• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.189-194
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• 2009

To investigate the difference in the ecological niches between Pfiesteria piscicida and Pfiesteria-like species (Cryptoperidininopsis brodyi and Stoeckeria algicida), we have observed the feeding behavior of three potential predators on abalone larvae and measured the survival rates of abalone larvae as a function of initial predator concentration. When the predators were mixed with abalone larvae, P. piscicida and C. brodyi became active and exhibited attacking behavior on abalone larvae within a few seconds. They could ingest whole soft body of abalone larvae using a peduncle. In contrast, feeding and attacking behavior were not observed from S. algicida. Survival rates in abalone larvae decreased with an increase of the initial concentration of P. piscicida and C. brodyi. These results indicate that Pfiesteria and Pfiesteria-like species displaying the very same shape and size have different ecological niche in the marine food webs, which implies that identification to species level is definitely important to understand and discriminate the ecological roles of them.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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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.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.3
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• pp.223-231
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• 2020

Karyotype analysis is a major work in the process of triploid abalone production for the purpose of productivity and quality improvement. However, the metaphase spreads for karyotype analysis have been prepared just from the larvae at trochophore stage, which has restricted the spectrum of sample correction inhibiting more efficient analysis. Here, we investigated the feasibility of preparing metaphase spreads from the larvae at veliger stage that is the next developmental stage of trochophore. For this, diploid and triploid larvae at trochophore and veliger stages from Pacific abalone (Haliotis discus hannai) were subjected to metaphase spread preparation and its efficiencies were measured and compared each other. As the results, although the efficiencies of metaphase spread preparation were significantly lower in the larvae at veliger stage compared to the ones at trochophore stage regardless of ploidy status, we found that the preparation of metaphase spreads, which showed the clear chromosomal images containing the normal number of chromosomes, was possible from the veliger stage larvae. On the other hands, all larvae used in this study regardless of developmental stage and ploidy did not show colchicine sensitivity. Moreover, no significant difference was observed in cell cycle distribution of the cells comprising larvae between two developmental stages regardless of ploidy status. These suggested that the details of protocol to prepare metaphase spreads from abalone larvae should be optimized depending on its developmental stages. Taken together, we demonstrated the feasibility of preparing metaphase spreads from H. discus hannai veliger stage larvae for karyotype analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.591-595
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• 2003

Settlement of larvae, growth, and survival of juvenile abalone (Haliotis discus hannai) were examined after feding of 5 species of benthic diatoms (Cocconeis suctellum, Navicula sp Nitzschia longissima Bacillavia paxillifera, Licmophora flabellata). All of the benthic diatoms were isolated from natural populations on plastic plates for the abalone. The settlement of larvae, shell growth, and survival rate of juvenile abalone varied by diatoms species. The highest settlement rate of larvae was $43.1\%$ with the Cocconeis suctellum diet. Daliy growth rate reached a maximum at 64.1 ${\mu}m/day$ with the Navicula sp. diet and a minimum at 22.4 ${\mu}m/day$ with the Licmophora flabellata diet. Survival rate of the juvenile abalone was highest at $62.0\%$ with the Navicula sp., Cocconeis suctellum , and Nitzschia longissima diets. Survival rate of the Juvenile abalone was significantly higher than the control group with mixed diatom population diets (P<0.05). Therefore, diatom . species composition in diets can be a controling factor for the settlement, growth, and survival rates of Juvenile abalone.

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.122-135
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• 2024

Obesity is a disease involving mechanisms of fat accumulation, low-grade inflammatory cytokine release, and mitochondrial dysfunction. The aim of the current study was to investigate the effects of abalone intestine extract on fat metabolism in 3T3-L1 adipocytes and high fat diet-induced zebrafish larvae. The total phenol content was highest in subcritical water extract at 210℃ (SW210) among hot water, ethanol, and subcritical water extracts of abalone intestine. In addition, SW210 of male abalone intestine (MASW210) most effectively controlled the lipid accumulation and expression of adipogenic or lipogenic regulators (PPAR-γ, C/EBPα, SREBP-1c, and FAS) in 3T3-L1 adipocytes. Likewise, in zebrafish larvae fed high fat, MASW210 significantly suppressed body weight, glucose levels, and lipid accumulation. The mRNA expression related to adipogenesis (PPAR-γ and C/EBPα), lipogenesis (SREBP-1c and FAS), inflammatory cytokines (TNF-α and IL-6), energy m/;.etabolism (AMPK, lepr, SIRT1, and adiponectin), and mitochondrial biogenesis (PGC-1α and CPT-1) were significantly regulated by treatment with MASW210. These results suggest that abalone intestine extract such as MASW210, are useful biomaterials for improving obesity and metabolic diseases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.621-627
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• 2009

