• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.4
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• pp.135-143
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• 1988

To study the abundances of ichthyoplankton in the Nakdong River estuary, ichthyoplankton were sampled with standard net at approximately one month intervals from February, 1987 to January, 1988. Temperature and salinity in the study area showed large seasonal fluctuations due to the inflow of Nakdong River. Among 8 taxa of pelagic eggs occured in the study area, Sillago spp. occupied 37.3% of the total eggs; Coilia spp., 35.8%; Repomucenus spp., 13.7%; Engraulis japonica, 9.4%. These 4 taxa occupied 96.4% of the total eggs. Among 26 taxa of fish larvae, Engraulis japonica was the most abundant species and occupied 36.8% of the total larvae; Gobiidae, 15.3%; Repomucenus spp., 15.0%; Coilia spp., 14.0%; Hexagrammos otakii, 6.8%; Omobranchus elegans, 4.4%. These 6 taxa occupied 92.3% of the total larvae, The densities of pelagic eggs were more than 100 eggs/ 1,000m super(3) from May to October. The densities of larvae were 3.8~221.3 larvae/1,000m super(3). They were relatively high in May, July, and August.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.39-42
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• 1965

The newly hatched silkworm can not come out with the head ahead, but on the contray, it comes out with the tail ahead when it comes out of the chorion, in case the loose-formed eggs are vibrated artificially, at the end of the incubation. So the newly hatched silkworm can not throw off the chorion alone which covers his head. This kind of eggs occurs about 30% when they are vibrated. In case they were raised, they could not grow well and some of them died. The result was quite bad. In conclusion, it would be better to distribute earlier the loose-formed eggs farmers and the loose-formed eggs must not be vibrated at the end of the incubation.

• Journal of Veterinary Clinics
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• v.4 no.2
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• pp.491-498
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• 1987

In an effort to compare parasite egg detection efficiencies, fecal samples from 231 dairy and Korean native cattle in the area of Hongsung - Gun, Kangwon-Do, were examined by the sedimentation and floatation methods. The results obtained were summarized as follows : 1. Detection rates of Fasciola hepatica were 27.2% by the sedimentation method and 61.6% by the floatation method, and those of Paramphistomum spp., were 48.9% and 66.2% respectively. 2. In the Fasciola hepatica, the numbers of cattle contained over a hundred eggs were one by the sedimentation method, but ten by the floatation method. For the Paramphistomum spp., the numbers of cattle contained over a hundred eggs were six by the sedimentation method, but thirty three by the floatation method. Thus, the number of the parasite eggs detected were greater when examined by the floatation method than by the sedimentation method. 3. The numbers of cattle from which eggs were detected only by the sedimentation methods were three and four for Fasciola hepatica and Paramphistomum spp., respectively, while those by the floatation method only were 55 and 44. respectively. 4. Trematodes, nematodes. protozoa and cestodes were floatated by the floatation method using zinc sulfate solution (specific gravity 1.27).

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.365-373
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• 1994

To investigate the effect of EDTA on the in vitro development of parthenogenetic eggs of ICR strain mice, those were cultured in 35mm culture dishes containing NaHCO3-BMOC-3 medium supplemented with 10, 50, 100, or 500$\mu$M of EDTA at 37$^{\circ}C$ for 96hrs. under the atmosphere of 5% CO2 and 95% air. EDTA supplementation of 10, 50, or 100$\mu$M to medium significantly(P<0.01) increase morula and blastocyst formation rate compared with controls in haploid(19.8, 25.9, 39.0% vs. 0.0%). And compared with 10, or 50$\mu$M of EDTA supplementation, significantly(P<0.01) higher morula and blastocyst formation rate resulted from EDTA supplementatin of 100$\mu$M. Both the nuclear number and diameter of blastocysts developed from parthenogenetic eggs were not affected by the morphological types when they were cultured, or the supplementary concentrations of EDTA. The nuclear number of blastocysts developed from haploid, diploid, and immediately cleavaged eggs was 44.8$\pm$1.2, 45.2$\pm$1.5, and 45.4$\pm$1.8, respectively. And the diameter of those eggs ranged 104.4$\pm$1.8, 104.3$\pm$1.2, and 103.8 1.3$\mu$m, respectively.

• Korean journal of applied entomology
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• v.30 no.1
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• pp.37-41
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• 1991

Laboratory experiments were conducted to examine the effects of soil moisture on the survival of the larger black chafer(Holotrichia morosa Waterhouse) eggs and larvae. Survival rates of eggs and 1st, 2nd, and 3rd instar larvae were all above 79% at soil moisture of 15% and 25% in sandy loam and clay loam soil, but decreased considerably at 5% and 35%. At these extreme moistures there seem to be differences in survival rates of eggs and larvae between soil textures. Egg development was delayed as soil moisture approached to the lower limit for survival. Older eggs were tolerant to the high moisture stress(33-36 % , clay loam soil), and duration of the stress affected egg development. Feeding of 3rd instar larvae was obviously suppressed at the higher level of soil moisture.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.2
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• pp.207-213
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• 2011

