• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.435-442
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• 1995

The abalone shell (Haliotis) is one of the most important resources for the coastal fisheries and it is popular as an aquacultural species. Proper cultivating grounds for mid-term nursery of abalone spats are required before releasing them. It is difficult for us to find good enough aquacultural grounds to rear abalone spats to 20"30mm of shell length. Therefore, we need to study a practical and effective new type of aquacultural device for the nursing of abalone spats by using open sea areas. We can find this kind of studies from 'Marine aya No. 1' of Japan, Though they focused on the easy operation, safe working and low operating cost, it involves so much initial cost that it is difficult for us to justify such expenditure. However, with a modified small buoy system, this submersible facility needs only a horizontal frame to fulfill its essential function and the vortical part can be removed. The working boat equipped with a pump can operate this facility to keep it submerged or floated. This paper deals with the possibility of this submersible fishery facility for the mid term nursing of abalone spats in the open sea. A small version of this system to ensure low initial cost is suggested and wave and current forces were calculated for the estimation of the weight of the mooring anchor.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.187-188
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• 1995

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.353-361
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• 2014

In order to investigate the effects of copper alloy on abalone physiology, we studied survival rate, respiration, excretion rate, and heavy metal accumulation in each organ of adults and spats. The survival rate of spats and adults showed 27-60% and 63-83% respectively, higher survival rate in adults. In particular, 100% of copper panel led to lowest survival rate and there was no sharp distinction according to copper alloy composition. The respiration rate and excretion rate of ammonia nitrogen was $1.81mgO_2/g$ D.W./h and 0.43 mg $NH_4-N/g$ D.W./h respectively at 100% of copper panel. In other words, there was a high significant difference at the level, but no significant difference at other test levels (P < 0.05). The atomic ratio (0: N) hit the lowest at the 100% of copper panel showing 3.79 and no significant differences were seen among other test groups with 6.57-7.18 of a very low range. This means that the species might have undergone nutritional stress. In case of copper accumulation, the 100% copper panel group showed the highest level in hepatopancreas and muscle showing 6.91 mg/kg and 1.60 mg/kg respectively but the rest of groups showed similar levels. Zinc accumulation raised at Cu-Zn alloy panel had high significance showing 18.50 mg/kg and 1.10 mg/kg in hepatopancreas and muscle respectively (P < 0.05). To sum up, a cage net made of 100% pure copper is expected to have a negative effect on abalone in light of survival rate, heavy metal accumulation, and atomic ratio (0: N). Moreover, given that the substratum used for the high adhesive species and nutritious stress that is represented through the atomic ratio need to be considered, the copper alloy net is thought not to be suitable for abalone aquaculture.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.189-195
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• 2013

Experiments for net cage culture at sea were conducted in each $2.4{\times}2.4$ m in area and took the samples from four different densities: 150, 300, 450 and 600 per cross-sectional area ($m^2$) of shelter. The same stocking densities applied to indoor tank culture to investigate the growth and survival rate. The size of juvenile abalone sample was $36.14{\pm}2.28$ mm for net cage culture and $38.62{\pm}3.22$ mm or indoor tank. Feed such as raw brown sea mustard, raw kelp and dried kelp was sufficiently provided to the abalone. In net cage culture experiment, the growth of the spat of juvenile abalone was the fastest $60.53{\pm}5.75$ mm in the 150 abalone cage per square meter ($m^2$), followed by the 300 abalone cage at $54.01{\pm}5.17$ mm, 450 abalone cage at $51.48{\pm}5.37$ mm and 600 abalone cage at $51.09{\pm}4.96$ mm in order. In the meantime, in the indoor tank experiment, the 150 abalone indoor tank was the fastest $47.50{\pm}6.31$ mm per square meter, followed by the 300 abalone tank at $45.92{\pm}5.23$ mm, the 450 abalone tank at $44.24{\pm}5.59$ mm and the 600 abalone tank at $43.62{\pm}4.44$ mm in order. The survival rate was more than 97.9% in all the experiments, not showing a significant difference.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.225-232
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• 2013

This study looked into recovery rate and histological changes in the gills of juvenile abalone Haliotis discus hannai by exposure time (3, 6, 12, 24 and 48 h) of different water temperatures (15, 20 and $25^{\circ}C$) and salinities (30, 25, 20 and 15 psu) to understand reasons for the death of abalone exposed by low salinity water. In each water temperature, abalone spats that were exposed to low salinity water (less than 20 psu) for over 6 hours showed decrease in survival rate during recovery and those were exposed at the salinity of 15 psu for more than 24 hours all died. Histological observation showed expansion or damage of gills of the species which were exposed at less than 20 psu for over 6 hours. In case of abalones exposed at the salinity of 15 psu for over 24 hours, most gill tissues were destroyed. This result was glaringly obvious at a higher water temperature, lower salinity and longer exposure time. Accordingly, suffocation caused by damage of gills considered one of direct causes of the death.