• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.103-103
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• 2002

This study was conducted to investigate cryopreservation of pearl oyster, Pinctada fucata martensii larvae. Four cooling rates (-0.25, -0.5, -0.75 and -1.0$^{\circ}C$/min.) were used to examine a proper cooling rate during cryopreservation of trochophores before seeding temperature (-12$^{\circ}C$). Seven developmental stages (early and late trochophores, early and late D-shaped larvae and early, middle and late umbo stage larvae) and different sugars (fructose, glucose and sucrose) were used to investigate optimal larval stage and effective sugar in cryopreservation of larvae. The survival rates of frozen-thawed trochophores increased at cooling rate of -1.0$^{\circ}C$/min. As larval developing, survival rate of frozen-thawed larvae increased, except umbo stage larvae, and especially late D-shaped larvae highly survived as 91%. Addition of sugar revealed positive effect on cryopreservation in this experiment and 0.2 M glucose and sucrose mixed with 2.0 M dimethyl sulfoxide significantly enhanced survival rate of larvae (P<0.05). The results of our study indicate that desirable cooling rate, developmental stages of larvae and effective sugar far cryopreservation of pearl oyster, P. fucata martensii larvae are -1$^{\circ}C$/min, late D-shaped larvae and 0.2 M glucose and sucrose, respectively.

• Parasites, Hosts and Diseases
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• 제35권3호
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• pp.211-214
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• 1997

중국산 수입 미꾸리에서 검출한 돼지악구충(Gnothostoma hispidum)의 유충(early third-stage larvae: EL3)을 10∼20개씩 비단잉어, 가물치 황소개구리. 마우스 및 흰쥐 등에 각각 경구 감염시킨 후 감수성을 관찰하였다. 총 40마리 및 45마리의 유충을 감염시킨 비단잉어 4마리와 가물치 3마리에서는 충체가 한 마리도 검출되지 않았다 유충을 총 30마리 감염시킨 황소개구리 3마리에서는 감염 후 2주에 위 및 장(8마리)과 간(1마리)에서 각각 검출되었는데 미꾸리에서 검출된 것과 같은 EL3이었다. 마우스 5마리에 유충을 각각 10마리씩 감염시키고 4주 후에 감염여부를 검사하였던 바. 총 37마리(74%)가 근육(31마리), 간(5마리). 신장(1마리) 등에서 검출되었다 유충 115마리를 흰쥐 9마리에 감염시키고 4주 및 8주 후에 충체를 회수하였던 바 총 40마리(34.8%) 가 모두 근육에서 검출되었다 이상의 결과로 중국산 수입 미꾸리에서 검출한 돼지악구충의 제3기 유충이 어류나 개구리에서 보다 마우스와 흰쥐에 더 잘 감염됨을 알 수 있었다.

• 생명과학회지
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• 제13권1호
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• pp.34-41
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• 2003

The hatching of fertilized egg and early development of larval black seabream, Acanthopngrus schlegeli by immersion of 3,5,3'-triiodo-L-thyronine ($T_3$) with doses of 0.01~0.5 ppm in tank were examined for early development periods and compared with control fish immersed by 0.1 N NaOH and 99% alcohol. Larvae were fed with rotifers for first 5 days during experimental period. Yolk absorption of larvae from $T_3$ immersion groups were significantly faster than that of control. Although hatching times among each groups were not significant difference. the hatching rates of larvae in higher doses (0.1 ppm and 0.5 ppm $T_3$ groups) were significantly lower than control. The results of $T_3$ immersion experiments to newly hatching larvae indicated that exogenous $T_3$induced significant faster the absorption of yolk and oil globule, faster the development of myotome and digestive duct and higher the growth rate of larvae than larvae of control. These results indicate that $T_3$ immersion supplements appear to confer a distinct advantage to eggs and larvae of black seabream, which is in early fragile developmental stage.

• Fisheries and Aquatic Sciences
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• 제14권4호
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• pp.339-345
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• 2011

Although culture techniques for the abalone Haliotis discus hannai are well known, mass culture of the benthic microalgae that are essential live food for the abalone larvae is still not practiced. This study was conducted to identify the microalgal species suitable for the growth of early larvae of H. discus hannai. The growth and attachment rates of 31 microalgal species were examined. Acrylic plates were used as the substrate. Among the 31 microalgal species, nine showing high growth and attachment rates were selected and tested for their dietary values via factors including settlement, metamorphosis, and survival rates of abalone larvae. Tetraselmis hazeni and Rhaphoneis sp. induced the highest settlement rate (65-69%) in abalone larvae. The metamorphosis rate was highest (57%) in larvae fed Rhaphoneis sp. and was also significantly higher in larvae fed Oscillatoria splendida (29%) and T. hazeni (22%) than in those fed other species. The highest survival rate of the larvae during the 15 days after metamorphosis was 67% in those fed Rhaphoneis sp., followed by T. hazeni (42%) and O. splendida (35%). In conclusion, Rhaphoneis sp. is the most suitable diatom for use as a live food for the culture of early larvae of H. discus hannai. In addition, T. hazeni and O. splendida are also potential species to be further developed and utilized in larval culture.

