• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.253-262
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• 2023

This study compared the results of observing the early life history of Gymnogobius urotaenia, which lives in Hwangbocheon Stream, an inflow stream on the east coast, with the differences between fish of the same Gobiidae fishes. In May 2022 and 2023, fertilized eggs and brood stork scattered under rocks were captured twice in Hwangbocheon Stream. The spawning amount was 827~1,540 and the orchid was a elliptical in shape with a size of 3.21×1.07 mm. The stage of ovulation observed in the laboratory was 16 cells, and hatching began after 193 hours. The breeding water temperature range was 18.8~19.3℃. Newly after hatching larvae, the yolk sac with a total length of 3.84~4.33 (average 4.10±0.17, n=30) mm, and the anus was not open. 6 days after hatching of incubation, the total length was 5.32~6.11 (average 5.67±0.25, n=30) mm, absorbing all egg yolk and transitioning to the preflexion larvae, ingesting food, and developing a keynote on the tail fin. 15 days after hatching, the end of the urostyle end was completely bent at 45° with a total length of 7.33~8.52 (average 7.81±0.46, n=30) mm and transitioned to postflexion larvae, and melanophore developed throughout the body. 38 days after hatching, the total length is 22.1~26.1 (23.8±1.36, n=30) mm and the number of fins (6 first dorsal fins, 11 second dorsal fins, and 11 anal fins, 12 ventral fins) is all the number of fin base became integer and transferred to the juvenile. As a result of the study, it was possible to distinguish the melanophore of postflexion larvae of G. urotaenia from other postflexion larvae Gobiidae fish in that they were distributed throughout the body of half the body and tail.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.253-258
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• 1982

The frequent finding of soil contamination by dogs' feces are remarkable, and such soil contamination may be public health problem. Of 608 samples, 30(4.9%) were positive for nematode ova. Ten paint 3% of sail samples from parks and 7.9% from footpaths were found to contain nematode eggs. Of the helminth eggs detected, eggs of Toxocara spp. were the most commonly encountered, and mostly from the soil of footpaths. No eggs were recovered from the soil of school yards; the level of soil contamination was low in public play areas. Egg recovery rate of the soil to dogs' feces collected from footpaths was approximately 1:5. And the larvae demonstrated from the soil in the present study were nematode larvae, mainly recovered from parks.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.67-72
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• 1997

To study the ecological characteristics of the mulberry longicorn beetle, Apriona germari Hope, Mulberry branches with egg-laid scar were regionally collected from ten mulberry fields during the hibernation. It showed that its distribution was highest in Kyunggi province with 3.05% and lowest in Kyungnam province with 0.28%. The number of the egg-laid scar per branch was single with 87.7% of high frequency and its average size was 2.38 L$\times$1.45 W$\times$0.34D cm. The average diameter of scarred branch was 1.7 cm, ranging from 1.3 to 1.9 cm. the shape of egg was long elliptical with width of $2.32\pm$0.33 mm and with length of $6.606.60\pm$0.55 mm. the weight of egg was $16.6\pm$2.94 mg and the color of the just-oviposited egg was milky white, changing into thick brown with time. The weight and length of the just-hatched larva was $16.6\pm$2.4 mg and $6.36\pm$0.66 mm. respectively. Most of the larvae moved downward inside the branch, showing that 94.2% of larvae for outdoor rearing and 87.9% of larvae for indoor rearing moved downward in the branch. As a result, it was found that it hibernated at egg stage with a higher rate than at larval stage by two or three folds in Kyunggi and Kyungbuk province and contrarily at larval stage with higher rate than at egg stage in Chunbuk, Chunnam and Kyungnam provinces. The survival rate for the egg after hibernation was significantly low with 6.6% and contrarily for the larva after hibernation remarkably high with 91.2%. Although the survival rate of the egg in this survey was relatively low, the result indicated that there were two types of hibernation of A. germari in Korea; egg and larval stage.

• Ocean and Polar Research
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• v.39 no.4
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• pp.257-267
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• 2017

Although Pacific mackerel (Scomber japonicus) is an important commercial species in Korea, its recruitment mechanism remains largely unknown. Diel vertical positioning of larvae in the water column, which is affected by their specific gravity and the surrounding water density, may help to provide an understanding on recruitment success through predator avoidance and prey availability. The specific gravity measurement on Pacific mackerel eggs and larvae would seem to be essential information necessary to learn about the transport process from spawning to nursery grounds, and consequently the recruitment success. Eggs were artificially fertilized, and larvae were fed with rotifer when their mouths opened 3-4 days after hatching. We conducted the experiment using a density gradient water column to measure the ontogenetic changes in specific gravity from fertilization to 10 days after hatching. Egg specific gravity was stable during most of the embryonic period, but a sudden increase to $1.0249g\;cm^{-3}$ happened just before hatching. However, the specific gravity of newly hatched larvae was much lighter ($1.0195g\;cm^{-3}$), and specific gravity tended to increase continuously after hatching. Comparison of specific gravity with seawater density reveals that eggs and newly hatched larvae can float in the surface layer of the ocean. For the later period of the experiment, the specific gravity showed a cyclic diel pattern: the highest in the evening while the lowest at dawn. The fullness of larval stomach may be responsible for the observed differences in specific gravity, because stomach fullness was lower (40-60%) at midnight, and higher (80-85%) in evening. The diel pattern of specific gravity might provide clues regarding how larvae match the diel vertical migration of prey organisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.362-367
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• 2015

