• Korean Journal of Ichthyology
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• v.36 no.3
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• pp.209-219
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• 2024

A survey was conducted in 2011 to investigate the reproductive ecology and spawning behavior of the natural monumental and endangered species, Cobitis choii. C. choii exhibits sexual dimorphism with the development of lamina circularis on the second pectoral fin ray in males at one year old, facilitating easy differentiation between males and females. A total of 1,288 females and 881 males were collected from January to December, resulting in a sex ratio of 1 : 0.68. The spawning season was estimated to be from late June to early July (spawning peak from late June, with water temperatures ranging from 22 to 25℃), coinciding with a sharp decrease in the condition index. Gonadal maturity was observed with maturity indices of 17.5±2.11% for females and 2.9±0.46% for males, with fecundity of 2,444±838 eggs and egg size of 0.75±0.05 mm. Spawning behavior was induced by hormone injection (Human Chorionic Gonadotropin, HCG) in laboratory conditions. Experimental results revealed that males and females paired in a 1 : 1 ratio before spawning. Males pressed the abdomen of females using their lamina circularis to induce spawning, followed by immediate fertilization. Spawning behavior was repeated 15 to 25 (average 20) times per pair of males and females, and 80 to 120 eggs were spawned per time, and the total amount of spawned eggs were 2,500±250 on average.

• Korean Journal of Environment and Ecology
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• v.26 no.6
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• pp.876-883
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• 2012

In order to analyze the meteorological factors influencing breeding activities of the Kaloula borealis, spawning sites which are located in Daejung-Eub, Jeju Island were investigated for 4 years from 2008 to 2011. The factors for analysis were rainfall, humidity, temperature, barometric pressure and wind speed. Comparative analysis were done on the spawning activities on rainy days. The analysis shows that the main factors influencing breeding activities of the Kaloula borealis are rainfall, humidity, and barometric pressure. The most influencing factor among them is rainfall. According to the analysis, the Kaloula borealis participate in spawning activities when it rains hard and humidity and barometric pressure also have influence on their spawning activities to a certain degree. As for temperature, the breeding season is summer so it meets one of the conditions for breeding activities. As a result, like the previous studies on other anurans in temperate regions, rainfall and temperature have a great impact on breeding activities of the Kaloula borealis.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.77-85
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• 2015

Siniperca scherzeri is major target species for restocking and restoration project as it is one of the economic species in South Korea. In this study, to investigate their ecological characteristics movement pattern and habitat characteristic of S. scherzeri were analyzed using radio telemetry. Three specimens released during spawning season, moved more than 10 km toward upstream from the release site. Whereas the remains released after spawning season, settled within 400 m of their release site except two specimens (Ss 11, 3.2 km; Ss, 15, 1.4 km). One of possible reason of upstream movement during spawning season is reproduction. The conditions of their settlement area is similar with reference conditions of their spawning ground. S. scherzeri were mainly detected near the edge of the water, and it may related with the facts that rocks are mainly located at the edge of the water and S. scherzeri prefers rocks for their shelter. AMD (Accumulated movement distance) positively related with body weight and condition factor K, but no significant relationship was identified with gender and total length. Daily movement boundary of S. scherzeri was $214.94m^2{\sim}3,257.19m^2$, and their movement was restricted near the edge of the water. The results of this study could be useful to restocking and restoration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.485-491
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• 2004

Spawning induction, egg development and larval growth of ark shell (Tegillarca granosa) (L.) were investigated. The most effective method of spawning induction was steady temperature increasing from$4^{\circ}C\;to\;28^{\circ}C$ with irradiation of sea water by UV after T. granosa was exposed to air at $4^{\circ}C$ Optimum condition for larval roaring was under the 32.4 psu and two temperature $regimes:\;28{\pm}1^{\circ}C\;and \;25{\pm}1^{\circ}C$. Fertilized eggs was demersal isolated eggs, and egg diameter was $60{\mu}$. D-shaped larvae appear about 20 hr after hatching with $94.1{\mu}$ in shell length and $86.7{\mu}$ in shell height. Ten days were required from hatching to umbo larva stage, of a mean shell length $125.2{\mu}$. On 25th day, the larva grew to $450{\mu}$ in shell length and began to settle on the bottom. Effect of temperature between $25^{\circ}C$ (control group) and $28^{\circ}C$ on larval growth was not different. Survival rate of larvae settled on the bottom was about $19{\%}$ in both temperatures conditions $(25^{\circ}C\;and\;28^{\circ}C)$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.813-820
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• 1998

