the outer funnel-net. But, the rate of escaping to the playground was 27%, among the fish school heading to the inner funnel-net. It seems that the structure of the outer funnel-net was not enough to lead the fish to the bag-net. However, the structure of the inner funnel-net was very effective at preventing escape. 4. It is appropriate to haul the net in the morning in considering the number of accumulated fish in the bag-net during the survey.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.247-254
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• 1991

Mackerel purse seine fishery is one of the most important fisheries in Korea and its annual mean catch from 1982 to 1988 is 350 thousand tons. Between 1982 and 1988, the characteristics of catch at 5 sectors of the sea area was analyzed according to operating sea block and the catch by fishes based on the data obtained from daily report of fishing condition that had been made out by 48 Korean fishing boats engaged in the fishery of purse seine. In these 5 sectors of the sea area, catch per net hauling in the coastal area of Cheju Island is less than that in the other sectors. Accordingly, the shape of fishing gear during operation has been measured to analyzed the deformation of net shape caused by the bottom current. (The lunar calender is used in the paper) The results obtained are as follows; The average CPUE of purse seines is 31.6 tons and it is higher from October to April than that from May to September. In the 5 purse seine fishing grounds, the ratio of net haul in the coastal sea area of cheju Island is 42.4% and it is the highest level, but the CPUE is 25.7 tons which is relatively low level. Each CPUE in the sea areas is significant differences with 1% level. Index of seasonal variation of mackerel CPUE from May to October is lower than the standard value, whereas index from November to January is higher. The diameter of circle by net shooting becomes shorter to the minimum caused by the bottom current during loose set, becomes narrower and the efficiency of fish encirclement becomes lower. The shape of leadline by bottom current becomes long oval type along with current direction in the tight set, while it becomes long oval type in the direction of a right angle to the current direction and the enclosed area is reduced hurriedly, and the deformation of net is most serious in the loose set.

• Journal of fish pathology
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• v.23 no.2
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• pp.211-219
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• 2010

Specimens were collected from the coastal region near industrial complex of Ulsan-Onsan, Sihwa-Ansan and Yeosu-Gwangyang in 2008 and 2009. The total number of individuals used in analysis was 1,289 of Acanthogobius flavimanus, Chelon haematocheilus, Hemibarbus labeo, Leiognathus nuchalis, Mugil cephalus and Synechogobius hasta. The sex ratio in the total individual was 1:0.73 (female:male). Specific sex ratio of fishes in the areas, namely the Ulsan-Onsan, Sihwa-Ansan and Yeosu-Gwangyang were 1:0.79, 1:0.81, and 1:0.25, respectively. Especially, female in Yeosu-Gwangyang was higher than male. The intersexuality in the total individual was 11.7%. Intersexuality of fishes in the areas were 4.98, 14.39 and 25.0% in the Ulsan-Onsan, Sihwa-Ansan and Yeosu-Gwangyang, respectively. It was indicated female higher than male in Ulsan-Onsan and male higher than female in Sihwa-Ansan and Yeosu-Gwangyang.

• Journal of fish pathology
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• v.26 no.3
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• pp.173-183
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• 2013

From July to early September 2012, there was mass mortality of fishes, particularly black rockfish, which were being raised in the floating fish cage along the coast of Gyeongsangnam-do. The amount of damage was 1,802,000 fishes and the causes were confirmed to be rapidly rising water temperature and repeated daily changes in water temperature. The water temperature in this area of the sea rose to the maximum $28.4^{\circ}C$ and the daily range of changes in water temperature was maximum $6.5^{\circ}C$. As a result of investigating biological diseases of 194 fishes in 49 fishery areas, major pathogenic organisms such as red seabream iridovirus (RSIV), Vibrio sp. and Vibrio spp. or Microcotyle sp. were detected in rockfish in some fish farms. It is considered that the major causes of the mass mortality were high water temperature accompanied by repeated daily changes in water temperature, it is considered that biological diseases influenced the increase in the perish of fishes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.489-499
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• 1998