We followed the development of Pacific herring Clupea pallasii larvae after natural hatching in Korean coastal waters off Dadaepo, where the water temperature was $9^{\circ}C$. Twenty days after hatching, the larvae had (i) reached a total length (TL) of 10.8-12.2 mm, (ii) developed 9-11 dorsal fin rays, and (iii) branched melanophores along the dorsal line of the gut in the anterior half of the body and along the posterior half of the dorsal and ventral line. Thirty days after hatching, the larvae had reached 12.2-13.5 mm TL, and the number of dorsal fin rays had increased to 13-14. Thirty-five days days after hatching, the larvae had reached 14.0-14.7 mm TL, and the posterior ends of their notochords had begun to flex upward. Forty-five days days after hatching, the larvae had (i) reached 15.6-15.9 mm TL, (ii) a complete set of dorsal fin rays (15-16), (iii) 12-13 anal fin rays, and (iv) branched melanophores along the dorsal part of the lateral surfaces of the head behind the caudal terminus. Preflexion, flexion and postflexion stage larvae had TL values of 13.5 mm, 14.0-15.3 mm, and 15.6-15.9 mm, respectively.

• Journal of Apiculture
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• v.33 no.4
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• pp.261-268
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• 2018

Queen honey bees (Apis cerana) can be reared artificially on demand by the use of grafting technique. The technique consists of grafting young worker larvae into queen cell cups and raising in a queenless strong colony. As the age of grafted larvae for queen rearing exhibited several aspects related to quality and reproductive potential of queen, this study were conducted to investigate the influence of age of grafted larva on morphological characteristics and lifespan of queen, and the growth of colony she headed. Our results demonstrated that queens reared from young worker larvae (i.e., less than 1-day old larvae) were significantly larger in size (i.e., body weight and thorax width) than that of queens reared from 2-day old worker larvae. Moreover, queens reared from younger worker larvae initiated egg-laying earlier, stored more spermatozoa in spermatheca and had a longer lifespan compared to queens raised from older worker larvae. We also found a significant positive effect of queen grafting age on the production of worker and drone brood, adult worker population in colonies headed by queens reared from younger larvae. These findings suggested that rearing queens from brood grafted at the earliest possible age could increase the reproductive potential of queen as well as fitness of colony she head.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.67-73
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• 2019

We presented detailed morphological descriptions of the eggs, larvae and juvenile of Acanthaphritis unoorum based on specimens collected with bongo nets from Korean waters during the period May 2017-July 2018. We collected 18 individuals including eggs (n= 4, 0.77-0.85 mm in egg diameter), preflexion larvae (n= 6, 4.11-6.31 mm in standard length, SL), flexion larvae (n= 4, 6.60-7.82 mm SL), postflexion larvae (n= 3, 8.94-13.46 mm SL), and one juvenile (n= 1, 14.67 mm SL). The mitochondrial (mt) DNA 16S rRNA sequences of the eggs, and the cytochrome c oxidase subunit I (COI) sequences of the larvae were identical to those of A. unoorum adults (genetic distances <0.01). The A. unoorum larvae and the juvenile that we collected were morphologically similar to those of Dactylopsaron dimorphicum, but the A. unoorum specimens were readily distinguishable by the presence of lateral melanophores. This is the first record of A. unoorum in Korean waters. We propose a new Korean name for A. unoorum: "O-ri-bu-ri-nuntung-i".

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.267-273
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• 2014

This research has carried out to make a data base of taxonomic research. That Data base explains about spawning behavior, egg development, and morphologic development of variable sabretooth blenny. Fertilized egg was demersal egg which is white and opaque. The number of oil glouble were 10~11, and the size of egg was 0.90~1.43 mm (average rate $1.11{\pm}0.23mm$, n=10). Breeding water temperature was $25.5{\sim}28.5^{\circ}C$ (average rate $27.0^{\circ}C$), and salinity was 32.5~33.5‰ (average rate 33.0‰). After 24 hours from 2 cells, the process of egg development was reached to Blastula stage. Moreover, after 330 hours from 2 cells, nostrils and eyes were formed. Egg membrane was pierced by the head, and the hatch began. After the hatch, postlarvae had 2.59~3.02 mm (average rate $2.81{\pm}0.25mm$, n=5) of whole length, and the mouth and anus were opened. Yolk sac and oil glouble were absorbed. After three days from hatch, prelarvae were 3.02~3.07mm(average rate $3.04{\pm}0.04mm$) of whole length, and caudal fin was grown with round shape. After 13 days from hatch, prelarvae had 3.04~3.20 mm (average rate $3.12{\pm}0.11mm$) of whole length, and they could eat food with upper jaw and bottom jaw.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.69-72
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• 2003

Development and life history of the Korean native firefly, Pyrocoelia rufa, were investigated throughout the indoor rearing. Average size of egg with an oval shape was 1.7 m and the hatchability of egg of P. rufa was approximately 88.5%. The larvae were pupated at the ${5^th}$ instar and the body length of the matured larvae was 27.1 mm. The total periods of larval stage to the end of the 5$^{th}$ instar were approximately 104.7 days. Average pupal period was 10.3 days and average number of eggs oviposited by a female was 87.3 eggs. The body size of female in the pupa and adult was larger than that of male. The wings of female adult were deteriorated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.495-500
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• 1992

The relationship between distribution of eggs and larvae of anchovy, Engraulis japonica, and environmental factors were studied using the data on the ichthyoplankton and zooplankton sampled vertically by net, and water temperature and salinity observed by CTB in the eastern waters of Korea in every two month in 1985. Anchovy eggs and larvae were occurred in June and August. They distributed in the warm water current which was high temperature and salinity in June. Egg and larval distribution area were moved to the offshore in August. It is likely that distribution of anchovy eggs and larval in June significantly correlate with hydroconditions in the eastern waters of Korea.