This study was performed as a part of comparative biochemical studies of carotenoid pigment for the fresh water fish. Carotenoids in integument of Korean dark sleeper, Odontobutis platycephala, and dark sleeper, Odontobutis odontobutis interrupta, which are all the Korean native fresh water fish, were separated by thin layer chromatography, column chromatography and HPLC. The separated carotenoid were then reduced and isomerized by NaBH4 and I2 respectively to investigate UV-Vis spectrophotometeric patterns and chracterized by IR, 1H-NMR and Mass spectrum. The content of total carotenoids in the integument of Korean dark sleeper was 3.01mg% in April, but it was increased to 3.74mg% in September at the near of spawning period. The carotenoid isolated in April consisted of $\beta$-carotene(25.6%), lutein(18.5%) and zeaxanthin(12.0%) as major carotenoids and also contained isocryptoxanthin, diatoxanthin, tunaxanthin, cynthiaxanthin, canthaxanthin and $\alpha$-cryptoxanthin as minor carotenoids. Similarly, in September the carotenoid consisted of $\beta$-carotene(16.5%), zeaxanthin(13.7%) and cynthiaxanthin(13.6%) as major carotenoids and also contained lutein, isocryptoxanthin, tunaxanthin, $\alpha$-cryptoxanthin, diatoxanthin and canthaxanthin as minor carotenoids. At the near of spawning period, the content of cynthiaxanthin and $\alpha$-cryptoxanthin were increased. The content of total carotenoids in the integument of spawning period. T도 carotenoid isolated in April and September consisted of $\beta$-carotene(24.9%, 27.5%), zeaxanthin(14.4%, 20.9%) and lutein(12.6%, 11.4%) as major carotenoids and also contained cynthiaxanthin, tunaxanthin, diatoxanthin, isocryptoxanthin, $\alpha$-cryp-toxanthin and canthaxanthin as minor carotenoids. At the near of spawning period, the content of zeaxanthin was increased, indicating that the carotenoid composition were dependent upon their living conditions and their integument colors. Both Korean dark sleeper and dark sleeper contained high amount of cynthiaxanthin and diatoxanthin which are found as rare carotenoids in the other of fresh water fish. It is interes that they also contained tunaxanthin which is a specific carotenoid in marine fishes.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.143-147
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• 2024

This study aimed to determine the egg-hatching period of boreal digging frogs, Kaloula borealis, and investigate whether the incubation temperature affects the hatching period. In this study, the egg hatching was recorded based on the appearance of the tadpole. The results of this study showed that all the eggs hatched within 48 hours after spawning, with 28.1% (±10.8, n=52) hatching within 24 hours and 99.9% (±0.23, n=49) within 48 hours after spawning. The mean hatching rate of tadpoles showed significant differences depending on the difference in water temperature. The mean hatching rate between 15 and 24 hours after spawning was higher at a water temperature of 21.1 (±0.2) ℃ than at 24.1 (±0.2) ℃. The results suggest rapid hatching occurs at relatively low water temperatures because the spawning habits that spawn eggs in temporary ponds or puddles in the rainy season require rapid hatching before the puddles dry out. The results of this study are helpful for understanding the most suitable temperature conditions for the incubation of eggs of the endangered species, boreal digging frog.

