• 주택과사람들
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• s.202
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• pp.48-51
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• 2007

가재울뉴타운은 강북의 대표적인 불량 주택 밀집 지역으로 2차 뉴타운 사업 지구 중 가장 빠른 사업 속도를 보이고 있다. 이곳은 2003년 11월, 2차 뉴타운으로 지정된 후 지난해 6월 가재울 2구역, 11월 가재울 1구역이 착공식을 가졌다. 서대문구의 새로운 주거 중심지로 변모될 가재울뉴타운을 찾았다.

• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.194-200
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• 1986

A study on the population density of crayfish intermediate hosts and infestation status of crayfish with encysted larvae of Paragonimus westermani in Ulchin county, Kyungpook Province, Korea was conducted from May to October in 1986. The population density of the crayfish ranged from 1 to 13, with an average of 4 per man-hour. Among the six habitats, Ducheon had a somewhat higher density than that of the others. Of eight hundred and seventeen crayfish examined, 127 or 15.5 per cent harboured the metacercarial larvae of Paragonimus westermani. The majority of the larvae were found in three parts of the body: most frequently in the cephalothorax, next in the gills, and then in the liver. The average number of metacercarial larvae per infected crayfish ranged from 1.0 to 1.9, with an average of 1.7. Summarizing the results, this study indicates that the population density of crayfish intermediate host and infestation rates for the crayfish with encysted larvae of Paragonimus westermani in Ulchin county of Kyungpook Province is relatively high.

• Animal Systematics, Evolution and Diversity
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• v.17 no.1
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• pp.35-47
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• 2001

The postembryonic development of the Korean crayfish, Cambaroides similis (Koelbel, 1892), was described in detail and compared with those of other known species of Astacidae and American Cambaridae, and phylogenetic relationship of the genus Cambaroides was discussed. Ovigerous females of the Korean crayfishes appear in May. Durations of juvenile stages 1 and 2 are two and four weeks at 15.0 $\pm$ 0.5$^{\circ}C$, respectively. From juvenile stage 3, it leaves from its mother. It is considered that C. similis is very closely related more to the Astacidae than to the Cambaridae in the characteristics of the maxillule of juvenile stage 1 and the antenna, maxilla, pleopod, and telson of juvenile stage 2.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.125-136
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• 1994

To characterize the SR Ca-release channel protein complex of crustacean, $^{45}Ca-release,\;[^3H]ryanodine$ binding, and immunoblot studies were carried out in the crayfish and/or lobster skeletal sarcoplasmic reticulum. Bmax and affinity of crayfish SR to ryanodine were lower than those of lobster SR. AMP (5mM) increased $[^3H]ryanodine$ binding significantly in both vesicles (P<0.05). $Mg^{2+}$(5mM) or tetracaine(1mM) inhibited $[^3H]ryanodine$ binding significantly in both vesicles (P<0.001), but ruthenium red $(10\;{\mu}M)$ inhibited it moderately. In SDS polyacrylamide gel electrophoretic analysis of crayfish SR vesicles, there was a high molecular weight band that showed similar mobility with Ca-release channel protein of lobster skeletal SR, but more rapid mobility (HMWBr) than that of rabbit skeletal SR (HMWBS). Immunoblot analysis showed that polyclonal Ab to lobster skeletal SR Ca-release channel protein was react with HMWBr of crayfish skeletal SR, but not with that of HMWBs of rabbit skeletal SR. ^{45}Ca-release from crayfish skeletal SR vesicles was increased by the increase of extravesicular calcium from $1{\mu}M$ to 1mM. This Ca-release phenomenon was similar, but more sensitive in the low concentration of $Ca^{2+}$, compared to that from lobster SR vesicles. AMP (5mM) or caffeine (10mM) did not affect to $^{45}Ca-release.\;^{45}Ca-release$ was inhibited slightly ($3{\sim}8%\;by\;Mg^{2+}$) (5mM) or tetracaine (1mM), and moderately (23%) by high concentration of ruthenium red $(300\;{\mu}M)$. From the above results, it is suggested that SR Ca-release channel protein of crustacean has different properties from that of the rabbit, and similar properties between crayfish and lobster in functional and immunological aspects, but Ca-release via crayfish channel may be more sensitive to calcium.

