• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.90-97
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• 2020

The purpose of this study was to provide basic information on sexual maturity and reproductive biology for the management of biological resources in abalone Haliotis discus hannai. The nucleus of the oogonium occupied about 42% of the cytoplasm, and had a distinctive basophilic chromatin. The cytoplasm of previtellogenic oocytes was homogeneous and the size of nuclear pores increased. Fine granular and vacuolar yolk granules were observed in the cytoplasm of the initial vitellogenic oocyte. In this stage, the egg stalk and jelly membrane began to develop. The nucleus of the active vitellogenic oocyte was located near the animal pole. Yolk granules were strongly acidophilic. Lampbrush chromosomes were observed in the nucleus and rough endoplasmic reticulum. Annulate lamellae developed in the cytoplasm. The shape of the ripe oocyte was rounded polygonal. The size of ripe oocytes was 202.9±21.40×142.1±18.82 ㎛ and the thickness of the jelly membrane was 10.1±1.52 ㎛. These results show that yolk accumulation in H. discus hannai is based on two methods: exogenous accumulation, through the egg stalk, and endogenous accumulation, through intracellular organelles. Management of biological resources will be necessary when oocytes predominate after the active vitellogenic stage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.415-420
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• 2017

In this paper, an algorithm for object counting via a conveyor system using machine vision is suggested. Object counting systems using image processing have been applied in a variety of industries for such purposes as measuring floating populations and traffic volume, etc. The methods of object counting mainly used involve template matching and machine learning for detecting and tracking. However, operational time for these methods should be short for detecting objects on quickly moving conveyor belts. To provide this characteristic, this algorithm for image processing is a region-based method. In this experiment, we counted young abalone shells that are similar in shape, size and color. We applied a characteristic conveyor system that operated in one direction. It obtained information on objects in the region of interest by comparing a second frame that continuously changed according to the information obtained with reference to objects in the first region. Objects were counted if the information between the first and second images matched. This count was exact when young shells were evenly spaced without overlap and missed objects were calculated using size information when objects moved without extra space. The proposed algorithm can be applied for various object counting controls on conveyor systems.

• The Journal of Fisheries Business Administration
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• v.54 no.4
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• pp.19-45
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• 2023

This study explores strategies to expand Korea's top 10 seafood export in the oversea market, with a specific focus on the impact of export concentration. For certain seafood items such as laver, crab, and mackerel, characterized by low export concentration, adopting a focused export expansion strategy is more effective. Conversely, highly concentrated seafood items such as toothfish, cod, pollack, and abalone face high risks in export performance due to their heavy reliance on a small number of key export countries. To ensure export stability, it is advisable to implement a diversified export expansion strategy for these highly concentrated seafood items. In the case of medium-concentration seafood items like tuna, oyster, and flounder, the decision between a concentrated or diversified strategy should be based on their specific export situations. Tailoring strategies to the distinctive market characteristics of each seafood item enables exporters to effectively increase oversea market share, promoting stability and sustained growth in export performance.

• The Korean Journal of Malacology
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• v.31 no.2
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• pp.93-101
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• 2015

The effects of different stocking densities on the growth and survival rate of the 3-year-old pacific abalone, Haliotis dicus hannai were investigated in marine net cage for a year. Stocking densities in net cage ($2.4{\times}1.2m$) was set 15, 30, 45 and 60 percentage (= per)/sq m (square meter, $m^2$) with share to cross-sectional area per shelter. The water temperature during the testing period was $8.2^{\circ}C-22.1^{\circ}C$, and salinity is $33.5{\pm}0.6psu$, and dissolved oxygen is $7.87{\pm}0.86mg/L$. In the shell length (initial size : $71.50{\pm}2.28mm$) growth and shell breadth (initial size : $46.43{\pm}2.28mm$) of the test abalones, the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rates (SGR) of the 15 per/sq m and 30 per/sq m were higher than those of 45 per/sq m and 60 per/sq m density group (P < 0.05). Also in the weight (initial weight : $35.7{\pm}8.1g$), it showed the same results. In survival rates, it were that 15 per/sq m and 30 per/sq m is significantly higher than 45 per/sq m and 60 per/sq m. Therefore, it was that the 15 per/sq m is optimized stocking density in marine net cages about the 3-year-old pacific abalone over 70 mm size. The result shown that total cross-sectional area under the shelter is based on 15 per/sq m ($2.4{\times}2.4m$, 354 number in a net cage) is suitable for fast growth and survival. But if the economy consider, optimized stocking density would be appropriate to accept 30 per/sq m ($2.4{\times}2.4m$, 710 number in a net cage).

