• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.9-18
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• 1995

The study made an observation on periodicity of oviposition, and the effects of nutrient and salinity in egg un larval development of Aedes togoi, and the results are summarized as follows: The 53.9% mosquitoes of one feeding laid eggs once, 26.9% laid hice and 19.2% laid three times. Autogenous rate of Aedes togoi reared in three different nutrient groups in larval stage was 6.9% in 0.8 mg/larva, 22.5% in 1.6 mg/larva and 44.4% in 2.4 mg/larva. The oviposition rate according to different salinity of the oviposition sites (0%, 0.5%, 1.0%, 2.0% and 4.0%) was 25.2% in distilled water, 36.2% in 0.5% salinity 23.5% in 1.0% salinity and 14.6% in 2.0% salinity. Developing period of the aquatic stage of male Aedes toBoi in $25^{\circ}C$ were shorter (10.73 days) than females (11.85 days). The most effective concentration of salinity for the developing period was 1.0% which took 9.25 days in males and 10.44 days in females. In the developmental status of the follicles according to nutrition in the larval stage, the numbers of follicles of groups fed 0.8 mg, 1.6 mg and 2.4 mg per larva were 180.7, 197.% and 202 respectively. The result of ovary dissection on the 1 with day after emergence, three different nutrition groups were in Christopher's stage IIa mostly; each 71.0%, 61.1% and 39.9% of the total follicles and autogenous females observed.

• Development and Reproduction
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• v.16 no.2
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• pp.145-153
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• 2012

Reproductive cycle of the small abalone, Haliotis diversicolor aquatilis which collected from Seong-san coastal waters, Jeju, Korea were investigated monthly from May 2006 to April 2007 using histological methods. The gonad index (GI) of male and female reached a peak in June ($70.72{\pm}5.20$) and July ($55.38{\pm}11.73$). Subsequently, GI decreased in September (Male, $21.27{\pm}2.91$; Female, $27.75{\pm}4.76$) and increased again in October (Male, $48.49{\pm}8.39$; Female, $51.36{\pm}7.47$), respectively. After that, GI gradually decreased. In March 2007, GI was reached the minimum (Male, $8.46{\pm}0.57$; Female, $9.69{\pm}0.88$). The reproductive cycle of female and male could be divided into six successive stages ; In female, multiplication (February and May), growing (February to May), mature (April to July), partial spawning (May to November), degenerating (October to December) and recovery (September to October and December to February) stage. In male, multiplication (February and May), growing (March to May), mature (April to July), spawning (June to November), degenerating (November to February) and recovery (September to February) stage. The yellowish granular cells have been observed more in multiplication, growing, degenerating, and recovery stage than mature and partial spawning stage. The results of GI and histological observations of the gonads suggested that this species could be presumed as multi- spawning characteristics more two times in spawning seasons.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.17-25
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• 1998

A fisheries biological study on the hairtail (Trichiurus lepturus LINNAEUS), which was collected from Cheju City, Hanrim, Sungsanpo and Seogwipo in Cheju Island, was carried out from June through December In 1992. GSI of the hairtail maintained relatively high from June to September, and then it began to decrease in October and remained low until December. The maturation and spawning period was between June and October, and the major spawning occurred in August. The hairtail turned out to be a multiple spawning species which spawn two or three times In a single spawning season. During the spawning season the number of females was greater than that of males, whereas the sex ratio was almost 1 : 1 during the rest of the season. Fecundity estimated from various sizes of the hairtail ranged from 12,821 to 125,876. The bigger the snout anal length and body weight of the hairtail was, the more eggs it possessed.