• 한국수산과학회지
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• 제56권1호
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• pp.44-53
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• 2023

In this study, the morphological development and early life cycle of larvae and juvenile Rhinogobius brunneus found in Wicheon, Nakdong River, Korea, were investigated. The fertilized eggs were 2.20×0.68 mm (long×short) in diameter. The eggs began hatching approximately 104 h after fertilization at water temperatures of 17.3-20.5℃ (mean 18.9±1.6℃). The newly hatched yolk-sac larvae were 3.71±0.06 mm in total length (TL), with an unopened anus. Three days after hatching, the preflexion larvae were 4.37±0.16 mm in TL with yolk absorption. Twenty days after hatching, the flexion larvae were 6.50±0.22 mm in TL and the tip of the notochord was bent upward. Twenty-seven days after hatching, the postflexion larvae were 11.8±0.63 mm in TL, and the tip of the urostyle was bent at 45°. Forty days after hatching, individuals measured 18.5±0.93 mm in TL and were considered as juveniles as the number of fins became constant for each part. All the postflexion larvae had detached fins. Additionally, the melanophore was observed to be distributed on the head, centrum of the body, and dorsal fin, and there was a difference in the morphology from the water stream.

• 한국수산과학회지
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• 제33권6호
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• pp.597-599
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• 2000

This study was performed to find out the cryoprotectants for cryopreservation of trochophores and early D-shaped larvae of surf clam, Spisula sachalinensis. Dimethyl sulfoxide (DMSO), ethylene glycol, 1,2-propanediol and methanol were used as cryoprotectant Each cryoprotectant was made to 1.0 M, 2.0 M, 3.0 M with dilution of 0.2 M fructose and 0.2 M sucrose. The trochophoers and early D-shaped larvae were immersed in each preparation for 10 minutes to reach equilibration and cryopreserved in liquid nitrogen. Survival rates of post-thawed trochophores and early D-shaped larvae in 2.0 M DMSO with 0.2 M sucrose were the highest as $91.4{\%}\;and\;78.9{\%}$, respectively.

• 한국해양학회지
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• 제14권2호
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• pp.54-60
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• 1979

가리비(scallop)는 한해성인 대형 조개류로서 우리나라 동해안에 분포하고 있으나, 영일만이나 영흥만과 같은 만 또는 그 부근에 특히 많은편이다. 가리비는 패주로서 중요할 뿐만 아니라 패각은 대규모 굴(oyster)양식의 부착기질로서도 중요하다. 우리나라에 있어서는 가리비 양식의 필요성이 크나, 양식의 기본문제가 되는 종묘생산 뿐만아니라, 이를 위한 기초연구들이 되어 있지 않다. 가리비의 양식적지라고 생각되는 우리나라 동해안을 대상으로 양식을 위해 현재까지 조사된 것은 1973년에 본대학 천해양식학연구실과 수산진흥원 포항지원의 공동조사 자료의 일부를 이등 (1977)이 발표한 것 뿐이며, 그 내용 중 부유유생에 관한 것은 4월 22일부터 6월 18일 까지 사이에 6회를 조사한 것 뿐이다.

• 한국수산과학회지
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• 제47권5호
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• pp.562-566
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• 2014

Larvae of pandalid shrimp Pandalopsis japonica are benthic, and may prefer bottom to planktonic food items. Three diets, enriched Artemia meta-nauplii (AR), clam meat (CM), and crumbled shrimp (CD), were evaluated as food for early larvae in terms of biometric growth R:D ratios. Larvae fed AR and CM had significantly greater total length and dry weight than did larvae fed CD (P<0.05). Survival was significantly greater in larvae fed CM than in those fed AR and CD (P<0.05). R:D ratios were also significantly higher in larvae fed AR and CM than in those fed CD (P<0.05). Planktonic Artemia meta-nauplii containing high levels of fatty acids and amino acids were not suitable for either normal somatic growth or survival at early benthic larval stages. Furthermore, it is necessary to determine the optimal feeding duration to increase digestibility of AD. Thus, we propose that clam meat is the best diet for pandalid shrimp larvae.

• 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.

• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.1-6
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• 2002

Effects on nonylphenol (NP) treatment on early development of fertilized eggs and survival of larvae in olive flounder, Paralichthys olivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solutions of NP at nominal concentrations of 50, 100, 150 and 200 $\mu\textrm{g}$/L. In the control I and II (methanol-carrier control) groups, the hatchability of fertilized eggs were 90.7$\pm$7.02 and 90.0$\pm$5.29％ (P <0.05), respectively. However, treatments of NP concentrations at 50, 100, 150 and 200 ug/L were reduced to 78.7$\pm$4.16, 46.0$\pm$9.17, 48.0$\pm$3.46 and 33.3$\pm$11.02% (P<0.05), respectively. The time to hatching of fertilized eggs was delayed in high-dose NP treatment groups rather than control groups. Fertilized eggs of NP immersed group could not hatch normally, and also vertebra of the larvae observed as abnormal shape. Cumulative mortality of hatched larvae after 26hr NP treatment was 38.3, 78.3, 88.3 and 100% in NP 50, 100, 150 and 200 ug/L treatment groups, respectively. Whereas, control I and II were 11.7, 16.7% (P<0.05). Hatched larvae showed most death at the embryonic development stage with abnormalities. These results suggest that NP treatment in fertilized eggs and larvae was inhibited as normally development for fertilized egg and growing of larvae.