• Weed & Turfgrass Science
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• v.6 no.1
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• pp.11-20
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• 2017

Ninety species belonging to 28 families of weeds were identified in Korean rice fields. They were divided by eight provinces and 19 agro-climatic zones to be used as basic data of weed control. Looking at the regional weed occurrence, there were 52 species of 20 families in Gyeonggi, 37 species of 17 families in Gangwon, 41 species of 15 families in Chungbuk, 21 species of 12 families in Chungnam, 24 species of 13 families in Jeonbuk, 54 species of 21 families in Chonnam, 36 species of 20 families in Gyeongbuk, and 32 species of 16 families in Gyeongnam province, respectively. The most dominant family was Poaceae followed by Cyperaceae and Asteraceae. Mostly dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea, Scirpus juncoides var. hotarui, Eleocharis kuroguwai, and Sagittaria sagittifolia subsp. leucopetala with slight differences among the provinces. Although there were some differences in 18 climate zones from Taebaek sub-highlands to the southern part of the East Coast (except for the Taebaek Highland), the dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea and Scirpus juncoides var. hotarui. The most dominant family was Cyperaceae followed by Poaceae and Asteraceae. The differences of weed occurrence between provinces and agro-climatic zones were largely influenced by various weather conditions rather than the provinces. The changes in cultivation mode and herbicide use might influence as well.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.299-308
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• 2001

We examined the growth variation with water depth, interval between suspended lines and locality of seedling production of sea squirt. Halocpthia roretzi, measuring approximately $10.1\~15.3$ mm in tunic height, was cultured at the farm near Guryongpo, Pohang city from 7 January to 6 December 1998 (333 days). Growth condition depending on culture depth was most favourable at the depth of $10\~12$m, It was concluded that nutritional conditions were better at the depth since there was a greater mount of phytoplankton than at any other depth in the water column. Growth condition depending on distance between suspended lines was most favourable at the interval of 2 m and 2.5 m than at the interval of t m and 1.5 m, There was no significance difference in growth variation with locality of seedling. The seasonal variations in growth of tunic height, meat and total weight were correlated with temperature and chlorophyll a, In the depth of $10\~12m$ the rate of increase in tunic height was generally greatest in the growth period II ($244{\mu}m/day$) and IV ($338{\mu}m/day$), lower in the period I ($108{\mu}m/day$), and slightly increased during the period III ($185{\mu}m/day$). The water column have showed a typical seasonal pattern with temperature ranged between $12.07{\sim}24.14^{\circ}C$ and over $20^{\circ}C$ between July and September.

• Journal of Aquaculture
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• v.8 no.3
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• pp.195-207
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• 1995

In order to study the embryonic development and hatching of wild long shanny, Stichaeus grigorjewi, were caught with the gill nets in the East Sea of Korea, and stocked at indoor tanks to induce natural spawning in February 25, 1994 and February 16 to 24, 1995. They were already matured when stocked, and average body length (50.66 cm) and body weight (1,192.74 g) of 57 females and average body length (48.62 cm) and body weight (612.58g) of 43 males were recorded. Before stocking, they were inserted with identification tags(ID tags) in the dorsal muscle, and spawning was traced by the portable reader (Destron/lDl Ltd.) Forty females among 57 spawned successfully in the average of 4 days after stocking. Females spawned almost all eggs contained in the ovaries at one time in the form of an egg mass and averaging 227,200 eggs Per egg mass. The egg mass was oval in shape, translucent milky in color, 20.32cm long axis and 14.57cm short axis in size, and 803.7g in weight. Male parents guarded their egg masses and circulated water with the tail part of the body. Fertilized egg was spherical in shape, and their average diameter was 1.54 mm. Each egg had a containing single oil globule, and it's average diameter was 0.37 mm. The average water temperature was $13.2^{\circ}C$ and incubation times after fertilization were 5 hours 25 minutes up to 2-cell stage, 13 hours up to morula stage, and 66 hours 35 minutes up to embryo formation stage. Hatching rate was approximately 10 percent in 368 hours 50 minutes after fertilization, and approxionateoly 90 percent of eggs were hatched in 425 hours 30 minutes after fertilization.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.727-743
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• 1996