The diapause of $Telegryllus$ $emma$, the Emma field cricket, was investigated to study the ecological characteristics of the species. Changes in the volume, oxygen consumption, and water content of T. emma eggs were followed from oviposition. An increase in volume, oxygen consumption and water uptake occurred from 7 to 8 days following oviposition. The oxygen consumption of the eggs increased slowly for 7 days following oviposition, but then decreased until 15 days following oviposition. These results showed that a physiological change at diapause initiation affected the volume, water content, and oxygen consumption of the $T.$ $emma$ eggs. An experimental investigation of egg hatching showed that the eggs could be stocked at $10^{\circ}C$ for 40 days with a 14 day pre-period after laying and yield, 62.1% hatchability under these conditions. Maintaining the temperature at approximately $10^{\circ}C$ was favorable for hatching. Another experiment on egg hatching showed that the storage of eggs at $10^{\circ}C$ from 40 to 180 days would ensure satisfactory, hatching capacity.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.283-290
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• 2020

In 2018, 647 thousand tons of eggs were produced and consumed. However, the issue of pesticides used for egg in 2017 made Korean consumers worry about the food safety of eggs, and the volume of egg consumption decreased. The Korean egg industry also has another problem due to an unclear and inefficient marketing structure at the farm level. This marketing situation of eggs at the farm level in Korea needs a large-scale restructuring of the market structure, including introducing an EPC (egg processing center). Especially, the introduction of an EPC has been discussed by government officers and specialists, but the social benefit of an EPC, which will be the driving point for approving an EPC, has not been measured yet. The purpose of this study was to measure the effect of introducing an EPC in Korea. Through an analysis using EDM (equilibrium displacement model), a few findings are presented. First, the introduction of an EPC may increase the transparency of price discovery and decrease the transaction cost. And thus, it results in a higher producer price, lower consumer price, and larger quantity at market equilibrium. Second, an EPC will improve the level of food safety of eggs, which can increase the satisfaction of domestic producers and consumers. Third, the introduction of an EPC may create new consumption of eggs. Based on these three effects, the new social benefits in monetary terms from the introduction of an EPC in Korea could be 23.9 - 35.2 billion won.

• Parasites, Hosts and Diseases
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• v.49 no.3
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• pp.323-326
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• 2011

While the presence of pinworm eggs in archaeological samples has been reported by many researchers in the New World, those have been detected very scarcely in the Old World, especially in East Asian countries. In fact, many parasite species were recovered from the archeological remains in Korea, eggs of Enterobius vermicularis had not been found. Recently, a female mummy buried in the 17th century was discovered in the Joseon tomb from Dangjin-gun, Chungcheongnam-do, Korea. After rehydration process for 12 days, investigations were carried on the luminal surface of the colon. From them, 3 eggs of E. vermicularis were recovered. They were elliptical, transparent with a thin egg shell, $50.3{\pm}5.2\;{\mu}m$ (length) and $28.2{\pm}3.9\;{\mu}m$ (width) in size. This is the first discovery of E. vermicularis eggs in East Asia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.146-153
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• 2022

The vertical distribution and abundance of icthyoplankton in the southern waters of Jeju Island during June 2020 were investigated. Fish eggs and larvae were identified using the mitochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) and the 16S rRNA gene. During this period, fish eggs of 23 taxa belonging to 21 families and larvae of 27 taxa belonging to 25 families were collected. Fish eggs were located mostly from the surface to 30 m depth of the water column. Larvae were located from the surface to 80 m depth of the water column. Vertical distributions of fish eggs and larvae were influenced by oceanography conditions such as temperature, salinity, and thermocline depth. No discernible difference in mean thermocline depth was observed between day and night.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.243-251
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• 2018

Eggs, immature eggs, and pupae of 8 different insects (Halyomopha halys, Riptortus pedestris, Lymantria dispar, Antheraea yamamai, Verlarifictorus spp, Antheraea pernyi, and Musca domestica) including Lycorma delicatura were used to select the alternative host for laboratory mass rearing of A. orientalis. Except L. delicatula's eggs and immature eggs of A. pernyi, other 7 tested insects were not parasitized by A. orientalis. A. pernyi was reared with oak tree leaves and its cocoons were harvested on mid-July and early October. On 4 or 5 days after emergence, only female adults showing swollen abdomen were collected and stored at $1{\sim}5^{\circ}C$. We could get 150~200 eggs per one female by dissecting the female's abdomen. For examining the possibility for laboratory mass rearing of A. orientalis with A. pernyi's immature eggs, developmental periods from egg to pupa between the two different hosts were compared. Developmental periods were 36.1 days on immature eggs of A. pernyi and 36.8 days on an original host's eggs, respectively. The number of parasitized eggs by A. orientalis' female for 24 h was 3.4 on immature eggs of A. pernyi and 4.2 on an original host's eggs, respectively. However, there were no significant statistical differences in developmental period and parasitization between the two hosts. By supplying honeyed water to newly emerged female parasitoids, it was able to maximize their longevities up to 64.3 days after emergence. Therefore, our results support potential for laboratory mass-rearing of A. orientalis using A. pernyi's immature eggs as an alternative host.