• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.71-77
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• 2015

Morphological changes in eggs and larvae of spotted knifejaw, Oplegnathus punctatus were observed by cultivation of fertilized eggs to juvenile stage. Fertilized egg was demersal and transparent. The egg has one oil glouble and its size ranged 1.01~1.15 mm ($1.08{\pm}0.10mm$; $mean{\pm}SD$, n=20). Culture chambers were maintained $22.5{\sim}24.5^{\circ}C$ in water temperature and 33.5~34.5ppt in salinity. It took 25 mins from fertilization to the blastoderm stage, 55 mins to 2 cell stage and 20 hrs 50 mins to hatching. Newly hatched yolksac larvae ranged 2.59~3.02 mm ($2.81{\pm}0.25mm$, n=5) in total length, and mouth and anus were not still open. Yolk and oil globule were absorbed 2 days after hatching (DAH). Flexion larvae in 12 DAH ranged 3.02~3.07 mm TL ($3.04{\pm}0.04mm$), and the caudal fin grew to fan-shaped, melanophores appeared on top of digestive canal.

• Journal of Aquaculture
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• v.20 no.4
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• pp.239-247
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• 2007

We studied spawning, hatching and larval growth of Amphiprion melanopus under laboratory conditions. Each time a fish spawned about 440 to 650 eggs. The eggs were hatched 9 days later. Nest colour of the eggs changed from clear yellow orange to greyish violet with processing of embryogenesis. With regard to spawning according to the substrates, the fish prefered red clay pot and ceramic pot to volcanic scoria and live rock. Hatching rate (%) of the eggs on the former substrates was significantly higher than that on the latter. The number of eggs varied with the food stuff supplied to the fish. The fish fed Tetra bits (commercial diet), meat of short necked clams and mussels, and astaxanthin showed significantly higher fecundity with 638 eggs than that fed only Tetra bits (477 eggs) or Tetra bits with meat of shellfish without astaxanthin ($549{\sim}553\;eggs$). Higher temperature ranging from 24 to $30^{\circ}C$ induced shorter incubation period and smaller total length, but higher hatching rate. The optimum salinity and L:D cycle with $60\;{\mu}mol$ photon $m^{-2}s^{-1}$ for hatching were 33 psu and 16:8, respectively. The newly hatched larvae about 4.6 mm in total length grew to 7.5 mm in one week, 18.8 mm in a month and 37.9 mm in 70 days after hatching.

• Journal of Aquaculture
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• v.10 no.4
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• pp.463-472
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• 1997

Floating and hatching rates, size and survival activity index(SAI) of spawned eggs of red spotted grouper, Epinephelus akaara were studied to understand egg qualities during the spawning periods in 1992, 1993 and 1995. The fish spawned from mid-July to mid-August when temperature ranged 23~$28^\circC$. Floating, fertilization and hatching rates were higher in the eggs from early to middle than those from late during the spawning period. SAI ranged 1.8~9.6, and it was closely related to survival rate until mouth operning time (SMOT). Egg diameter decreased gradually with the time of spawning, while diameter of oil globule was constant during the spawning periods. Induced spawnings were carried out with one injection of HCG over 5, 000 IU/kg body weight. Floating, fertilization and hatching rates of the induced spawning eggs were higher than those of untreated ones. Thus, induced spawning method with HCG was recommended for collecting fertilized eggs in bulk. Optimal time for the collection of high quality eggs was supposed to be from early to middle during the spawning periods. Considering that egg qualities were vulnerable within the period, hatchability, incidence of malformed larvae, SMOT and SAI were factors to be considered together to get good quality of eggs.

• Journal of Aquaculture
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• v.12 no.1
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• pp.39-45
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• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.112-117
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• 2014

The spawning behavior, development of eggs and larvae of the blennioid fish, Dictyosoma burgeri were investigated. The blennioid fish were caught at Hwayang-myeon, Yeosu-si, Jeollanam-do from December 2013. The egg was spherical, measuring from 1.31 to 1.47 mm in diameter. The incubation period of the egg extended from 744 hrs at the temperature varying between 14.5 and $16.5^{\circ}C$. The newly hatched larvae were 7.10~7.60 mm(mean $7.34{\pm}0.18mm$) in total length. Two days after hatching, prelarvae was measured 8.43~8.47 mm (mean $8.45{\pm}0.01mm$) in total length. They began to eat rotifer and transformed to postlarvae stage. Six days after hatching, postlarvae was measured 9.06~9.13 mm(mean $9.10{\pm}0.02mm$) in total length.

