• The Korean Journal of Malacology
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• v.31 no.3
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• pp.165-170
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• 2015

The presence of predators (excluding starfishes) of disk abalone, Haliotis discus hannai was directly investigated by nine SCUBA divings during February-December 2014 at the coastal areas of Yangjeong, Jukjin and Bongpyeong, Uljin, Korea, where the young disk abalone seedlings were artificially released. The results revealed that a total of six individuals of Neptunea cumingii that were feeding on the young disk abalone were observed within the water depth 10m at the coastal area of Jukjin, of which bottom substrate consists of the relatively high composition rate of rocks (60.3%). Though N. cumingii is well known as a carnivorous predator of diverse marine invertebrates such as live mussels (Mytilus spp.) it is the first report that this predator also feeds on the disk abalones. Thus, our results strongly suggest that the future artificial release projects around Korean coasts necessitate extermination works of predators including newly observed N. cumingii in this study as well as previously known starfishes prior to the releases of young Pacific abalone seedlings.

• Journal of fish pathology
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• v.22 no.3
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• pp.293-303
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• 2009

Effects of stress on the low salinity stress were examined in the pacific abalone Haliotis discus discus. Changes in survival rate, hemolymph count, antioxidant enzyme activities (catalase: CAT and superoxide dismutase: SOD), respiratory burst activity, phenoloxidase activity, lysozyme activity and expression of heat shock protein 70 (HSP70) mRNA were measured 0, 3, 6, 12, 24 or 48hours after low salinity treatment with 25, 30, 33 and 35 psu. Survival rates of pacific abalone were 100% at 33 and 35 psu, but 93 and 97% at 25 and 30 psu for 48 hours, respectively. Hemolymph counts decreased in the time elapsed-dependent way at all of the experimental groups. At low salinity, 25 and 30 psu, SOD and CAT activity increased compared to the experimental group of 33 psu. Moreover, respiratory burst activities of the pacific abalone seemed to have no effect on low salinity stress at any experimental group. However, phenoloxidase activity is an important component of the defence against pathogen that was decreased in a reduction of salinity dependent way. Lysozyme activity also immediately reduced at 25 psu experimental group for 48 h. The HSP70 mRNA was weakly expressed at 33 psu, but strongly detectable at 25 psu experimental group. The HSP 70 mRNA expression in gill increased in the time elapsed-dependent way at 25 psu experimental group and then recovered at 48 h. These results suggest that low salinity stress give rise to inhibitory action of immune system as a result of the decrease of phenoloxidase and lysozyme activity in the pacific abalone, especially.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.248-253
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• 2020

The level at which analyses of DNA content might contribute more significantly to the genetic mechanisms of evolution lies in the events of speciation. The object of this study was to investigate the DNA content of abalone (Haliotis discus hannai) and determine the optimal tissue samples for measuring the DNA content of abalone by flowcytometry without fixation. The DNA content (pg/nucleus) of gill tissue (2.5±0.08), which was contaminated with protozoa, was significantly lower than that of muscle tissue (3.2±0.02), mantle tissue (3.2±0.02) (p<0.05), and a standard reference standard, while the DNA contents of muscle tissue and mantle tissue were higher than that of the standard reference. Considering the results of this study, DNA content analysis with flowcytometry is an acute and rapid method by which muscle tissue and mantle tissue are the most appropriate sample for measuring the DNA content of abalone without fixation.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.317-322
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• 2011

This study was performed to obtain the basic data on physiological responses of low water temperature stress of the cultured Pacific abalone, Haliotis discus hannai. Abalones were exposed at low water temperatures of $7^{\circ}C$ and $4^{\circ}C$. We have investigated survival rate, superoxide dismutase (SOD) activity and total protein (TP) in the abalone by the exposure times (0, 3, 6, 12, 24, 72, 120, 168 and 216 hours). Survival rate of the abalone at $7^{\circ}C$ experiment was 90.8%, whereas at $4^{\circ}C$ experiment was 0% after exposure 10 days. SOD activity was significantly increased until 12 hours after exposure to $4^{\circ}C$, and then was recovered to starting level after 24 hours. However, there was no significant difference between control ($12^{\circ}C$) and $7^{\circ}C$ experiments. TP was significantly increased until 216 hours after 24 hours at $4^{\circ}C$ experiment, but $7^{\circ}C$ experiment showed no significant differences compared to control ($12^{\circ}C$) experiment. Therefore, H. discus hannai was acclimated in low water temperature stress at $7^{\circ}C$, but at $4^{\circ}C$, all abalone died possibly because they exceed the limits of defense ability to too low temperature.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.415-419
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• 2014

Inbreeding depression may be an avoidable phenomenon for abalone culture. However, only a few studies were carried out on inbreeding depression. In the present study, to demonstrate inbreeding depression in growth trait of Pacific abalone, H. discus hannai, inbreeding and outbreeding families were produced in 2010. Inbred and outbred families from each experiment were reared in same tank until 10 month for the same breed environment. The individual of inbred and outbred were distinguished by paternity test using microsatellite DNA. The shell length between inbred and outbred families was compared. At the results, significantly higher shell length was observed in the outbred families at 10 mon (P < 0.05). These results indicate that inbreeding depression is obviously observed in growth traits in the first generation of full-sib family of the H. discus hannai.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.197-201
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• 2009

This study was conducted to investigate the genetic characteristics of wild population of Pacific abalone, Haliotis discus hannai in Dokdo island. We used six polymorphic microsatellite marker to investigate the genetic diversity and population structure. The loci Hdh1321 and Hdh512 had the highest number of allele (34 and 22 respectively) and loci Hdh145 and Awb083 had the lowest (5 and 7 respectively). The mean number of allele per locus was 14.8. The average observed and expected heterozygosities were 0.664 and 0.824 respectively, and the average $F_{IS}$ was 0.195. We compared the population genetic parameters of Dokdo population with previously published data of the same species. At the result, the parewise $F_{ST}$ test showed significant difference between the Dokdo population and six populations (published data), suggesting that the genetic relationship of Dokdo population was separated from six populations.

