• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.267-267
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• 2017

In Korea, the average air temperature has been elevated twice faster than the average global warming. And the climate warming is characterized by the smaller rise of air temperature in summer and the greater rise of air temperature in spring and winter. Therefore, the number of frost-free days to determine the cultivation ability of crops has increased by more than 15 days in 10 years according to climate warming. This climate warming trend has extended and is projected to extend not only the sweet potato growing season but also the sweet potato early cultivating area to higher altitude and latitude region. This study was carried out to evaluate the possibility of sweet potato double cropping in the southern island area of Korea by assessing the growth and yield performance of sweet potato cultivated at extremely-early and -late time. We had performed at Yokji Island Yokji Island($E128^{\circ}$ 18' $N34^{\circ}$ 36'), a representative specified complex area of sweet potato cultivation in southern Korea. As the test varieties, the major cultivars of the this region, Shinyulmi and early hypertrophic cultivars, Dahomi were used. The prior cropping were planted with PE film mulching on March 30 and April 10, and harvested after 110 days. So the succeeding cropping were planted without PE film mulching on July 25 and August 5 according to the harvesting time of the prior sweet potato and harvested after 120 days. As a control, it was harvested on September 15, 120 days after planted on May 15. Each experimental plot had an area of 12 square meters consisting of 4 beds, and was planted one at a time at intervals of 25cm. We had investigated growth characteristics - main vine length, node number, branch number, total vine yield, and tuberous root characteristics - tuberous root number, average weight, starch value, and etc. After harvesting, we analyzed the economic effects by examining the postharvest quantity, the input labor, the management cost, and the income. The total yield of marketable products in prior and succeeding cropping was 46~70% higher than that of control. The average unit price of sweet potato was 36% higher than the conventional culture, and the gross income increased by 98%, but the operating cost increased by 83%, and the farm income increased by 103%. There are considerations such as the difficulty of enlargement of cultivation area due to lack of labor in limited space and the need for watering measures due to spring drought. However, if the area of application for sweet potatoes double system is increased by 10%, it can be used as a new cropping system.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.280-280
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• 2017

In Korea, the average air temperature has been elevated twice faster than the average global warming. And the climate warming is characterized by the smaller rise of air temperature in summer and the greater rise of air temperature in spring and winter. Therefore, the number of frost-free days to determine the cultivation ability of crops has increased by more than 15 days in 10 years according to climate warming. This climate warming trend has extended and is projected to extend not only the sweet potato growing season but also the sweet potato early cultivating area to higher altitude and latitude region. This study was carried out to evaluate the possibility of sweet potato double cropping in the southern island area of Korea by assessing the growth and yield performance of sweet potato cultivated at extremely-early and -late time. We had performed at Yokji Island Yokji Island($E128^{\circ}$ 18' $N34^{\circ}$ 36'), a representative specified complex area of sweet potato cultivation in southern Korea. As the test varieties, the major cultivars of the this region, Shinyulmi and early hypertrophic cultivars, Dahomi were used. The prior cropping were planted with PE film mulching on March 30 and April 10, and harvested after 110 days. So the succeeding cropping were planted without PE film mulching on July 25 and August 5 according to the harvesting time of the prior sweet potato and harvested after 120 days. As a control, it was harvested on September 15, 120 days after planted on May 15. Each experimental plot had an area of 12 square meters consisting of 4 beds, and was planted one at a time at intervals of 25cm. We had investigated growth characteristics - main vine length, node number, branch number, total vine yield, and tuberous root characteristics - tuberous root number, average weight, starch value, and etc. After harvesting, we analyzed the economic effects by examining the postharvest quantity, the input labor, the management cost, and the income. The total yield of marketable products in prior and succeeding cropping was 46~70% higher than that of control. The average unit price of sweet potato was 36% higher than the conventional culture, and the gross income increased by 98%, but the operating cost increased by 83%, and the farm income increased by 103%. There are considerations such as the difficulty of enlargement of cultivation area due to lack of labor in limited space and the need for watering measures due to spring drought. However, if the area of application for sweet potatoes double system is increased by 10%, it can be used as a new cropping system.

