• Journal of Aquaculture
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• v.7 no.2
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• pp.77-87
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• 1994

The study was conducted to develop the suitable abalone's diets for the indoor tank culture. The young abalone Haliotis discus hannai Ino sized ca. 20, 30 and 40 nun in shell length were fed three different diets, dried sea mustard Undaria pinnatifida HARVEY (control), artificial diet and terrestrial plants e. g. Chinese cabbage and Perilla leaf for 2 years. The growth rate of abalones fed an artificial diet was slightly higher than that of abalones from the control. However, the growth rate of abalones from terrestrial plants was significantly lower than that of abalones fed a control or an artificial diet (P< 0.05). The daily feeding rate of young abalones from terrestrial plants was slightly higher than that of abalones from the control. While, that of abalones from an artificial diet was approximately $30\%$ of that of abalones from a control or a terrestrial plants diet. The feed efficiency of abalone from artificail diet was higher than that of abalones from a control or a terrestrial plants diet, and the smaller size of young abalone showed the higher the feed efficiency. The EFA index values ${{\sum}n9/(20:4n6+20:5n3+22:6n3}$ of the dried sea mustard and the artificial diet were 1.26 and 3.64, respectively. These values were favorable, but the value of terrestrial plant, Perilla leaf was 127.00 indicating poor EFA index for normal growth of abalone.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.221-228
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• 2020

We studied the development of the endangered gold-spotted pond frog, Pelophylax chosenicus eggs and analyzed growth and survival rate of the tadpoles while feeding different feed to obtain the basic data on the its biological traits and reproduction. We observed the fertilized eggs of gold-spotted pond frog that naturally spawned in a breeding tank using a microscope. Fertilized eggs were sphere shape surrounded by colloid layers, clearly distinct with animal and plant poles. The fertilized eggs hatched 31 hours after fertilization and operculum complete at 175 hours after fertilization at water temperature of 27.0±1.0℃. As a result of growth and survival rate by different feed from 35 days after mouth open stage, vegetable feed (VF) group and tetra-min (T) group were significantly higher average weight gain rate (WG)(5843.9% and 5736.3%, respectively) and average specific growth rate (SGR) (11.67% and 11.62, respectively) compared with other groups (WG: 641.8~4625.2%, SGR: 5.72~11.01%). The vegetable (V) group showed the lowest growth rate (P<0.05). The average feed efficiency was 177.83% in the VF group, about 17 times higher than the V group. In addition, the average survival rate of the VF and T groups were the high at 97.5% and 100%, respectively, and the V group was the lowest at 32.5%. Therefore, the more efficient feeds for successful breeding is singly with VF or T.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.322-330
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• 2018

Herbivory is a major functional component of forest ecosystems, and herbivorous insects comprise about 25% of all insect species. Increasing plant diversity is related to herbivore abundance and diversity, which affects the level of leaf damage caused by insects. This study was conducted to identify plant-related variables such as plant diversity and number of leaves and density-related variables, basal area, and diameter at breast height (DBH) in a temperate forest of southern South Korea. To assess the level of leaf damage caused by leaf chewing insects, we set up two 0.1 ha plots in a temperate deciduous forest on Mt. Jirisan National Park. Plant richness differed between two sites: 16 species in 14 families(site 1) and 19 species in 15 families (site 2). Fisher's alpha index based on plant species richness and abundance resulted in 4.41 (site 1) and 6.57 (site 2). However, the sum of basal area of each site was higher in site 1 ($6.6m^2$) than site 2 ($3.7m^2$). The total surveyed leaves at two sites were 3,832 and 4,691, respectively and the damage leaves were 1,544 and 2,136, respectively. The mean leaf damage level was 11.2% (${\pm}1.76%$) in two study sites: the leaf damage level of the site 1 (11.99%) was significantly higher than site 2 (10.59%). Stepwise regression analysis showed that species diversity and evenness were the significant variables for leaf damages by chewing herbivores. NMDS ordination also identified that high tree density and low species diversity were the significant variables. This suggested that the level of damage was significantly higher in plots with low plant diversity and high tree density. In the future, we will investigate other guilds of herbivores such as sap-suckers, miners and gallers in temperate deciduous forests.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.1
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• pp.32-37
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• 2001

Fabrea salina is an euryhaline ciliate living at salt pond. Its size is small as ca. $150{\mu}m$, and its reproductive rate is high, so that this ciliate has been expected to be a new food organism which will be able to replace rotifer, Brachionus plicatilis. However, the dietary value of F. salina on fish larvae has not yet been verified thoroughly. This research was carried out to understand the mass culture technique and dietary value of this ciliate. In this study, six kinds of phytoplankton and three kinds of grain were tested on growth of the ciliate and optimum temperature, salinity and density of food were also examined for its mass culture. Regarding food for the ciliate, Heterosigma sp. and rice showed the highest growth among the phytoplankton and the grain, respectively. In this study, 229 ciliates per mL was cultured with Heterosigma sp., and 220 ciliates per mL with rice. The optimum temperature for F. salina was $33^{\circ}C$, and salinity ranging from 35 to 95 ppt had no significant difference on its growth. The optimum food density and amount for the ciliate were $5\times10^6$ cells/mL in Heterosigma sp. and 2.8 g/L in rice, respectively. With respect to dietary value of F. salina, six-day-old larvae of ayu, Plecoglossus altivelis, fed on the ciliate showed the high mortality over $96\%$ within 3 days, and it was significantly higher than those fed on rotifer. Even though the mass culture of F. salina has been achieved in the study, this ciliate seems to be inadequate as a food organism for fish larvae.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.260-261
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• 2000