• Journal of Aquaculture
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• v.17 no.1
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• pp.30-38
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• 2004

To estimate the spawning period the annual change of gonadosomatic index (GSI) were examined from January 2000 to December 2001. Fecundity, spawning frequency and egg diameter were measured by ocular observation. Germ cell differentiation during gametogenesis, the reproductive cycle and the first sexual maturity of greenling Hexagrammos otakii were observed under light microscopy from January to December, 2000. GSI began to increase in August and reached the maximum in November when ovary was getting mature. The reproductive cycle of H. otakii can be divided into five successive stages in females: early growing stage (July), late growing stage (July to August), mature stage (September to October), ripe and spent stage (September to December), and recovery and resting stage (December to June). Males showed four successive stages : growing (June to August), mature (August to October), ripe and spent (September to December), and recovery and resting stage (December to May). According to the frequency distributions of egg diameter in spawning season, H. otakii could be one of polycyclic species spawning 2 times or more during one spawning season. Number of total eggs and mature eggs in the absolute fecundity were related to the standard length and body weight, respectively. Number of total eggs and mature eggs in relative fecundity were also proportional to the standard length, but rather these numbers decreased with body weight. Percentages of first sexual maturity of females and males in greenling were over 50% from 19.1 to 21.1cm in length, and 100% for fish over 25.1cm in length. Therefore, both sexes are ready to reproduce after one year old.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.382-383
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• 2003

해만가리비(Argopecten irradians)는 미국의 대서양 연안과 걸프만이 원산지로 중국에서는 1982년 미국에서 이식한 이래 많은 양식생산이 이루어지고 있으며, 우리나라에서는 1996년 국립수산과학원 남해수산연구소에서 새로운 양식품종으로 개발하고자 최초로 이식하여 실내에서 인공종묘생산으로 치패를 생산한 바 있다. 국내에서는 연구로는 동절기 성장(Oh and Jung, 1999), 밀도별 성장(Oh et al. 2000), 양식 생물학적연구(Oh, 2000), 수심별 성장(Oh et al., 2002) 생식주기(Oh et al., 2002), 선발효과(Oh et al., 2002)등에 관한 연구를 수행한 바 있으며, 외국에서는 산란 및 생식상태(Loosanoff and Davis, 1963; Taylor and Capuzzo, 1983; Hampson and Capuzzo. (중략)

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.20-24
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• 1990

A fast convergent solution to the scattering problem of a transverse electric (TE) plan wave by a periodic strip grating with a dielectric slab is considered. The present method follows from an expansion of the equivalent surface magnetic current placed over the shorted slot according to the equivalence principle in a series of Chebyshev polynomials satisfying the appropriate edge condition. To examine the accuracy and convergence of the present method, the numerical results are calculated for the reflection and transmission coefficients and compared with other results available in the literature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.509-519
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• 1987

Annual reproductive cycle of the Damselfish, Chromis notatus collected monthly at the four coastal areas around Chejudo, Korea are studied on the bases of histological observations of gonadal tissue and various quantitative variables including gonadosomatic index (GSI), fatness, egg diameter composition and the first maturity. The ovary consisted of a pair of saccular structure with many ovarian sacs. Oogonia proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophilic cytoplasm showed several nucleoli along the nuclear membrane. When the oocytes reached about $450{\mu}m$ in diameter, nucleus migrate toward the animal pole, nuclear membrane disappeared and most of cytoplasm were filled with yolk materials and oil drops. After ovulation, residual follicle and growing oocytes remaining in the ovarian sacs degenerated. But early young oocytes without follicle layer were not degenerated, and growing continuously till the next year. The testis consisted of a pair of lobular structures in the right and left were united in the posterior seminal vesicle. Cortex of testis was composed of many sperm ducts connected with lobuli. GSI began to increase from March, starting season of longer day length and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between October and February without any evident variation. The annual reproductive cycle could be devided into five successive stage : growing(April to Many), mature(May to August), ripe and spent (June to August) and recovery and resting stage(September to March). The spawning peak occurred from June to August. According to the frequency distribution of egg diameter, Chromis notatus was a polycyclic species to spawn twice or more in a spawning season. Fatness, correlated with gonadal phases, was remarkably decreased by spawning. Percentage of the first maturity . in femate and male fish ranging from 7.0 to 7.9 cm were $50\%$ and from 9.0 to 9.9 cm in total length $100\%$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.161-172
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• 1997