• The Korean Journal of Malacology
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• v.29 no.4
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• pp.325-334
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• 2013

The purpose of this paper is to compare and analyze family variations for growth-related traits of Pacific abalone, Haliotis discus hannai. Genetic parameters and breeding values were estimated using all measurement data like shell length, shell width, and total weight as 18-month-old growth traits of 5,334 individuals of selected third generation's Pacific abalone produced in 2011. Family variations of 865 individuals of the upper 10 families with the largest number were inspected. Overall mean in phenotypic traits of 18-month-old Pacific abalone which was investigated in this study showed 54.5 mm of shell length, 36.8 mm of shell width and 21.3 g of total weight respectively. And, variation coefficient of total weight was 51.0%, so variability of data was shown to be higher than 21.1% of shell length and 20.7% of shell width. The family effects showed significant difference by each family (p < 0.05), and heritability of shell length, shell width, and total weight was medium with 0.370, 0.382, and 0.367 respectively. So it is considered that family selection is more advantageous than individual selection. On the basis of breeding values of estimated shell length and total weight, to investigate distribution and ranking by each individual about the upper 10 families with the largest number of individuals, the values were used by being changed into standardized breeding values. Based on shell length, it was investigated that the individual number of the upper 5.4% is 152 and the number of the lower 5.4% is 8. In case of total weight, it was inspected that the individual number of the upper 5.4% is 164 and the number of the lower 5.4% is 1. Like these, phenotypic and genetic diverse variations between families could be checked. By estimating genetic parameters and breeding values of a population for production of the next generation, if they are used properly in selection and mating, it is considered that more breeding effects can be expected.

• Journal of Life Science
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• v.26 no.4
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• pp.406-413
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• 2016

Abalones are gastropod mollusks belonging to the genus Haliotis. Pacific abalones are regarded as a very important marine gastropod mollusk in Korea, Japan, China, and also in food industries around the world. In Korea, 6 species of abalone have been reported to occur along the coasts: Haliotis discus hannai, Haliotis discus discus, Haliotis madaka, Haliotis gigantea, Haliotis diversicolor supertexta, and Haliotis diversicolor diversicolor. This study was performed to discriminate the genetic variances by the partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) genes and random amplified polymorphic DNA (RAPD) analysis against four species of Pacific abalone (H. discus hannai, H. discus, H. madaka, H. gigantea). COI gene is reasonably well conserved and has been sequenced in various invertebrate taxa. The RAPD analysis technique is a relatively simple and low cost method that allows differentiation of taxa without the need to know their genomes. In this study, we investigated the genetic diversity, phylogenetic relationships within each species. The COI and RAPD analysis were able to distinguish between H. gigantea and the other three species. However, these analysis methods were inadequate to distinguish between H. discus and H. madaka. These results are believed to be able to provide a basis data for future hybrid breeding research by defining the genetically closely related four species of abalone, which is to develop new hybrid abalone for export using hybrid breeding.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.105-111
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• 2013

The gonadal development of triploid and diploid Pacific abalones, Haliotis discus hannai was histologically investigated in spawning season. Diploid abalones had matured oocytes and spermatozoa, but most triploid had spermatocytes or developing oocytes that was slightly retarded in gonadal development compared to diploid abalones. In spawning experiment of triploid and diploid abalones, spawning rates of diploid male and female were 100%, but those of triploid female was 50% and male was 25% respectively. Investigation of spawned abalone eggs and spermatozoa revealed that length of diploid sperms head were 17.47 ${\mu}m$, breadth of head were 10.31 ${\mu}m$, length of spermatozoa were 130.72 ${\mu}m$, but those of triploid spermatozoa were 11.83 ${\mu}m$, 7.89 ${\mu}m$ and 103.36 ${\mu}m$ respectively. Triploid spermatozoa were significantly small to diploid spermatozoa (p < 0.05). The eggs of diploid and triploid were not different in size. The cross experiment between oocytes produced by triploids and spermatozoa by diploids ($3n{\times}2n$ cross) revealed that no fertilization were occurred, and $2n{\times}3n$ cross also revealed same result.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.335-342
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• 2012

This study was conducted to estimation the selection response for growth-related traits in 31-month old of Pacific abalone, Haliotis discus hannai were born in 2008. In overall mean of surveyed traits and standard deviation showed $76.31{\pm}7.247$ mm of shell length, $49.48{\pm}5.307$ mm of shell width and $40.96{\pm}6.80$ g of total weight. The effect of sex and maturity were statistically significant in all traits include out a condition factor (p < 0.01). And In effect of sex, female were higher than male in all traits excepting condition factor, significantly. In correlation between breeding value and phenotypic value by each traits, showed rank correlation coefficient and simple correlation coefficient, which represented low positive correlation. A hopeful genetic improvement to the next generation showed 6.96 mm of shell length, 4.47 mm of shel width and 12.93 g of total weight. Therefor, It is considered that if considering properly selection intensity and selection ratio, efficient improvement could be made.