• Korean Journal of Ichthyology
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• v.2 no.1
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• pp.53-62
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• 1990

Morphological development from egg to juvenile stages of the trident goby, Tridentigertrigonocephalu5 were observed in the laboratory at Pusan, Korea. The ripe eggs were spherical in shape, measuring 0.49-0.62 mm in diameter. The eggs became ellipsoid shape after the insemination and measured about 1.40-1.58 mm on the long axis. Hatching began about 158 hours after insemination at water temperature of $20.5-24^{\circ}C$. The newly hatched larvae were 2.88-3.14 mm in total length(TL), with 27-28(10+ 17-18) myomeres. Many melanophore and guanophores are distributed on eye cups, gas bladder, optic vesicle, intestine and the caudal region. Three days after hatching the yolk and oil-globule was completely absorbed and the larvae attained a total length 3.26-3.62 mm. The larvae swam actively in the aquarium and fed on the rotifer. Ten days after hatching, the larvae averaged 5.20 mm in TL and the caudal notochord flexed at $45^{\circ}$. Twenty days after hatching, the larvae averaged 7.47 mm in TL and rudimental anal, second dorsal, caudal and pectoral fins were formed. The larvae attained 12.05-12.65 mm in TL thirty five days after hatching and are found to transit the bottom-life, and first dorsal and ventral fins are completely formed. The larvae reached the juvenile stage at 45-50 days after hatching and attained 15.85-16.95 mm in TL, and all scales appeared on the body.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.178-185
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• 1997

From November 1996 to April 1997, the rockfish, Sebastiscus marmoratus (Cuvier et Valenciennes) was reared in laboratory, and observed eggs development and morphology of larvae. The eggs of this species are demersal and adhesive, and their diameter were varied within 0.76 to 0.82 mm. The color of yolk is light yellow in early developmental stage, and then turned to orange before hatching out. The yolk contained numerous tiny oil globules. Hatching began about 33 hours and 30 minutes after insemination at $10.0{\sim}14.5^{\circ}C$ of waters. The newly hatched larvae were elongated in shape and 1.62~1.68 mm in total length (TL) with 7~8+16=23~24 myomeres. The larvae absorbed yolk material and oil globule completely in 14 days after hatching and became postlarvae. The spawning season of adult rockfish may be supposed to be from February to March in the southern sea of Korea.

• Journal of Sericultural and Entomological Science
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• v.17 no.1
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• pp.35-39
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• 1975

The acid treatment hatching method has been used practically for about 60 years and a number of investigators have studied about the artificial hatching for silkworm e99s, but the basic theory about the acid treatment hatching is not clarified yet. It is no exaggeration to say that the accidents of non hatching is continued ceaselessly in the silkworm egg by hydrochloric acid treatment. It is believed that the accident is due to the adulterants in HCl lather than inattention of acid treatment. Therefore, the authors mixed hydrochloric acid (analytical grade) with or added it to chemical ingredients which are possible to be included in the process of hydrochloric acid production, and treated it to summer and fall silkworm egg. The metalic adulterants such as iron, mercury, lead and arsenic are appeared not to be worried, but damage of SO$_3$ and free chlorine is seemed to lie considerable. Therefore, before acid treatment for hatching hydrochloric acid was warmed to 50$^{\circ}C$ with shaking to evaporate several injurious gases, by whick the damage due to use of hydrochloric acid for acid treatment hatching is prevented considerably. In conclusion, it is recommended to pretest bioassay with every HCl samples before artificial hatching of silkworm egg.

• Korean Journal of Ichthyology
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• v.8 no.1
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• pp.49-55
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• 1996

The growth of total length(TL), total weight(TW) and somatic weight(SW) of rainbow trout, Oncorhynchus mykiss alevin at yolk absorption period was expressed by the Gompertz growth model as $TLt=2.7e^{-1.24{\cdot}e^{-0.11t}}(r^{2}=0.66)$, $TWt=1.8e^{-2.03{\cdot}e^{-0.11t}}(r^{2}=0.66)$ and $SWt=1.8e^{-5.41{\cdot}e^{-0.13t}}(r^{2}=0.83)$ respectively. Yolk length, yolk height and yolk volume of rainbow trout decreased linearly. The relative growth of total weight-total length, somatic weight-total length, yolk length-total length, yolk height-total length, yolk volume-total length, yolk weight-total length, yolk weight-total weight, yolk weight-yolk height and yolk weight-yolk length at yolk absorption period revealed the pattern of yolk absorption in rainbow trout.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.101-109
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• 2012

The egg development and early life history of Acheilognathus macropterus from Japan which is an exotic bitterling from China were observed under the controlled water temperature, $20.0{\pm}1.0^{\circ}C$. Fertilized eggs are opaque yellow in color and long elliptic globe shaped measuring $2.78{\pm}0.12mm$ in length and $1.44{\pm}0.04mm$ in breadth. The number of egg averaged 151 per an oviposition. The eggs of this species began to hatch about seventy eight hours after insemination and the mean of total length of larvae were 3.8 mm. S form moving of larvae were observed from three days after hatching. The larvae reached at the heterotrophic stage about twenty-five days after hatching. Morphological character and analysis of cytochrome DNA of this species from Japan were relatively similar to Korean but spawned egg shape was different remarkably. Taxonomical research is necessary in the future.