• 한국패류학회지
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• 제32권2호
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• pp.133-139
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• 2016

The incubation time required for hatching of O. ocellatus were investigated through the processes of egg and embryonic developments by the dissecting microscopic and visual observations. And differences in ecological characteristics of the plankton mode of life or the benthic mode of life according to total numbers of the suckers on each short arm of the hatched juvenile larvae of O. ocellatus were studied by comparisons with other octopodidae species. Compared with the recent a few results reported by other researchers associated with the incubation time required for hatching by female adult mother of O. minor (73-90 days after spawning at $20.9-21.5^{\circ}C$ ranges), in this study, the incubation time required for hatching by female adult mother of O. ocellatus was 56-57 days after spawning at $11.0-20.4^{\circ}C$. Therefore, the incubation time required for hatching by female adult mother varied with Octopodidae species. In this studies, each ovarian egg laid by a female was connected to an egg string attaching to the surface of the wall or bottom of vacunt shell of Rapana venosa. Egg and embryonic developments of this species were studied in the indoor aquaria, in the specific gravity ranging 1.024-1.025. the hatched juvenile of O. ocellatus is 10.3 mm in the mean total length and 4.5 mm in mantle length, and each of its short arms has 18-20 suckers. The just hatched juvenile larvae of O. ocellatus enter the benthic mode of life (benthic larval stage) after hatching. In particular, regarding differences in ecological characteristics of the mode of life according to total numbers of the suckers, O. vulgaris may not need to have many suckers because they enter the planktonic mode of life after hatching, however O. ocellatus may need to have many suckers, because they should adapt to the benthic mode of life. And also the just hatched juvenile larvae of O. minor (bearing many suckers more than O. ocellatus) enter the benthic mode of life (benthic larval stage) after hatching. Therefore, the total number of the suckers on each short arm of the hatched juvenile larvae can be used for determining whether an octopus species has planktonic larval stages or benthic larval stage (benthic mode of life). In particular, The intracohort cannibalism phenomena appeared at the hatched juvenile larval stage because the larval stage of O. ocellatus and O. minor enter into the benthic larval stage in the early stage, unlike entering into the plaktonic larval stage in other Octopus species such as O. vulgaris: at this time, the early hatched larvae fed the late hatched larvae (they are the same species and almost same ages). Therefore, the intracohort cannibalism pheneomena occur in the just hatched juvenile stage of only O. ocellatus and O. minor.

• 대한수의학회지
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• 제33권1호
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• pp.109-117
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• 1993

This paper dealt with the situation and the hatch rate of bot's eggs on the equine hairs in Cheju horse with the species grouping of the bot flies of equine(genus Gasterophilus). The prevalence and infection dynamics of Gasterophilus spp. larvae was also evaluated in the equine alimentary canal submitted in this laboratory for the necropsy or from the abattoir. Samples including Gasterophilus spp. larvae, bot's flies and its eggs, which were collected from the alimentary canal and equine hairs, respectively, were studied and classified by morphology. The morphologic feature of the spines of Gasterophilus larvae were studied by scanning electron microscope. 1. Gasterophilus intestinalis larvae concentrated in the nonglandular portions of the stomach. The infection of second-, and third stage larvae were common in November, and from January to October, respectively. Gasterophilus nasalis larvae were commonly identified on the gastric pylorus and upper portion of duodenum. Second stage larvae were found from October to December, and 3rd stage larvae, from January to September. 2. The hatch rate of laid eggs of Gasterophilus intestinalis was 28.4%, and that of Gasterophilus nasalis was 79.5%. The hatch rate of Gasterophilus intestinalis eggs was highest(62.5%) in December. The hatch rate of laid eggs were higher in the region of scapula(64.0%) and limbs(62.5%) than on the maned hairs. The eggs of Gasterophilus nasalis were completely hatched by October. 3. Eight hundred five Cheju horses examined in this study were infected with the eggs of Gasterophilus spp. Gasterophilus intestinalis eggs on the body regions from sixty horses were recognized in phalangeal (14.4%), in abdominal(13.8%), metacarpal, brachial and cervical regions. Gasterophilus nasalis eggs were uncommon and recognized in submandibular regions(1.4%). 4. In conclusion, the infection of imago, larvae and eggs of both Gasterophilus intestinalis and Gasterophilus nasalis were indentified in cheju horse.

• Fisheries and Aquatic Sciences
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• 제21권12호
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• pp.37.1-37.10
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• 2018