In this paper, electromagnetic scattering by a perfectly conducting strip grating on dielectric multilayers is analyzed for the normalized reflected and transmitted power by applying the Fourier-Galeakin moment method. The induced current density is expanded in a series of multiplication of chebyshev polynomials of the first kind and functions with appropriate edge boundary condition, the continuous condition of electromagnetic field is applied in the boundary planes. The confirm the validity of the proposed method, the nor- malized reflected and transmitted power obtained by varying the relative permittivity and thickness of each dielectric layers are evaluated and compared with those of the existing numerical method and a paper, and then the numerical results in this paper are in good agreement with those of the existing numerical method and the paper. The sharp variation position in the geometrically normalized reflected and transmitted power can be moved by the incident angle, grating period, and the relative permittivity and thickness of the dielectric multilayers, these sharp variation points which are called the Wood's anomaly of the Geome- trically normalized reflected power are observed as a main factor when the reflected powers of the higher order mode are transitted between propagating and evanescent modes, and the local minimum positions are slightly moved to the left hand direction in which grating period is getting small according to the increase of the relative permittivity of dielectric layers.

• Journal of Aquaculture
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• v.21 no.4
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• pp.331-338
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• 2008

Monthly changes in the gonadosomatic index (GSI) and hepatosomatic index (HSI) of wild river puffer Takifugu obscurus, and water quality environment in spawning area during breeding season were investigated from March 1995 to February 1996. Monthly changes in GSI and HSI of T. obscurus, that was cultured in low salinity, were calculated. The external morphology of the gonads, germ cell differentiation during gametogenesis and the reproductive cycle with the gonad developmental phases were investigated by histological analysis. The optimum water quality environment in Ganggyung, Choongcheongnam-do, where is spawning ground of wild T. obscurus, was $15-20^{\circ}C$ (water temperature) and 0 psu (salinity). Monthly changes in the GSI in females and males reached a maximum in May, and then rapidly decreased. Therefore, it is assumed that in the natural condition the spawning period of wild T. obscurus is May to June. In females and males, it showed a negative correlationship between the GSI and HSI. The external morphology of the gonads in female and male T. obscurus, that was cultured in low salinity, is composed of a pair of saccular structure. Based on monthly changes in the GSI, it is assumed that in female T. obscurus, that was cultured in low salinity, spawn from March through May. Therefore, it showed a negative correlationship between changes in the GSI and HSI. On the whole, in females and males, it showed a similar pattern between wild and cultured T. obscurus. The reproductive cycle with the gonad developmental phases can be classified into successive five stages in females: the early growing stage, late growing stage, mature stage, ripe and spent stage, and recovery and resting stage. In males, that can be divided into successive four stages: the growing stage, mature stage, ripe and spent stage, and recovery and resting stage. In case of wild T. obscurus, the spawning period has once a year, however, those cultured in the high water temperature ($20-27^{\circ}C$) - low salinity (under 3.3 psu) condition have reproductive characteristics having possibilities of discharge of eggs and sperms year-round as a multiple spawner.

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.191-199
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• 1998

The ovary of the spotted flounder Verasper variegatus is a conical bag in shape and is bilateral structure develops lengthily from the posterior of the abdomen to the end of the anal fin. The testis also is bilateral in structure, usually located in small size in the abdomen. In females, the gonadosomatic index (GSI) showed very low from March to July, and then began to increase from August, thereafter reached the maximum in January through out the year. In males, the GSI reached the maximum (1.7) in January through out the year, as seen in females. Compared with the male GSI in other fishes, the maximum GSI of this species were very lower than those of other fishes. According to the distributions of egg diameter in the spawning season, it is assumed that the spotted flounder spawn four times or more in the spawning season. The total length of female and male reached 50% first sexual maturity were 42.0~44.0 and 28.0~30.0cm, respectively and total length of female and male reached 100% maturity were 44.0 and 32.0cm, respectively. The reproductive cycle could be classified into four successive developmental stages: growing stage (August~October), mature stage (November~December), ripe and spent stage (December~February), degenerative and resting stage (March~July).