• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.477-483
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• 1985

This paper describes seasonal changes of total length, hepatosomatic index (HSI), fatness, egg-diameter composition, and fecundity of the longchin goby Chasmichthys dolichognathus(HILGENDORF). The specimens used were captured in the tide pool of Tongbaekseom, Pusan, Korea from February 1983 to January 1984. The age of longchin goby, tested by size frequency, was believed to be usually one year which grows to 8.0 cm in total length. The annual variations of HSI reached the maximum in the early spring when the gonad was actively growing and decreased during the spawning season from April to July. The coefficients of fatness were represented low values for the spawning periods. Frequency distribution of the egg diameter of mature ovary has three modes: one is the evident mode of the ripe eggs group, and the other two are modes of maturing and immature eggs groups. And an individual is considered as spawns one in the spawning season. Relationships between the fish size in total length (TL cm) and the number of ovarian eggs(F), the fish weight (BW g) and the number of ovarian eggs are indicated by the exponential equation respectively : F=42.585 $TL^{1.608}$, F= 524.589 $BW^{0.475}$.

• The Korean Journal of Malacology
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• v.31 no.1
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• pp.21-26
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• 2015

This study histologically describes the gonadal development and reproductive cycle of the abalone, Haliotis discus discus inhabiting Jeju Island of Korea. Gonads displayed histologically definitive seasonal changes. The gonad index (GI) of both females and males was the highest (3.2 and 3.3) in September and was the lowest (1.7 and 1.4) in January and February. Egg diameter increase from early stage in March and reach about $180{\mu}m$ to ripe stage in August. The condition index (CI) was highest in July and lowest in May. The pattern of changes in the GI, egg diameter and CI were similar to the pattern of seasonal changes in gonadal tissues. The female ratio (F/F + M) was 59% (n = 182:127). The reproductive cycle was divided into an inactive stage (January-February), early active stage (March-April), late active stage (May-July), ripe stage (August-October) and spent and degenerative stage (November-January). The main spawning period of H. discus discus was August to October at Jeju Island in 2014.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.24-29
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• 2017

This study was conducted to identify nesting habits and breeding biology of barn swallow in Gwangju, Korea, for the breeding season 2012 to 2014. All nests were attached to vertical walls and roofs of buildings and situated at mean height $2.9{\pm}0.3m$ above ground with nest diameter $18.2{\pm}3.2cm$, nest depth $9.8{\pm}3.1cm$, nest cup diameter $11.2{\pm}1.5cm$ and nest cup depth $3.27{\pm}0.80cm$. Nests were attached to cemented walls (44.9%), wooden materials (23.1%), bricks (21.8%) and lighting (6.4%). The average clutch size was 4.5 and ranged 2~5. Mean egg length was $18.23{\pm}0.73mm$, breadth $13.11{\pm}0.25mm$, volume $1.60{\pm}0.11cm^3$, shape index $1.39{\pm}0.05$ and weight $1.69{\pm}0.15g$. Hatching and fledgling success rate were 89.1% and 84.5%. Main causes for reproductive failures were unhatched eggs, predation, nest destruction and desertion. These results are expected to be widely used as data for habitat preservation and species management of barn swallows.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.10-19
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• 2023

This study aimed to examine the early life history of Trident goby (Tridentiger brevispinis) by observing their egg development and juvenile fish morphology. The average size of mature eggs was 1.13~1.41 (1.30±0.07) mm (n=30), and 0.70~0.86 (0.79±0.04) mm (n=30) in long diameter and short diameter, respectively. The incubation period at 24±1℃ ranged from 167~228 h. The newly hatched larvae measured 2.31~2.78 (2.51±0.18) mm (n=30) in total length (TL), and their mouth and anus were not yet open. At 3 days after hatching, the preflexion larvae reached 2.84~3.10 (2.98±0.10) mm in TL, where in their yolk absorption was complete and their mouths began to open. At 19 days after hatching, the larvae reached the flexion stage, measuring 4.02~4.62 (4.36±0.19) mm in TL. The tip of their notochord was bent upward. At 30 days post-hatching, the larvae reached the postflexion stage, measuring between 5.04~6.36 (5.76±0.51) mm in TL, with the tip of the caudal fin bent at 45°. After 54 days, the larvae had reached the juvenile stage, measuring between 7.43~9.84 (8.48±0.90) mm in TL, and were differentiated by their constant number of fins (6 first dorsal, 12 second dorsal, 11 anal, and 10 ventral fins). This study found that T. brevispinis had larger fertilized eggs and a greater number of myotomes in hatching larva than similar species. Additionally, the distribution of melanophores in T. brevispinis was distinct from that in other similar species, making it easy to distinguish them morphologically.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.73-82
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• 2005

