• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.45 no.2
• /
• pp.96-105
• /
• 2009

For an effective management of fisheries resources, we need fisheries informations necessary for the establishment of reasonable fishing effort and TAC distribution. We carried out fishing research using trammel nets in the coastal sea of Susan-port(Yangyang, Gangwondo, Korea) and Hupo-port(Uljin, Gyeongbukdo, Korea) and analyzed fishing power variation of the fishing gear in terms of species composition, condition and so on for both sites. A total of 29 species were caught with most dominant species of Hippoglossoides dubius followed by Pseudopleuronectes herzensteini, Lophius litulon and Alcichthys elongatus in Susan. The total number of species caught in Hupo was 37 species with most dominant species of Todarodes pacifius followed by Lophius litulon, Hexagrammos agrammus and Pseudopleuronectes herzensteini. CPUE of Susan fishing area per trammel net was 12.74 fish and 2.00kg on average, while it was 6.80 fish and 2.27kg on average for Hupo. The fishing power index for both sites was 1, placing the two fishing grounds in a same level.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.3
• /
• pp.283-291
• /
• 2014

This study assessed dominant fish species, and the characteristics and spatio-temporal distribution of fish schools using acoustic and catch data in the marine ranching area (MRA) of Yeosu in July and August 2013. Acoustic data were collected using a 200-kHz dual beam transducer, and catch data were analyzed through auction data generated by a set net installed in the MRA. More fish schools were detected by acoustic methods in July than in August. The temporal distribution of fish schools differed between July and August, but, many schools demonstrated a high mean volume scattering strength (SV) around artificial reefs. Additionally, the characteristics of fish schools detected by echograms and the species caught by set nets differed between July and August. The dominant fish species were Engraulis japonicus, Pampus argenteus, Scomberomorus niphonius, and Pampus echinogaster in July, and approximately 85% of the catch in August consisted of Scomberomorus niphonius. Therefore, hydro-acoustic tools are useful for estimating fish school characteristics in large areas over a short period. To determine species, it is important to conduct net sampling surveys during the acoustic surveys. However, if a database of fish school characteristics organized by species is constructed through continuous study, it could be possible to identify fish species through acoustic methods alone.

• The Korean Journal of Ecology
• /
• v.18 no.4
• /
• pp.471-481
• /
• 1995

The weed population dynamics as affected by contrasting conventional tillege (CT) and no-tillage (NT) practices with a minimum herbicide application was studied in Athens, Georgia, U.S.A. Common chickweed (Stellaria media) was the most common spring weed while johnsongrass (Sorghum halepense), sicklepod (Cassia obtusifolia), and pigweed (Amaranthus retroflexus) accounted for 89∼97％ of net production during summers of 1983 and 1984. Total weed production in summer of 1984 was 2∼5 times greater than that of 1983. Weed production was greater in NT plots than in CT plots in summer of 1983, but reverse was the case in summer of 1984. In spring, net production in NT plots was greater than that in CT plots, especially, in 1985. Species diversity was consistently higher in NT plots, but in the wet summer of 1984 the pattern was different, with higher diversity in CT plots. Weed species diversity was higher in the spring rye crop than in the summer grain sorghum crop. The larger but less diverse weed populations in summer of 1984 indicated that these populations experienced competitive exclusion. Under the favorable summer moisture conditions the three dominant species grew so vigorously and quickly as to exclude many less common species that were able to survive under the drier conditions in 1983. The three dominant species not only excluded other weeds in 1984 but also greatly reduced crop production. The perennial johnsongrass was equally successful, or even more so, in CT plots as in NT plots. Plowing did not kill johnsongrass rhizomes but tended to break them up, thus increasing the number of individual plants that appear after the plowing. It means that johnsongrass was not controlled by the plowing. In summer of 1983, a moderate amount of weedy growth was maintained with a minimum amount of gerbicide application in NT and CT plots. It is possible that a small mixed weed population would be beneficial by providing cover for predatory and parasitic arthropods, and by reducing soil temperature and moisture losses.