Gonadal development, reproductive cycle and embryonic development of the marbled rockfish, Sebastiscus marmoratus were investigated histologically. A total of 1,035 specimens were collected from the Cheju Island from July of 1992 to May of 1996. Gonadosomatic index (GSI) in female reached the maximum during October to March, thereafter, the values decreased from Norvember to April. GSI in male reached the maximum in September (before one to three months of the female's maximum), thereafter, the values rapidly decreased from October to December. The annual reproductive cycle can be divided into five stages in female and four stages in male: females, Growing(June to September), Mature(September to February), Ripe and copulation(October to March), Gestation and parturition(November to April), Degenerative and resting(December to May); in males, Growing(April to July), Mature(August to November), Ripe and copulation(September to December), and Degenerstive and resting(November to March). Size frequency distribution of eggs and larvae showed non-synchrony. Maternal larvae parturition occurred one or two time during November to April. Mean length of the larvae parturition was 3.5 mm. Mean number of eggs and maternal larvae for the 15 cm minimum class of female was 58,377, and fecundity increased with the increase of total length and body weight.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.95-103
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• 1998

Acute and chronic responses to PCB toxicity of Neomysis awatschensis were studied by measurement of bioassay, growth, oxygen consumption and nitrogen excretion with concentrations of PCB at 10 and $20^{\circ}C$. 96 hr.-$LC_50$ at 10 and $20^{\circ}C$ were 28.7492 pub and 10.6742 pub, respectively. Survival rates during 60 days exposured to chronic PCB concentrations of 0.5 pub, 1.0 pub, 1.5 pub and 2,0 pub at $10^{\circ}C$ were $85\%,\;80\%,\;75\%$ and $75\%$, respectively and suwival rates at $20^{\circ}C$ $85\%,\;75\%,\;75\%$ and $65\%$, respectively. Average daily growth rate of N. awatschensis exposed to chronic PCB concentrations at $10^{\circ}C$ were 0.039 mm/day in control group and 0.036 mm/day at concentration of 2.0 ppb, while their rates at $20^{\circ}C$ showed 0.072 mm/day in central group and 0.039 mm/day at 2,0 ppb. The growth factors were some similarities between the chronic PCB concentrations, but intermolt periods were related to body size of mysids, temperature and PCB toxicity. Changes in oxygen consumption and nitrogen excretion rates during 60 days exposure to PCB toxicity showed higher in high groups of PCB concentrations. Assimilation and feeding rates of N. awatschensis fed Artemia sp. decreased with increase of PCB concentration at 10 and $20^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.104-108
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• 1998

Analysis of energy budget in Neomysis awatschensis exposed to PCB toxicity was carried out by measurement of bioassay, growth, oxygen consumption, nitrogen excretion at 10 and $20^{\circ}C$. Energy contents of the body, molted exoskeleton and eggs, which measured to understand used energy for growth, molt and oxygen consumption were 5.52cal/mg, 2.17 cal/mg and 6.15 cal/mg, respectively. Feeding energies at $10^{\circ}C$ were 3.755ca1 in control group and 3.420 cal at 2.0 ppb concentration, of them, $70.19\%$ and $67.53\%$ of their energies were assimilated. At $20^{\circ}C$, feeding energies were 5.998 cal in control group and 4.166 cal at 2.0 ppb concentration. The assimilation efficiency of the mysid estimated by ash-ratio method ranged between $11.5\~67.5\%$ and $73.4\~70.5\%$ with PCB toxicity at $10^{\circ}C$ and $20^{\circ}C$ respectively. Energy used by respiration of total assimilated energy was $45.18\%$ in control group and $62.27\%$ in 2.0 pub concentration at $20^{\circ}C$, and energy used by metabolism was high 2.0 ppb concentration than control group.