This study was conducted, based on the field survey and laboratory observations, to elucidate egg developmental processes and their characteristics of the Korean slender gudgeon, Squalidus gracilis majimae. For the experiments, the mature adults were collected at the Woongcheon-Cheon Stream and Boreung Reservoir located in Boreung City, Chungnam Province and eggs were obtained from the natural spawning area. Morphological characteristics of the egg and embryonic development were summarized as follows: The shape of the fertilized egg was spherical, adhesive and transparent. The fertilized egg was 2.9${\pm}$0.3 mm (n = 30) in mean diameter under water temperature of $26{\pm}1.5^{\circ}C$, light white in color and had no oil droplets. After 20 minutes from the time of fertilization, a blastodisc was formed and divided into two cells at 48 minutes after fertilization. The blastular stage occurred at 5 hours 40 minutes after fertilization and the gastrular stage was detected at 8 hours 41 minutes after fertilization. The beginning of embryo formation was observed at 12 hours 58 minutes after fertilization and optic vesicles and 9 somites were discovered at 17 hours 05 minutes after fertilization. Differentiation of brains and embryo wiggling were observed at 37 hours 27 minutes after fertilization. Heart beating and the formation of melanophores in optic vesicles were detected at 44 hours 46 minutes after fertilization. The formation of pectoral fins and melanophores in the body were discovered at 50 hours 36 minutes after fertilization. Hatching occurred at 57 hours 49 minutes after fertilization. The newly hatched larvae were 3.3${\pm}$0.2 mm (n = 120) in total length. We believe that these results may contribute the species and population conservations under the situation of accelerated water pollution and the decreases of its diversity.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.63-70
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• 2012

This study was conducted to investigated the distribution, ecological character and life cycle of Black Soldier Fly(BSF), Hermetia illucens, to determine effects of BSF on composing ability to the livestock feces. The distribution of BSF was defined in all parts of the country in Korea. Its main habitat was found to be areas near cattle sheds, feces sheds, living waste dump grounds, and food waste dump grounds. Excellent species of the bio-conversion using the livestock feces were selected out of two kinds of solider flies(Hermetia illucens and Ptecticus tenebrifer). And effects of BSF on composing ability to the livestock feces were pig feces 0.5 g, cattle feces 0.43 g and chicken feces 0.3 g per a larvae of BSF. In the examination of the ability of BSF to decompose food waste, volume of the livestock feces decreased by weight pig feces 77, cattle feces 83.62 and chicken feces 80%. Observed characteristics of BSF larvae and pupae stage were by developmental stage may be summarized as follows: size and length of larvae and pupae of BSF were higher than in pig feces and mixed sawdust treatments. In order to develop artificial indoor rearing techniques, The pupation and emergence rate were not visible the difference but important factor of the mating and egg-laying was a sun light. And it was visible the difference in mating ratio. Mating rate of H. illucens by seasonal change was the highest from May to July. Mating mostly occurred between 10 : 00 and 12 : 00 during which light intensity is high. As the egg-laying medium for artificial egg collection, calf feed and food waste were most effective. The ratio of egg-laying medium is waste food : sawdust(1 : 1) in volume. For egg-laying materials, flower foam and wood with holes were used; holes sized 3 ~ 5 mm in diameter, 7 ~ 10 mm in depth were most preferred for egg-laying.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.86-93
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• 1999