To know the floristic composition, vortical distribution and community structure of marine benthic algae inhabiting in the intertidal and subtidal zones of Yongil Bay, east coast of Korea, the study has performed using the quadrat method along a transect line from July, 1995 to June, 1996. In this area, a total of 144 species including 2 new red algae to Korea was found: 5 blue-green, 18 green, 20 brown and 101 red algae. The representative species throughout the year were Ulva pertusa, Gelidium amansii and Symphyocladia latiuscula. Dominant species were Sargassum thunbergii in spring, U. pertusa in summer and autumn. In winter, Chondrus ocellatus and Monostroma grevillei occurred dominantly. The standing crop exhibited mean value as $185.8g/m^2$ dry weight. Maximum value was recorded in spring $(267.3g/m^2)$ and minimum was observed in winter $(93.7g/m^2)$. Shannon's species diversity (H') and evenness (J') as maximum value were recorded in spring, whereas minimum values were shown in winter. Vertical distribution, rerognized by cluster analysis based on relative coverage of the species, could be divided into two or three algal groups except spring. In general, green algae (M. grevillei, Capsosiphon fulvescens, U. pefusa, Enteromorpha compressa) and brown algae (Sargassum fulvellum, S. thunbergii) were represented in the upper and middle zone and red algae (G. amansii, C. ocellatus, S. latiuscula, Crateloupia okamurae, Pachymeniopsis eilliptica) in the lower zone. The algal community varied according to season and environmental conditions. Particularly, seasonal variation of vortical distribution seemed to be affected primarily by water temperature. Also seasonal tidal level and tolerance of algal species to desiccation appeared to be associated with it in this area.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.4-24
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• 2009

This paper examined archaeological resources that discuss how Silla entered the Gangneung area, the coastal region along the East Sea that has been excavated most actively. Silla expanded its territories while organizing the its system as an ancient state and acquired several independent townships in various regions, stretching its forces to the East Sea area faster than any other ancient states of the time. In particular, many early relics and heritages of Silla have been found in Gangneung, the center of the East Sea area. Many archaeological resources prove these circumstances of that time and provide brief texts that are valuable for our interpretation of historical facts. In this respect, it was possible for me to examine these resources to answer my question as to why early relics and heritages of Silla are found in the Gangneung area. Based on my research on Silla's advancement into the Gangneung area, I have acquired the following results: How did Silla rule this area after conquering Yeguk in the Gangneung area? After conquering the Gangneung area, Silla attempted an indirect ruling at first. Later, Silla adopted a direct ruling system. I divided the indirect ruling period into two phases: introduction and settlement. In detail, Silla's earthenware and stone chamber tombs first appeared in Hasi-dong in the fourth quarter of the 4th Century and the tombs spread to Chodang-dong in the second quarter of the 5th Century. A belt with dragon pattern openwork, which seems to be from the second quarter of the 5th Century, was found to tell us that the Gangneung region began receiving rewards from Silla during this time. Thus, the period from the fourth quarter of the 4th Century to the second quarter of the 5th Century is designated as the 1st Phase (Introduction) of indirect ruling in terms of aechaeological findings. This is when Silla was first advanced to the Gangneung area and tolerated independent administration of the conquered. In the third and fourth quarters of the 5th Century, old mound tombs appeared and burials of relics that symbolized power emerged. In the third quarter of the 5th Century, stone chamber tombs were prevalent, but wooden chamber tombs, stone mounded wooden chamber tombs, and lateral entrance stone chamber tombs began to emerge. Also, tombs that were clustered in Hasi-dong and Chodang-dong began to scatter to Byeongsan-dong, Yeongjin-ri, and Bangnae-ri nearby. Steel pots were the symbol of power that emerged at this time. In the fourth quarter of the 5th Century, stone chamber tombs were still dominating, but wooden chamber tombs, stone mounded wooden chamber tombs, and lateral entrance stone chamber tombs became more popular. More crowns, crown ornaments, big daggers, and belts were bestowed by Silla, mostly in Chodang-dong and Byeongsan-dong. The period from the third quarter to the fourth quarter of the 5th Century was designated as the 2nd Phase (Settlement) of indirect ruling in terms of aechaeological findings. At this time, Silla bestowed items of power to the ruling class of the Gangneung area and gave equal power to the rulers of Chodang-dong and Byeongsan-dong to keep them restrained by each other. However, Silla converted the ruling system to direct ruling once it recognized the Gangneung area as the base of its expedition of conquest to the north. In the first quarter of the 6th Century, old mound tombs disappeared and small/medium-sized mounds appeared in the western inlands and the northern areas. In this period, the tunnel entrance stone chamber tombs were large enough for people to enter with doors. A cluster of several tunnel entrance stone chamber tombs was formed in Yeongjin-ri and Bangnae-ri at this time, probably with the influence of Silla's direct ruling. In the first quarter of the 6th Century, Silla dispatched officers from the central government to complete the local administration system and replaced the ruling class of Chodang-dong and Byeongsan-dong with that of Silla-friendly Yeonjin-ri and Bangnae-ri to reorganize the local administration system and gain full control of the Gangneung area.