• The Korean Journal of Ecology
• /
• v.24 no.1
• /
• pp.45-50
• /
• 2001

The fish fauna of the Buan Dam, Chollabuk-do, Korea which was constructed in 1995 was surveyed in 1994 and 1998. 14 fish species were collected in the Buan Dam and 19 species were recognized in the brackish waters along the lower course of the dam in 1998. It was remarked that the dominant species in the dam has been changed dramatically from Zacco platypus and Z. temmincki to Pseudorasbora parva and Squalidus gracilis majimae within the three years after the dam construction. And also the number of Carassius auratus and Sirulus asotus were gradually increased in the dam. However, lksookimia pumila, the threatened fish species of Korea, was decreased sharply and restricted conspicuously by fragmentation of the habitat. The positive strategies should be considered for the species conservation of lksookimia pumila in the Buan Dam.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.4 no.1
• /
• pp.41-51
• /
• 2001

'The Ecological Forest' in Youido Park was intended to be an artificial forest in urban center, following the form of natural forests in central Korea. This study was to investigate the planting plan and the vegetation change of 'the Ecological Forest' and to compare it with natural forests of similar plant composition. The natural forests had slopes between $12^{\circ}$ and $21^{\circ}$, whereas 'the Ecological Forest' had slopes between $2^{\circ}$ and $6^{\circ}$. It was unlikely that the slope condition was adequate to show 'toposequence succession' at 'the Ecological Forest'. The soil bulk density and soil hardness of 'the Ecological Forest' were higher than those of the natural forests. The soil pH of 'the Ecological Forest' was 7.45, which was greater than that of the natural forests. There were some changes in plant composition and amounts 2 years after the construction : the number of conifers was reduced from 383 to 338 ; the number of deciduous trees was reduced from 4717 to 1158. It was because of the young trees dead in the sub-tree layer. The herbaceous species planted were 14 families, 31 species, which increased to 37 families, 93 species after 2 years. In case of horizontal structure of vegetation, trees and shrubs were distributed evenly in the natural forests, whereas 'the Ecological Forest' showed uneven distribution with higher total density. In case of vertical structure of vegetation, the natural forests had distinctive layers with dominant species distributed in each layers. In 'the Ecological Forest', however, dominant species were only in tree layer. The natural forests had greater average tree height, tree density, however, and basal area than 'the Ecological Forest'. The results showed that there were some differences in the structure between 'the Ecological Forest' and natural forests. The management plan should be applied in order that the natural condition be restored in 'the Ecological Forest' by competition between plant species and natural processes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.39 no.spc1
• /
• pp.132-141
• /
• 2006

Artificial structures have been designed as pilot structures to promote the creation and restoration of tidal flats. However, little information is available as to whether such artificial construction affects the macrobenthic community structure. We monitored the variation of the macrobenthic community structure and species composition near natural and artificial structures (seaweed and a timber fence) on the tidal flats near the Iwon Dike, Korea. In total, 137 macrobenthic species were recorded during this study, predominantly crustaceans (47%), polychaetes (18%), and molluscs (27%). Polychaetes comprised over 50% of the total density, followed by gastropods (38%) and crustaceans (11%). Macrobenthic species composition in the artificial and natural areas, was initially similar, but it differed after 7 months. The gastropod Umbonium thomasi, the most dominant species, was present at both sites in the first month after the start of the experiment, but disappeared at the artificial sites within 7 months, suggesting disturbance by the environmental factors. The number of species and diversity (H') varied significantly within sites at the beginning of the experiment, but no difference was observed after 7 months. Multivariate analysis (multidimensional scaling) revealed significant differences in community structure between the artificial and the natural areas from 7 months after the start of the experiment, except from 18 to 21 months. The community structures were mainly influenced by U. thomasi. Community structure at the artificial sites was affected by environmental variables, such as carbon, COD/IL sulfide, loss of ignition, kurtosis and silt, which changed over time. We observed no significant correlations between environmental variables and the dominant species, except in the case of Spio sp. and Macrophthalmus dilatatus, suggesting that the biological interactions and temporary disturbances such as typhoon, as well as the effects of artificial structures may also be important regulating factors in this system.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.1
• /
• pp.39-47
• /
• 2008

The fluctuation in the abundance and species composition of fish was investigated using a fyke net with entrances on both sides in the coastal waters of Geumo-do, Yeosu, Chollanam-do, Korea, from May 2003 to April 2004. A total of 2,379 fishes (392.13 kg) were sampled and classified into 11 orders, 34 families, and 53 species. The dominant orders were Perciformes, Scorpaeniformes, and Pleuronectiformes, which accounted for 67.9% of the collected fishes. The dominant species was Acanthopagrus schlegelii (235 individuals, 19.00 kg), followed by Konosirus punctatus (182 individuals, 9.53 kg), and Apogon lineatus (161 individuals, 1.69 kg). The number of individuals and biomass were higher in spring and summer than in winter, and the monthly variation may be related to the water temperature. The diversity index was highest in September (H'=2.9) and lowest in December (H'=1.8). The evenness index was highest in August (J=0.9) and lowest in December (J=0.7). The dominance index was highest in December (D=0.7) and lowest in August (D=0.2). The economically important species in this area are Acanthopagrus schlegelii, Konosirus punctatus, Lateolabrax maculatus, Argyrosomus argentatus, Trichiurus lepturus, Lateolabrax japonicus, and Sebastes schlegelii.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.5 no.1
• /
• pp.1-7
• /
• 2002