• The Zoological Society Korea : Newsletter
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• v.16 no.2
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• pp.5-8
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• 1999

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.521-526
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• 2017

In the GTA welding process of Al 7075 alloy using different types of filler metals, the tensile test and micro-hardness test were conducted to evaluate the mechanical characteristics. Also, the radiographic test result showed that the weld met the criterion of level 1 in accordance with KS D 0242 for verifying the welding integrity and there were no welding defects. The tensile test result obtained using Al 7075 as a filler metal showed that the material was fractured in the weld zone. The tensile strengths of the materials using Al 7075 and ER 4043 as the filler metal were about 240MPa and 253MPa, their yield strengths were about 132MPa and 120MPa and their elongation percentages were 6.6% and 13%, respectively. The micro-hardness value of the deposited metal zone when using Al 7075 as the filler metal was Hv 132. However, the micro-hardness of the material using ER4043 as the filler metal was about 24% lower than that using Al 7075. When the chemical composition of the filler metal is the same as that of the material itself, fracture can occur in the deposited metal zone. Therefore, it is not desirable to use the same material as the filler metal for the welding of Al 7075 alloy. Moreover, the use of Al-Si based ER 4043 as a filler metal is more desirable than using the same material as a filler metal for welding Al 7075.

• Journal of Aquaculture
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• v.22 no.1
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• pp.16-22
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• 2009

Life history of Korean crayfishes Cambaroides similis (Koelbel) was studied 8 month from March to October, 2006 from the Gwanak mountain, Seoul, South Korea. By capture and recapture method, 551 crayfishes were collected analyzed during the experimental period. Based on the distribution pattern of body lengths, the local population putatively divided into four age groups. The sex ratio of male and female was almost equal. However, their growth rates varied by water temperature. Early juveniles seen during June became adult during August. The study findings suggest that late autumn is mating season.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.368-380
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• 2022

Biomonitoring of an invasive alien crayfish species, Procambarus clarkii (Girard, 1852), was performed from February to October 2021, along with environmental DNA analysis, at five locations including Wanju-gun, Hampyeong-gun, Naju-si, Gurye-gun, and Cheongju-si. For the investigation, an umbrella-shaped trap for adults and a hand net for young crayfish were used, and 8 to 10L of freshwater was collected for eDNA analysis. The current status and past distributional records of crayfish in Korea were analyzed along with benthic macroinvertebrates at each survey site. As a result of the investigation, a total of 122 individuals were identified, and Hampyeong-gun recorded the largest number of populations with 59 individuals (48.36%) and the highest environmental DNA (eDNA). The frequency of appearance of P. clarkii was highest in May. The ratio of females to males was 21:5, and the body size was 72.2±21.1mm for female, 80.5±15.6mm for male, and 25.3±9.8mm for young crayfish. P. clarkii introduced into Korea is mainly spreading in the southwest region and it has not been observed in Seoul where there had been a record of appearance in the past. No external symbiosis (Branchiobdellida) of P. clarkii has been identified, and P. clarkii that has appeared in Korea was presumed to be imported from Japan. There are more than eight kinds of exotic crayfish distributed in Korea, and among them, the marbled crayfish (P. virginalis) was identified as a harmful species to the ecosystem of Korea by the Ministry of Environment in 2021. The identified species of benthic macroinvertebrates inhabiting the survey area where P. clarkii has appeared were 69 belonging to 39 families, 15 orders, five classes, and three phyla. Among them, Odonata were the most abundant (16 spp.; 24.62%), followed by Coleoptera (11 spp.; 16.92%) and Hemiptera (11 spp.; 16.92%). In the survey area, one Korean endemic species (Rhoenanthus coreanus), one species (Helophorus auriculatus) classified as Near Threatened (NT) on the Korean Red List, and six species of Crustaceans appeared. In the functional feeding group, the predators appeared predominantly while in habitat oriented group, the climbers appeared to be abundant. It was confirmed that P. clarkii in the survey area prefers an area rich in aquatic vegetation with waterside vegetation, and has high resistance to turbid water quality. The omnivore invader P. clarkii is expected to maintain a competitive relationship with carnivorous benthic macroinvertebrates that are predominant in the same species, and is expected to continue to generate ecosystem disturbance along the food chains.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.333-339
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• 2019

The Red swamp crawfish Procambarus clarkii is native to the southern United States and inhibits all over the world including the United States, Asia, Africa and Europe. In Europe, it is known to disrupt ecosystems such as competition with native crayfish. In this study, habitats of red swamp crawfish were identified in Jiseok stream (15.5 km section) and Daecho stream (6.1 km section) of Youngsan river. A total 33 red swamp crawfish were captured. A female captured in Jiseok stream carried 215 newly hatched red swamp crawfish in her the burrow. As a result of the analysis of the habitat environment, the water temperature was ranged of 2.4~32.8℃, conductivity was 53.4~502.3 μS cm^-1 and DO was 0.74~22.64 mg L^-1. As a result of measuring HOBO, the temperature ranged from -9~48.1℃, showing a change of 57.1℃ throughout the year. The variation of the water temperature throughout the year from 2.9~33.9℃ was found to be 31℃. Red swamp crawfish have a high adaptability and a wide range of environmental resistance, and report a sharp increase in newly invaded areas, negatively affecting indigenous organisms. In addition, it can be used as a medium for the spread of diseases and parasites, so prompt investigation and research should be carried out.

• 건강소식
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• v.18 no.5 s.186
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• pp.58-61
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• 1994