The larvae and juveniles of Porocottus leptosomus belonging to the family Cottidae were collected (n = 95, 3.9-16.5 mm in body length, BL) from Busan, Korea, in March 2015. The larvae and juvenile were identified using DNA barcoding as P. leptosomus, and their morphological description was presented in detail. The yolk-sac larvae (3.9-5.6 mm BL) body was slightly compressed, the head was large, the eye was round and large, and the anus was before the middle of the body. The preflexion larvae (5.2-10.0 mm BL) body length drastically increased; caudal fin rays began to occur. The flexion larvae (9.4-11.8 mm BL) notochord flexion started; dorsal, pectoral, and anal fin rays began to occur; pelvic fin buds are seen; they possessed a pair of parietal spine; and a pair of supraocular cirri was first to develop. At 12 mm BL, the notochord was completely flexed. The larva stage (3.9-12.6 mm SL) had the stellate melanophores in the head, isthmus, gut, and tail (along to the ventral midline). During the juvenile stage (11.4-16.5 mm BL), melanophores covered the head and began to form five black bands on the side of the body. The larvae of P. leptosomus spent pelagic life, but moved to the bottom during the juvenile stage. The larvae and juveniles of P. leptosomus differ from other cottid larval fishes by body shape, melanophore head pattern, and spine development. P. leptosomus can be distinguished from Porocottus allisi by morphological development and the occurrence of larval fish: preopercular spine development, melanophore pattern, and caudal fin development.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.337-343
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• 2013

Post-thawed larval rearing in Pacific oyster Crassostrea gigas was performed to investigate the survival rate with time course in three kinds of larvae cryopreserved. The highest survival rate and larval activity index (LAI) of post-thawed larvae were obtained from the permeation in 0.2 M sucrose and 2.0 M ethylene glycol (EG) at $-1^{\circ}C/min$ in freezing speed showing the survival rates just after thawing of 63.8% in trochophore, 84.1% in D-shaped veliger and 56.3% in early umbo veliger. In post-thawed larval rearing with food supply, the larvae lasted their lives until 24 hours in trochophore, 75 hours in D-shaped veliger and 57 hours in early umbo veliger. The results suggested that each larval stage post-thawed revealed no more further development to subsequent respective stage.

• 한국동물학회지
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• 제4권1호
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• pp.13-20
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• 1961

우리나라 서해안인 경기도 부천군 선재도에서 산출되는 이매구류의 출현 빈도 분포 상태를 1959년 8월부터 1960년 10월에 걸쳐서 생태학적인 조사를 하였다. 1) Sampling 은 motor pump를 사용하여 원하는 깊이에 따라 각각 plankton을 채집하여 현미경으로 고나찰하여 KArvae 의 수를 조사하였다. 2) 각 stage의 larvae을 측정한 결과, 가장 어린 것은 60$\times$54$\mu$이었고, 가장 큰 것 은 320$\mu$336$\mu$이었다. 3) 이매구의 larvae 들은 수중에서 불규칙하게 분포하였다. 온도의 상승에 따라서 larvae의 분포는 증가되고, 대체로 온도가 하강함에따라서는 감소되었다. 4) 어린 stage의 larvae 수는 7월-9월 에 걸쳐 출현빈도가 높았다. 이것은 이시기가 선재도에 있어서는 이매구류의 산란시기라고 생각된다. 5) 8월-9월에 걸쳐서 대형의 alrvae의 출현빈도가 감소되는데, 이것은 larvae가 착생되었기 때문이라 생각된다.

• 한국잠사곤충학회지
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• 제29권2호
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• pp.15-23
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• 1987

경상남도잠종장에서 보유하고 있는 보유잠품종 23개 품종과 1986년 현재 우리나라 장려잠품종으로 지정되어 있는 16개 원종을 합한 39개 잠품종을 대상으로 유충의 행동반경을 조사한 결과는 다음과 같다. 1. 잠아의 행동반경은 품종간 차이가 현저하였으며 유충의 각령기에 따른 평균행동은 숙잠(9.24cm)이 가장 컸고 다음은 의잠(2.58cm)이었으며 3령(0.72cm)과 5령(1.18cm)은 극히 작았다. 2. 각 품종의 상대적 행동반경의 크기는 각 령기와 더불어 항상 일정하지는 않았다. 3. 1령, 3령 및 5령기에 있어서 각 품종의 계통별 행동반경의 분포범위는 유럽종계통의 경우 큰 것에서부터 작은 것에 이르기까지 폭넓게 분포하였으며 중국종계통은 그 범위가 좁았고 일본종계통은 그 중간이었다. 한편 숙잠기의 경우는 계통간 그 차이가 뚜렷하지 않았다.

• 한국양식학회지
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• 제20권3호
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• 한국어병학회지
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• 제23권3호
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• pp.421-427
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• 2010

Anisakid nematodes third stage larvae were isolated from the muscles of masou salmon (Oncorhynchus masou). Fish were purchased from Jumunjin fishery market in Gangneung. Four Anisakid third stage larvae were isolated from 4 fish. Molecular identification of the isolated worms was conducted by PCR-RFLP analysis of ribosomal DNA internal transcribed spacer region and direct sequencing of mitochondrial DNA cox2 gene. As results, all the tested individual worms were identified as Anisakis simplex (sensu stricto). This is the first report of molecular detection of anisakid worms in salmonid fishes in Korea.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.417-420
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• 2015

We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M dimethyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrification. After immersion into VSs and freezing, IGF-1R ${\beta}$-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular ${\beta}$-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability.

• Animal cells and systems
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• 제2권2호
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• pp.187-193
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• 1998

The four zoeal stages of Alpheus brevicristatus De Haan, 1849 are described and illustrated in detail from larvae roared in the laboratory. The larvae of A. brevicristatus was compared with those of the other Alpheus and a key to the first zoeal larvae of three Korean Alpheus species is provided.