The effects of floating islands on the changes in phytoplankton community structure were investigated in a small artificial pond. The floating islands planted with various emergent macrophytes covered 35% of total water surface area of the pond. Total 17 genera and 25 species of phytoplankton were found in the pond, of which Dinophyceae was 1 genera and 1 species, Cyanophyceae 1 genera and 1 species, Bacillariophyceae 6 genera and 8 species, and Chlorophyceae 9 genera and 15 species. Dominant phytoplanktons under floating islands were changed from Aphanizomenon sp. as a Cyanophyceae to Golenkinia radiata, Kirchneriella contorta and Micractinium pusillum as a Chlorophyceae for 56 days after the construction of floating islands on July 24, 2001. The changes of dominant phytoplanktons of the control without floating islands were similar to those under floating islands in July and August, but Aphanizomenon sp. was rapidly increased in the control sites in September. About 99% of the cell number of Aphanizomenon sp. was disappeared for a month after construction of floating islands. Species diversity of phytoplankton under the floating islands of Iris pseudoacorus was higher than those of other macrophytes as well as the control without floating islands. The cell numbers of Cyanophyceae and Chlorophyceae were fewer under the floating islands of I. pseudoacorus than those of other macrophytes. Our results showed that the floating islands could be a useful eco-technique for the control of water bloom by Cyanophyceae and Chlorophyceae in a pond ecosystem.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.3
• /
• pp.47-53
• /
• 1999

This study was carried out to suggest the slope revegetation technology of biological engineering using the Ligustrum obtusifolium, which is one of the pioneer plant species. Ahead of the experimental construction, we evaluated the L. obtusifolium's value of biological engineering for the slope stabilization by testing the growth rate after the cuttings were buried for 8 weeks('98. 7. ~ '98. 9.). In this test, it was found that the L. obtusifolium, one of the species deep rooted with developed underground parts, is very effective for the slope stabilization and that the rooting powder(Hormex Powder) gave the better effects on root germination. In April of 1999, the experimental construction of biological engineering technology using recycled L. obtusifolium live cuttings(applied growth-stimulating compound) and green bags was conducted at sandy cut-slope in GLEN ROSS G.C.(Yongin). The slope was tolerant of soil erosion despite of heavy rainfall in the rainy season and many plant species invading for five months('99. 4. ~ '99. 9.). The vegetation research was performed through examining the frequency of each block using the transect method. 21 kinds of plant speices appeared in total area($25.5m^2$) and the dominant species are Digitaria sanguinalis, Setaria viridis, Cyperus amuricus, Persicaria blumei, Artemisia princeps var. orientalis. With regard to life forms, therophytes were shown with a dominant distribution of 66.7% of total species and neophytes relatively with a low distribution of 19.0%. Furthermore, it can be estimated that there is no ecological stabilization of this slope with the result of the ruderal species' occupation of 71.4%. It is too early to argue about ecological mechanical advantages and disadvantages of this technology, but, from the result of this study, it is expected that the slope revegetation technology of biological engineering using L. obtusifolium can be effectively applied to sandy slope(not rock or weathered rock slope) and that the early rapid stabilization and favorable succession could be done with the improvement of soil condition.

• The Korean Journal of Mycology
• /
• v.40 no.3
• /
• pp.141-144
• /
• 2012

Total 50 species, 80 strains: Eighty strains of yeasts were isolated from wild flowers of Daejeon city and its surroundings in Korea. Isolated yeasts were identified by comparison of their PCR-amplified 18s rDNA V3 region or internal transcribed spacer-2 (ITS-2) genes with BLAST database. Among them, 32 species, 54 strains of yeasts were isolated and identified from wild flowers of Daejeon city, and Cryptococcus species were dominant yeasts. Furthermore, 18 species, 26 strains of yeasts were isolated and identified from wild flowers of Geumsan-gun and Nonsan-gun, Chungcheongnam-do in Korea, and also Candida species and Pseudozyma species were dominant yeasts.