• Journal of Aquaculture
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• v.13 no.2
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• pp.119-128
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• 2000

Exposure to air and increased temperature induced successful spawning in Mytilus edulis, M. coruscus Crassostrea gigas and Pinctata fucata martensii. Developmental durations required for an egg to attain D-shaped larva and the D-shaped larva to reach pediveliger stage were estimated in these bivalves. Size of fertilized eggs was the largest (70.3 ${\mu}m$) in M. coruscus and the smallest (45.3 ${\mu}m$) in P. fucata martensii. At 17$^{\circ}C$, M. edulis and M. coruscus attained D-shaped larval stage within 48 hours after fertilization but those of C. gigas and B. fucata martensiii within 24 and 22 hours at 21 and 26$^{\circ}C$, respectively. The development duration required for a D-shaped larva to attain pediveliger stage was the longest (27 days) in M. coruscus and ranged between 20 and 22 days for the others. The shell length of the pediveliger was the longest (274.9 ${\mu}m$) in C. gigas and smallest (190.9 ${\mu}m$) in P. fucata martensii Length and height of larval shell was highly correlated with each other in all the 4 species. The shell height of C. gigas was more than the shell length beyond the size of 100 ${\mu}m$ shell length. However, shell length of the others was always longer than shell height at the larval stage.

• The Korean Journal of Malacology
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• v.26 no.2
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• pp.151-156
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• 2010

For industrialization of the hard clams, Meretrix petechiails (Lamarck), spawning was induced per spawning induction technique in the artificial maturation group administered of parent maturation control and the natural maturation group of which parents were transported for artificial spawning per time period. Then, fertilization rates, hatching rates and D-shaped larva development rates were investigated. In addition, growth and survival rates of larvae were investigated per larva breeding technique. The results of spawning induction by exposure in the artificial maturation group indicated that response rates were relatively higher at 23% and 32% respectively at the 4th hour and the 8th hour of exposure. In terms of water temperature increase, responses began only when the temperature reached $28^{\circ}C$ or higher. In the experiment group administered with both exposure and water temperature increase techniques, response rate was found to be 45% or higher at the 4th hour of exposure and the temperature of $28^{\circ}C$. At the temperatures of 29, 30 and $31^{\circ}C$, significant differences were not observed. Therefore, it was indicated that the response rates of parent hard clams were higher toward water temperature increase than exposure time. As for spawning induction per time period of the transported parent group, response rate and D-shaped larva development rate were the highest at 67.6% and 96% respectively on August 6, 2009. In terms of water temperatures during larva breeding experiment, growth was faster as water temperature was higher. In addition, growth and survival rates were relatively higher at the salinity of 25. In terms of stocking density, growth and survival rates were relatively higher at 5 inds./mL.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.567-573
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• 1998

Cold storage of concentrated food phytoplanktons is a useful technique in supplying food organisms for artificial shellfish seed. One month after preservation at $4^{\circ}C$, we have measured survival rate of the concentrated food phytoplanktons, Pavlova lutheli, Isochrysis galbana, Isochrysis aff, galbana and Chaetoceros calcitrans. Thereafter we determined survival rate of oyster lavae fed fresh and concentrated diets and fatty acid compositions of the fresh and concentrated food phytoplanktons. Survival rate of concentrated planktons ranged from $23\%$ to $31\%$ after one month at $4^{\circ}C$. The survival rate of oyster larvae fed cold stored food appeared generally higher than those fed fresh harvested food. Especially, the highest survival rate were found in the larvae fed cold stored concentrated I. aff. galbana. EPA and DHA increased after cold storage and the highest level of DHA was detected in I. aff. galbana. As DHA can role as an important factor in determing nutritional value, it would be better to use concentrated I aff, gaibana kept in cold refrigerator for oyster seed production.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2005.07a
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• pp.39-39
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• 2005

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2005.07a
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• pp.41-41
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• 2005

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.63-69
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• 2020

This study investigated spawning characteristics of Hangang bitterling, Rhodeus pseudosericeus inside the host mussel, Unio douglasiae sinuolatus at the Heukcheon Stream in Korea from April to June 2017. 327 mussels were collected, among them, 34 (14.1%) were spawned mussels of R. pseudosericeus with glochidia. The mean number of R. pseudosericeus embryos with or without glochidia by the mussel gill position was 5.0±3.58 (range, 1~8) vs. 2.8±2.13 (1~9) in the left outer demibranch, 1.5±0.96 (1~3) vs. 1.7±0.82 (1~3) in the left inner demibranch, 1.4±0.51 (1~2) vs. 2.1±1.85 (1~6) in the right inner demibranch, and 6.4±4.82 (1~20) vs. 3.0±1.86 (1~6) in the right outer demibranch. The frequency of R. pseudosericeus embryos with or without glochidia by the mussel gill position was 82.6% vs. 73.4% in the left outer demibranch, 17.4% vs. 9.4% in the left inner demibranch, 26.1% vs. 15.6% in the right inner demibranch, and 58.7% vs. 67.2% in the right outer demibranch. The mean number of R. pseudosericeus embryos with or without glochidia was 8.5±6.43 (1~23) vs. 4.5±3.38 (1~14). The number and frequency of R. pseudosericeus embryos were higher in the mussel with glochidia and the outer demibranchs than those without glochidia and with inner demibranchs.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.303-309
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• 2014