• Journal of Aquaculture
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• v.20 no.1
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• pp.31-40
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• 2007

To find out the effect of the spat planting time and environmental factors in the arkshell, Scapharca broughtonii (Schrenck), we investigated the growth, survival rate of arkshell and habitat characteristics in Gamak Bay, Yeoja Bay and Saryang Island. We planted artificial spats of arkshell in Gamak Bay and Yeoja Bay at November 2004, and also planted domestic and Chinese natural spats in Saryang Island at March 2005. We measured growth, survival rate of arkshell, physiochemical parameters of the water mass (water temperature, salinity, dissolved oxygen, nutrients and chlorophyll a) and characteristics of the sediment (oxygen penetration depth, oxygen microprofiles, ignition loss and chemical oxygen demand) by monthly. The cumulative survival ratio of arkshell in Gamak Bay was the highest at December, whereas the ratio of arkshell in Yeoja Bay was recorded as 0% at October. The monthly growth rates of arkshell length in Gamak Bay and Yeoja Bay were the highest in May and the growth rate of the Korean arkshell in Saryang Island was higher than Chinese ones significantly. The high mortality (> 65%) of the arkshell in Yeoja Bay during summer probably caused by high water temperature, inflow of low salinity water, and low dissolved oxygen concentration in sediment. The concentrations of nutrient and sediment COD were considered to play an important role in the monthly survival ratio of arkshell in Gamak Bay and Sarayng Island. We suggest that the growth and mortality of arkshell might be influenced to the planting time of spat and the habitat characteristics.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.559-564
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• 2009

Purpose: Surgical reconstruction of an ischial soft tissue defect presents a challenging problem owing to a high rate of recurrence, especially paraplegic patients. Although various muscle, musculocutaneous and fasciocuta - neous flaps have been used in the reconstruction of ischial soft tissue defect, it is still debated which type of flaps are the best. We had performed a relatively durable adductor magnus perforator island flap based on the perforators originated from the first medial branch of the profunda femoris artery for coverage of ischial soft tissue defect where was not a region universally reconstructed by perforator flap. Methods: From August 2005 until January 2008, the adductor magnus perforator island flap had been used for resurfacing of the ischial soft tissue defects in a series of 6 patients (4 male and 2 female). Ages ranged from 26 to 67 years (mean, 47.5 years), and follow - up period from 13 to 26 months (mean, 16.7 months). Causes were 4 pressure ulcers, 1 cellulitis and 1 suppurative keratinous cyst. Results: The sizes of these flaps ranged from 12 to 18 cm in length and 7 to 9 cm in width. The flaps survived in all patients. Marginal loss over the distal area of the flap by infection was noted in one patient, which was treated successfully with a subsequent split - thickness skin graft. Average thickness of the flap was 0.94 cm, which was more thicker than other perforator flaps. Long term follow - up showed a good flap durability. Conclusion: In planning a reconstructive option of ischial soft tissue defect, the adductor magnus perforator island flap is a relatively large cutaneous flap with a durable thickness. With proper patient selection, careful vascular dissection and postoperative management, we recommend this flap is a good and suitable option for coverage of the ischial soft tissue defect.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.342-347
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• 2008

Mortality and growth rate of the soft coral, Dendronephthya gigantea, from Jejudo Island on the southern coast of Korea were investigated from February 2003 to October 2004 using SCUBA diving. 48 individuals with variable sizes of D. gigantea of the depth of 15m were tagged with flagging tapes and plastic films, and then monitored with two month intervals. The average mortality of two-month term for the study period was 50.4%, with the peak of 84.6% during the summer storms in August - October 2003. About the size class mortality, individuals of size class I(${\leq}$10 cm) showed the highest mortality, followed by size class III(>20 cm) and size class II(10 cm-20 cm). Growth rate did not show a seasonal pattern. For growth in length, individuals of D. gigantea grew about 3cm in average for two-month period, with a maximum growth of 6.4 cm which occurred in August - October 2003. For growth in diameter, individuals grew about 0.3 cm for 2 month term, with a maximum of 1.4cm in April - June 2004. Individuals of size class I usually grew faster than those of larger size classes. D. gigantea population in Jejudo Island was strongly affected by summer storms, which was due to annual event of summer typhoon. Never the less, it appears that the local population can be maintained by fast growth of the juvenile stage and active recruitment to compensate the high mortality caused by the summer disturbance.

• Journal of Life Science
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• v.34 no.2
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• pp.122-127
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• 2024

This study investigated the reproductive ecology and spawning of Hoplobrotula armata on the coast of Jejudo Island. Samples were collected from February to December 2019 and February to December 2020, with a total of 2,634 samples. The results of the investigation showed that total length (TL) ranged from 22.0 cm to 68.8 cm, and the body weight (BW) ranged from 66.5 g to 3,553.9 g. According to the development process of gonads and the gonadosomatic index (GSI), the spawning period of H. armata was from July to October. The relationship between TL and BW was BW = 0.0024TL^3.3278 in females and BW = 0.0035TL^3.2162 in males. The sex ratios of surveyed female to male H. armata was 1:0.71, with more females. At 50%, 75%, and 97.5%, the group maturities of H. armata were as follows: Females, 39.9 cm, 42.7 cm, and 49.4 cm; males, 37.6 cm, 40.4 cm, and 46.9 cm, respectively. According to monthly GSI and gametocyte (ovarian, testis) development stage observations of H. armata on the coast of Jejudo Island, they spawn once a year and are presumed to be summer spawners.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.4
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• pp.83-88
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• 2016