In order to standardize the juvenile abalone rearing technique, we selected sample farms by region in East, West and South coasts of Korea and Jeju island. We also have reviewed previous literature and visited farms to survey on the management of abalone juvenile production, spawning, hatching and so forth. Results of investigation are as follows: The light colors of tanks for larvae breeding are good for a frequent examination of larvae behaviour changes during the breeding period. The tank for the abalone juvenile production is a rectangular form in general and its size should amount to 3.5 m in length and 1.2 m width. It also should be built with proper drainage. The best age and size of adult for juvenile production are 3-6 years old individuals, with 9-12 cm separate burial and 125-150 g average weight. To induce spawning, the use of the exposure on air and ultraviolet ray together was the most effective. The density of larvae by plate should be 150-300 individuals and the proper stocking density was est imated and amount to 10-30 individuals. It has been shown that a correlation between water surface size($X_1$) and number of plates ($Y_1$), when producing abalone juveniles, is quite high and it is described by equation $Y_1=138.88X_1-5,736.8\;(R^2=0.9028)$. In addition, it has also been shown that a correlation between production of abalone juveniles ($Y_2$) and number of plates ($X_2$) is high and it is described by equation $Y_2=4.554X_2+12,493\;(R^2=0.8818)$. In Jindo region where a mass production of juveniles abalone has been done, it was shown, that a correlation between rearing water surface size ($X_3$) and production of juveniles abalone ($Y_3$) is very high and this relationship was described by the equation $Y_3=747.03X_2+94,359(R^2=0.9809)$. It has also been shown that a correlation between water surface size ($X_4$) and production of abalone juveniles ($Y_4$) in nationwide is high and the relationship between this variables was described by equation $Y_4=635.85X_4+99,923\;(R^2=0.9020)$.

• Journal of Aquaculture
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• v.12 no.3
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• pp.229-236
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• 1999

in the present study, the zinc toxicity to larval development and seed attachment of the abalone, Haliotis discus hannai was obtained under continuous flow through system. The zinc concentration melted from zinc coating pipe for 7 months ranged from $89.00\pm2.55 \mu\textrm{g}/\ell to 15.23\pm2.58\mu\textrm{g}/\ell(Y=0.85M^2-19.71+109.96)$. Treatments were carried out with zinc concentration $0~160 \mu\textrm{g}/\ell$. The maximum and minimum of fertilization rate were $87.7\pm5.3%$ in control, $83.7\pm7.6%$ in zinc concentration $160\mu\textrm{g}/\ell$, respectively. The maximum and minimum of hatching rate were $87.5\pm4.5%$ in zinc concentration $10\mu\textrm{g}/\ell$, $79.3\pm5.6%$ in zinc concentration $160\mu\textrm{g}/\ell$, respectively. Both of the results were not significantly different (P>0.05). But the normality rate, setting rate and survival rate of abalone larvae at over zinc concentration TEX>$20\mu\textrm{g}/\ell$ decreased rapidly and showed significantly different from those of the other group(P<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.268-275
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• 2009

The survival and growth of marine benthic invertebrate larvae such as abalone depend on the nutritional value of micro algae. However, it is difficult to determine the dietary value of the many microalgal species used for food by benthic larvae. Therefore, we tested the benthic copepod, Tigriopus japonicus, which grazes microalgae on substrata in a manner similar to abalone larvae. It also has short generation time and is easy to rear which makes to be easier to examine the dietary value of each micro algal species. We measured the daily production of nauplii from gravid females of T. japonicus fed 26 microalgal species separately. Amino acid and fatty acid content of the micro algae and the copepod was also analyzed. The nauplii production of T. japonicus was the highest (10.7) when they were fed Navicula sp. (B-394) and the lowest (0.8) when they were fed Scrippsiella trochoidea. In Tetraselmis suecica the nauplii production was so high (8.2), which was not significantly different with the diatom group. We determined that Navicula sp. (B-394), Rhaphoneis sp. and T. suecica were good sources of food for T. japonicus. We suggest that a diet of with a mixture of these three micro algal species may be also good for invertebrate larvae such as abalone.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.37-43
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• 2012

In this study, we invesgated a cytogenetic analysis of the Pacific triploid abalone, Haliotis discus hannai induced by low temperature treatment. We got a lot of mitotic metaphase chromosome spreads from the triploid and diploid Pacific abalones' hatched larvae (trochophores). The chromosome number of diploid abalone was 2n = 36 and that of triploid abalone was 3n = 54, so the chromosome number of triploid abalone was 1.5 times higher than that of diploid abalone. We developed a modified flow cytometric method for Pacific abalone from the existing methods. We uesd 51 months aged triploid and diploid Pacific abalones' hemolymph to get the DNA contents by flow cytometry. The DNA content of diploid abalone was 1.743 pg/cell and the DNA content of triploid abalone was 1.49 times higher than that of diploid one. It proved that triploid abalone was consisted with two sets of maternal diploid and one set of paternal genome.

• Journal of Aquaculture
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• v.8 no.3
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• pp.159-170
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• 1995

Triploid abalone, Haliotis discus hannai, was induced by the cold $(0^{\circ}C\;and\;3^{\circ}C)$ or the heat $(35^{\circ}C\;and\;40^{\circ}C)$ shock procedure with fertilized eggs, 12 min. or 32 min. post fertilization with the various time intervals of shock duration. Fertilization rate of each experimental group was not significantly different from that of corresponding diploid control (P>0.05). However hatching rates and normality rates of triploid larvae were significantly different from those of corresponding diploid control (P <0.05). In heat shock groups at $40^{\circ}C$, fertilization rate of eggs was extremely low $(0\~2.7\%)$ and hatched larvae were not detected in these treatment groups. Incidence of triploidy was confirmed by chromosome count and the highest rates of triploid $(84.0\%)$ revealed in cold $(3^{\circ}C)$ shock with 15 min. treatment duration 12 min. after fertilization. The number of diploid chromosome was 2n: 36, and that of tiploid was 3n=54.