The development of Japanese geoduck, Panopea japonica, grown under culture conditions, has been examined through the morphological characteristics in fertilized egg, larvae and juvenile. Gametes were stripped from ripe broodstock and placed into two separate containers. Eggs were washed through a $40{\mu}m$ sieve and fertilized with dilute sperm solution. Developing larvae were maintained at $19{\pm}1^{\circ}C$. Fertilized eggs with $81.6{\mu}m$ diameter developed to trochophores within 14 h and to D-stage larvae ($116{\mu}m$ shell length) within 27 h. Larvae were spontaneously settled at shell length of $311{\mu}m$ after 20 days. The hatching from fertilized eggs and larval rearing were normally available in $18.5-21.5^{\circ}C$, and the growth was good in a cashmilon substrate, as well as sand. After rearing of day 108 from metamorphosis, the shell length of juvenile P. japonica reached 13 mm, and growth rate of shell length of the juvenile was $117.5{\mu}m/d$.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.19-24
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• 2003

Artificial spawning, larval and spat developments of the bay scallop, Argopecten irradians, which was transplanted from China on 16 August 1996, were investigated monthly until August 1997 in the Deukyang Bay, Jangheung-gun, Jeollanam-do, Korea. Sufficient amount of cultured microalgae supplemented seawater were supplied as food (6 kinds of phytoplankton) for fully grown adult individuals at 17.1-23.2$^{\circ}C$ for 44 days. A total of 45,320,000 eggs were spawned by way of 2 times of artificial spawning inductions such as exposure stimulus to the air and thermal shock (with water temperature) on 29 January and 31 January in 1997. Artificially fertilized eggs were developed to D-shaped larvae (77.5 ${\times}\;63.8\;{\mu}m)$ and metamorphosed to larvae (191.8 ${\times}\;181.2\;{\mu}m)$ 181.2 m) in the attached larval stage on the collectors. A total of 110,000 spats (average 3.04 mm in shell length) were produced at 22.8-26.3$^{\circ}C$ and 31.0-34.4 psu in the indoor rearing tank from 14 February through 7 May in 1997. In case of Argopecten irradians, if the attached larvae in the attachment stage are detached from the collector, they could not live. Accordingly, it is assumed that survival (%) of the attached larvae of A. irridians showed very low because of weak power attached to the collector due to the small number of the byssuses of the attached larva, not the short attachment period by the byssus as seen in other scallops such as Argopecten balloti.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.91-96
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• 2013

Although the method of seedling production of Haliotis discus hannai is well known, the optimum benthic diatom species as a live food at early larval stage are not fully developed. In this study three Pennales diatom species, Caloneis schroederi, Rhaphoneis sp., and Cocconeis californica were examined on settlement, metamorphosis, survival, and growth of Haliotis discus hannai larvae. The larvae fed Raphoneis sp. or C. californica showed high settlement rate with 80-82% within 48 hrs, which was significantly higher than those fed C. schroederi or mixed diets with three diatom species. The larvae fed the former microalgal species also showed higher metamorphosis rate with 32-34% than the latter species with 10-12% within 4 days. With regard to survival and growth of the larvae, single diet with Rhaphoneis sp. or C. californica had better dietary value than the mixed diets for the early larvae of H. discus hannai.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.52-62
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• 1974

The fresh water prawn, Macrobrachium rosenbergi (De Maan) is a very common species in Info-pacific region inhabiting both fresh and brackish waters in low land areas, and especially abundant in the lower reaches of most rivers which are influenced by seawater, It is one of the largest and commercial species of genus Macrobrachium. As a place of the researches to clear the possibilities of transplantation and propagation of this species in the Far East region the larval development, growth, optimum temperature and metamorphose rate up to first post larvae in aquaruim are cleared under the conditions of salinity $6.58-7.05\%_{\circ}$ Cl, pH 8.0-8.2, the rate of flow 0.3 liter per minute and illumination 3000 lux. Temperature ranged from 27.5 to $28.7^{\circ}C$ during the period of earlier larval development. For the study oil the relationship between temperature and metamorphose rate from zoea to first post larvae, the temperatures in experimental tank were $22.2^{\circ}C\pm1$, $26.1^{\circ}C\pm0.85$, $28.1^{\circ}C\pm0.34$, $30.4^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.38$ and $36.8^{\circ}C\pm0.26$. During the work, food used for the larvae was Artemia salina nauplius in the filter-circulation aquariums. This species metamorphosed to the first post-larvae through eleven zoea stages, and the characters of each larval stage are described and optimum temperature for metamorphosis rate and survivals to the first post larvae is $28.1^{\circ}C\pm0.34$.