잡식성은 대부분의 동물플랑크톤의 공통적인 전략임에도 불구하고, 식물과 동물성 먹이들의 에너지원으로서 화학적 유입에 대한 정보는 상대적으로 빈약하다. 비식물 플랑크톤 가운데 원생동물은 요각류의 번식 (reproduction)과 성장에 중요한 것으로 알려지고 있지만, 해양 무척추동물의 알이나 초기 유생단계가 요각류의 번식에 미치는 영향에 대한 연구는 거의 없다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.275-276
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• 2001

한반도에 자생하는 해산현화식물인 거머리말속 (Zostera, 잘피)의 거머리말 (Zostsra marina), 애기거머리말 (Z. japonica), 수거머리말(Z. caulescens)과 포기거머리말 (Z. caespitosa)들은 연안의 사질과 사니질에 생육하며 생태계에 중요한 역할을 담당한다. 이들 식물의 군집들은 조간대와 조하대에 침수 또는 노출되어 생육하면서 영양염과 중금속 순환에 중요한 역할을 수행한다. 식물체는 유기쇄설물을 먹이연쇄에 공급하는 기능을 하며, 중금속을 고등 영양단계로 수송하는 역할을 한다. (중략)

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.53-62
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• 2015

We surveyed butterfly community in a rural area of the southwestern part of Korea to investigate the changes of species composition and their abundances between 2001~2002 and 2014. The butterfly survey was conducted at the same site using a line transect method. There was a significant decrease of the numbers of species and individuals between 2001~2002 and 2014. We categorized each species based on six ecological traits: habitat type, habitat breadth, food plant type, food plant breadth, number of generation per year and overwintering stage. The comparison of number of species using these ecological traits showed no difference during the 10-yr time intervals. However, the comparison of number of individuals for the ecological traits showed the significant differences except for one trait, overwintering stage. We could suspect that the decrease of butterflies in the study area was resulted from the habitat change. To investigate the causal factors and the changes of butterfly fauna, we need a long-term monitoring of the local butterfly community.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5206-5210
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• 2012

We studied the effect of food concentration on grazing, growth and fecundity of cyclopoid copepod Paracyclopina nana. Marine phytoplankton Tetraselmis suecica was used as a livefood for the copepod. Six stage compositions were used and food concentrations for the experiment were 0.5, 1, 2, 5, 10, 20, 40, 60 and $80{\times}10^4$ cells/mL. Range of food concentrations with 0.2, 0.5, 1, 2, 3 and $4{\times}10^4$ cells/mL were used for nauplii production experiment. Grazing rates of P. nana in all developmental stages on the different concentrations were increased with increasing diet concentration. While the growth of nauplius was not affected by increase of food concentration, food concentration outside of $1{\times}10^4$ to $5{\times}10^4$ cells/mL range negatively affected that of copepodite. Daily nauplii production was increased with increasing food concentration but $3{\times}10^4$ and $4{\times}10^4$ cells/mL treatments were not significantly different with $2{\times}10^4$ cells/mL treatment. As a result, optimum concentration of T. suecica for mass culture of P. nana was considered to be 5,000 cells/mL for nauplius stage, 10,000 cells/mL for copepodite stage and adult male, 20,000 cells/mL for adult female, respectively.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.350-356
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• 2016

The biggest factor in the success of breeding animals is selection of foods, which is determined by quality and quantity of habitats(Newton, 2003), in the case of This high biomass wetlands as an indicator of ecosystem function about Common Kestrel's choice of hunting area is expected to be an important clue of quality and quantity of habitats. For this study, it is divided into four types(Glasslands, Paddy fields, Dry fields, Rparian land) about Common Kestrel's hunting area in Yugu-eup, Gongju-si, Chungcheongnam-do, Recorded the behavior of Common Kestrel for three years during the breeding season from March to June(2014~2016). Result of investigation, hunting area showed a high hunting behavior in riversides and flight-hunting was frequently investigated from may to June. In addition flight-hunting's main food acquisition is mammal(the vole), while perching behavior's main food acquisition is insect according to the fact flight-hunting were mainly done in riversides, perching behavior were highly investigated than flight-hunting at glasslands and paddy fields and dry field. Hunting spot's coverage rate of plants covering the ground showed differences depending on hunting areas, but height of plants were not significant. Height of the plant according to hunting methods of flight-hunting to catch mammal(vole) was analyzed to prefer lower height than perching behavior Based on these results riversides are considered as a very important environmental factors for Common Kestrel's prey selection in breeding session.

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.89-100
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• 2023

We investigated the spatial distribution of heterotrophic bacteria associated with different water masses in the northern East China Sea(ECS) in summer. The surface water masses were divided into the Changjiang Diluted Water (CDW) and high salinity water (HSW). In the CDW region, the concentrations of dissolved inorganic nitrogen (DIN) and chlorophyll-a (Chl-a), and micro Chl-a contribution were high; and bacterial abundance (BA) and ciliate abundance (CA) were also high. In the HSW region with relatively low DIN concentrations, Chl-a concentration and micro Chl-a contribution were low, but pico Chl-a contribution was increased compared to those in the CDW region. BA did not show any significant difference from the CDW region, but CA was decreased. BA showed a positive correlation with Chl-a concentration in the CDW region; however, it did not show a significant correlation with Chl-a concentration in the HSW region. The ratio of bacterial carbon biomass/phytoplankton carbon biomass was exponentially increased with a decrease in the Chl-a concentration. Compared to the past (1990-2000s), the surface phosphate concentrations and the size of dominant phytoplankton have recently decreased in the ECS. Considering this trend of nutrient decrease and miniaturization of the phytoplankton, our results indicate that changes in the strength of the oligotrophic water mass could alter the function of the microbial food web.