• Journal of Aquaculture
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• v.11 no.2
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• pp.141-149
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• 1998

Spawning inducement of striped knife-jaw, Oplegnathus fasciathus, was attempted by two experiments. In experiment I (Exp. I), water temperature was gradually increased from 14.5$^{\circ}C$ in December 15, 1996 to $21.0^{\circ}C.$ in February 22, `997 and then maintained at this level. Photo-period was also gradually increased from 10.5L/13.5D in December 15, 1996 to 15.5L/8.5D in February 17, 1997, and then maintained at this level. In experiment II (Exp. II), water temperature was increased in the same way from Exp. I. Photoperiod was natural conditions from December 1996 to March 9, 1997, and then suddenly increased to 15.5L/8.5D until the end of experimental period. Spawning of the fish was occurred from February 22 through April 2, 1997 (for 40 days) in Exp. I. Number of total spawned eggs was 30.04 million and fertilization rate was 77.2%. The fish began to spawn at $21.0^{\circ}C.$ and 15.5L/8.5D. It requied 65 days to spawn since the water temperature had increased from $14.5^{\circ}C.$ to $21.0^{\circ}C.$. Spawning of the fish was not occurred until March 9, 1997 in Exp. II. After 7 days, photo-period was suddenly incresed to 15.5L/8.5D and fish were spawned from March 17 through April 4, 1997 (for 20 days). Number of total spawned eggs was 21.28 million and fertilization rate was 72.1%. The fish began to spawn at $21.0^{\circ}C$ and 15.5L/8.5D. It required 65 days to spawning since the water temperature had increased from $14.5^{\circ}C$ to $21.0^{\circ}C$.

• Journal of Aquaculture
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• v.1 no.1
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• pp.25-39
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• 1988

The flounder reared in captivity matured and spawned when the water temperature gradually increased to $14\~15^{\circ}C$ from $12^{\circ}C$ during winter and the diurnal photoperiod changed from 10L/14D in winter season to 14L/10D in spring. The eggs spawned naturally by reared spawners in captivity during the first half of a spawning period were superior in quality to those spawned during the later half. It would be better to use the eggs of the first half for the mass production of the seedlings.

• The Korean Journal of Zoology
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• v.8 no.2
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• pp.67-72
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• 1965

The breeding season of the bivalve, Lamprotula coreana , was observed in the vicinity of Achun-Ri of the Han River under the natural conditions. The effect of temperatures on spawning and attaching periods of the glochidia was also investigated in the laboratory. 1. The breeding season of Lamprotula coreana was lasted from October to April in the next year. The glochidia of Lamprotula coreana were observed in the outer gill layers, therefore they beling to the exobrachiae. 2. Each spawning of glochidia of Lamprotula coreana ended within 15, 12 , 7 and 5 days at 1$0^{\circ}C$, 15$^{\circ}C$, 2$0^{\circ}C$ and $25^{\circ}C$of water temperatures respectively. 3. The attaching period of glochidia of the Lamprotula coreana onto fish was longer at a low temperature than at higher one.

• Development and Reproduction
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• v.6 no.1
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• pp.37-44
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• 2002

First sexual maturity, sex ratio, spawning frequency, deposition of the egg capsules and fecundity of the female Rapana venosa(Valenciennes) inhabited in the artificially closed slag deposit area, Gwangyang Bay were investigated by histologicai and visual observations for natural living resource management. The rate of individuals reaching the first sexual maturity was 51.6％ in females measuring 7.1~8.0 cm in shell height, and 100％ in those > 10.1 cm. The total number of egg capsules per individual and the mean number of eggs in an egg capsule were 192~382 and 500, respectively. However, the number of eggs per individual and sizes of egg capsules under lower salinity and deficient food conditions in the closed slag deposit area were smaller than those under the optimum salinity and sufficient food conditions in the open regions. Fecundities of the species were approximately from 96,000 to 191,000 eggs/individual with two to low broods(spawning frequencies) during the spawning season. The duration of development in egg capsules was 18~19 days at about 18~2$0^{\circ}C$. R. venosa is a species whose embryos hatch as veliger larvae, not juvenile snail. The sex ratio of female : male was not significantly different from 1 : 1($\chi$$^2$= 0.23, p>0.05).