• The Korean Journal of Malacology
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• v.16 no.1_2
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• pp.31-34
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• 2000

A series of rearing experiments have been conducted to determine the growth and survival rate in accordance with body size in closed recirculating sea water system. The abalone, Sulculus aquatilis, spat of 10.24${\pm}$0.85 mm, 0.36${\pm}$0.l g and 24.9${\pm}$1.07 mm 2.07${\pm}$0.57 g in shell length and body weight were used in this study Ranges of water temperature and pH during the rearing period of 90 days were 10.0-24.2$^{\circ}C$ and 7.8-8.2, respectively. Dissolved oxygen during the experiment period was 6.13-7.21 ml/l and inorganic nitrate was 0.68-3.72 $\mu\textrm{m}$ in NH$_4$$\^$+/-N, 0.17-7.79 fm in NO$_2$-N and 0.4-11.52 $\mu\textrm{m}$ in NO $_2$-N, Growth in shell length and body weight of the spat in large group and small group at the end of the experiment were 30.80${\pm}$3.14 mm, 17.98${\pm}$2.61 mm and 3.20${\pm}$0.8 g, 0.36${\pm}$0.1 g, and survival rate of spat in large group and small group at the end of the rearing experiment were 96.0% and 90.0% , respectively.

• 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.

• Journal of Aquaculture
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• v.1 no.1
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• pp.103-108
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• 1988

Protoplasts were isolated enzymatically from thalli of Porphyra tenera in relation to its utilization in breeding. As the concentration of the enzymes and incubation period increased, so did the yield of protoplasts. When a 250 mg fresh weight of the thalli was incubated in the $12\%$ abalone digestive enzyme mixture at $22^{\circ}C$ for 3 hours, about $2.5\times10^6$ protoplasts were released. The size of protoplasts ranged between 9$\mu$m and 25$\mu$m, with an average of 14.5$\mu$m.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.460-465
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• 2013

Plate-shaped inorganic particles are coated onto a stainless steel substrate by the electrophoretic deposition of a precursor slurry which includes the inorganic particles of $Al_2O_3$ and polymer resin in mixed solvents to mimic the abalone shell structure, which is a composite of plate-shaped inorganic particles and organic interlayer binding materials with a layered orientation. The process parameters of the electrophoretic deposition include the voltage, coating time, and conductivity of the substrate. In addition, the suspension parameters are the particle size, concentration, viscosity, conductivity, and stability. We prepared an organic-inorganic composite coating with a high inorganic solid content by arraying the plate-shaped $Al_2O_3$ particles and electrophoretic resin via an electrophoretic deposition method. We analyzed the effect of the slurry composition and the electrophoretic deposition process parameters on the physical, mechanical and thermal properties of the coating layer, i.e., the thickness, density, particle orientation, Young's modulus and thermogravimetric analysis results.

• The Korean Journal of Malacology
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• v.32 no.1
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• pp.1-7
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• 2016

The developmental stage of germ cells during oogenesis can be categorized into six stages with histological features: (1) oogonium, (2) previtellogenic oocyte, (3) initial vitellogenic oocyte, (4) early active vitellogenic oocyte, (5) late active vitellogenic oocyte and (6) ripe oocyte. The size of oocyte, nucleus and nucleolus illustrated the increase tendency but size ratio of nucleolus to nucleus was decreased during oogenesis. During oogenesis the stainability in the cytoplasm of oocyte changes from basophilic to eosinophilic in H-E stain. And egg stalk and outer jelly membrane was developed in the oocyte. These histological changes are seemed to be yolk accumulation in the oocyte and preparation process for spawning.

• Journal of the East Asian Society of Dietary Life
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• v.3 no.1
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• pp.12-17
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• 1993

This book is named 'The Ryuk-Jab-Rok' because it was written in the last page of 1820's almanac. This book is written purely in Korean and has not been published yet. This book comprises twenty eight items, among which there are eight items of vegetable preserving method, ten items of Jook preparation methods(a kind of cereal soup), nine items of Pyun-Myun methods(a kind of rice cakes and noodles) and Yak-Bab(a kind of spiced rice). In vegetable preserving method, the eggplant, the cucumber and a songi mushroom were preserved with the drying method., A radish, a sorojangii, and the root of white cabbage were used with the cold temperature preservation. A garlic was dried after salting. The sprouts of DooRub, which were coming in the hot room, were used. In the Jook preparations, there were five animal materials which were lamb, chick, crudian, oyster and abalone. In nine Pyun-Myun methods, Jap-Gua-Sil was illegible because the letters were not clear. Among eight items, the stick rice was used in four cases, the regular rice in two cases. The ground pine nuts, honey and the Chinese date were used most ofter. And the sesame salt and the chestnut were next. The analysis of the terms I this book revealed that 26 items were used for cooking processes. And it also showed us that there were seven kind of cutting procedure and eight kinds of heating procedure. The shapes and size of foods were revealed at only three places in all items. The one-chi(chi ; abut three cm) and three-Ja(Ja ; about thirty cm) which the terms represent the length were revealed twice and once respectively in this book. In the taste description, 'the good', the most common word, was used in seven times, and which was the most frequently introduce case. The measuring unit is hard to revive since the measurements were taken by the container, which were Jong-Ja, Sabal and Tang-gii, then in use. Fifteen kinds of containers and cookers were used for preparing foods. And all of them are now I use.