Artificial fertilization of flounder, Limanda herzensteini caught at Pohang brook was performed in April 13, 1995 and hatched larvae were reared for 25 days to describe the development of eggs and the morphogenesis of larvae. The fertilized egg was buoyant, colorless and spherical in shape, measuring 0.86~0.96 mm in diameter (mean: 0.90 mm), The egg has no oil globule, and its perivitelline space was narrow. Hatching in the indoor tank with $16.0^{\circ}C$ in mean water temperature started from the 64 hours after fertilization. The newly hatched larva, measuring about 2.80 mm in total length, had 10~11+25~27=35~38 myomeres. The anus is open at about the anterior point of the body. The 3 to 4 days old larva was 3.90 mm in total length. In this larva the eyes were black and the mouth was open. The yolk was consumed in 8 to 9 days. In 20 to 22 days after hatching, the larvae grew 6.1 mm in total length. The eyes were located symmetry on both sides of head.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.86-94
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• 2015

Egg development and early life history of the endangered species, Microphysogobio rapidus was investigated to get a basic information for biological characteristics and recovery strategy. Eggs were obtained from females by injecting Ovaprim (0.5 mL/kg) and artificially fertilized by dry method in the laboratory. The mature eggs were slightly adhesive and separated with light bluish green and $0.63{\pm}0.02mm$ (n=20) in diameter. Number of eggs in the ovaries were $3,827{\pm}1,225$ (2,850 ~ 5,916). The hatching occurred at 72 hours after fertilization under water temperature of $21{\pm}1^{\circ}C$. The newly-hatched larvae were $2.79{\pm}0.04mm$ (n=10) in total length. At 5 days after hatching, they were average $4.10{\pm}0.07mm$ (n=10) in TL and their yolk sacs were completely absorbed. 30 days after hatching, they became to juvenile stage and reached $9.74{\pm}0.24mm$ (n=10) in TL. At 100 days after hatching, the band patterns and external form were similar to those of adults, average $27.00{\pm}1.94mm$ (n=10) in TL.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.95-103
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• 2015

Egg development and early life history of the Korean spine loach, Cobitis tetralineata, were investigated in the present study. Adult fish were sampled using spoon nets at the Seomjin River in Jeongsan-ri, Bokheong-myeon, Sunchang-gun, Jeollanbuk-do, Korea, July 2013. Eggs were obtained after injecting Ovarprim into females. Eggs were then artificially fertilized using the Dry method in the laboratory. Mature eggs were slightly adhesive and transparent with grey coloring, and measured $1.04{\pm}0.03mm$ ($mean{\pm}SD$) in diameter. Hatching of the embryo occurred approximately 56 hours after fertilization at $25^{\circ}C$ of water temperature, and the average size of newly hatched larvae was about $4.6{\pm}0.11mm$ in total length. At fifth day after hatching, the larval full length reached $6.8{\pm}0.28mm$ on average and their yolk sac had been completely absorbed. At 17th day after hatching, larva entered the juvenile stage and reached $9.8{\pm}0.50mm$ in total length. At 100th day after hatching, the formation of Gambetta's zone of four line was complete and juveniles were similar in general appearance to adults, and they averaged $34.7{\pm}5.77mm$ in total length.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.167-173
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• 2011

This study was performed to describe the effect of water temperature, salinity and density on the eggs development of the hard clam, Meretrix petechialis. Eggs of Meretrix petechialis were turned out to be demersal isolated eggs of $82.3-86.1{\mu}m$ in an average diameter after spawning. The hatching rate of D-shaped larvae by elapsed time after spawning was the highest in fertilization immediately after spawning and distinguished decrease from 1 hour of spawning. The optimum water temperature for development of D-shaped larvae from fertilization was ranged between $25^{\circ}C$ to $27^{\circ}C$. However, D-shaped larvae was not developed at $33^{\circ}C$ of water temperature. The required time from fertilization to D-shaped larvae were 37.3 hours in $20^{\circ}C$, 20.8 hours in $25^{\circ}C$, and 15.3 hours in $30^{\circ}C$. Biological minimum temperature for the egg development was estimated to be $12.4^{\circ}C$ in average. The range of salinity for the development of eggs were 20.0-37.5 psu, optimum range was estimated to be 27.5-32.5 psu.