The use of consistent coastlines is an important element for the systematic management of maritime boundaries and the interests of local governments. The Hydrographic and Oceanographic Agency conducted a preliminary survey for consistent coastline production, since 2001. As a result, the length of coastline was different by year. Because of the lack of systematic management, the use of incorrect data, etc. We also changed the coastline on the sea chart to show on a digital map for realization of terrain expression method. However, there was a variation in shoreline length due to various surveying techniques and shoreline extraction methods. In this paper, the characteristics of Jeju-do coastline were analysed by using a modified divider method of fractal dimension. The accuracy of the vectorization was determined by converting the actual distance in the Public Survey Amendment for proper divider use. With 1:5,000 and 1:25,000 digital maps of Jeju-si and Seogwipo-si each fractal dimensions were calculated. Jeju-si=1.14 and Seogwipo-si=1.12 in 1: 5,000. Jeju-si=1.13 and Seogwipo-si=1.10 in 1: 25,000. Calculated fractal dimension were correlated to data from digital maps. It was considered that complexity and scale of coastlines affected. In the future coastline length statistics and minimum ratio of calculated coastline length to original length need to be determined for consistency of coastline length statistics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.83-87
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• 1972

The fresh-water shrimp, Macrobrachium nipponensis (DE HAAN) is one of the largest of the shrimp species and one of the most important types fo protein food in fresh water fisheries. It can be found from Cheju island in the touth to Chung-ju in river or swamp, in the north. The breeding of these shrimps was studied by Chun and Yu (1967) and the relative growth was reported by author (1970a), but they did'nt provide other ecological features widely found in their natural environment. Shrimps were collected from the Nak Dong River, near Pusan, Korea once a month, from March to December 1963. The following is a summary of the results. 1. Larvae hatch from May to September, mainly in the month of July. 2. The average sex ratio ($male/female{\times}100$) is $62.9\%$ and goes down during the spawning season and rises from fall to spring season. 3. The minimum size of the female with eggs is aproximately 4.2cm in body length 3.5 gr in body weight, and 1.5 cm in carapace length. 4. Most shrimps of 5.75-7.75 cm in body length lay eggs. 5. The dorsal spines of the rostrum are 10-16(mode13) in number and the ventral spines of the rostrum are 1-5 (mode 3) in number.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.52-56
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• 2016

A single specimen (700 mm in disc length) of Plesiobatis daviesi, belonging to the family Plesiobatididae, was firstly collected in the north-eastern coastal waters of Jejudo Island, Korea by using a bottom trawl on 24 October 2010. This species was characterized by having five pairs of gill openings, tail with one to three large spines, long snout length, long caudal fin, and pleated margin of nasal curtain. It is morphologically similar to Urolophus aurantiacus, but the former is distinguished from the latter by having longer caudal fin and snout length. We add P. daviesi to the Korean fish fauna and suggest the new Korean names, "Gin-kko-ri-huin-ga-o-ri-gwa", "Gin-kko-ri-huin-ga-o-ri-sok" and "Gin-kko-ri-huin-ga-o-ri" for the family, genus and species, respectively.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.29-45
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• 2015

Water chemistry and fish community, based on fish compositions and ecological characteristics(trophic/tolerance guilds and condition factor), were compared in Gucheon Reservoir($G_cR$) and Yeoncho Reservoir($Y_cR$). Chemical parameters of water quality such as BOD, COD, nutrient(N, P) and suspended solids indicated that water quality was better in the $Y_cR$ than $G_cR$, and the temporal variability in seasonal and interannual patterns were greater in the $Y_cR$. The greater variability was mainly attributed to intense dilutions of reservoir water by Asian monsoon rain during July-August. Fish guild analysis indicated that species diversity was higher in the $G_cR$ than the $Y_cR$, and that the proportion of tolerant and omnivore species were greater in the $Y_cR$. Regression analysis of body weight-total length showed that the regression coefficient(b value) was lower in the $G_cR$(2.15 ~ 2.40) than the $Y_cR$(2.59 ~ 3.14). Condition factor(K) of fish against the total length showed negative slope of Zacco temminckii, Carassius auratus, Pseudorasbora parva and Rhinogobius brunneus population in the $G_cR$, and a positive slope of Carassius auratus and Rhinogobius brunneus population in $Y_cR$. Overall, our data suggest that the growth of the fish populations, based on the length-weight relations and condition factor, reflected the trophic regime of nutrients and organic matter.