• Animal cells and systems
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• 제7권4호
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• pp.345-348
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• 2003

The effects of acute acid stress on hatching success and hatching period of laboratory-reared hermaphroditic fish Rivulus marmoratus were examined. The effects of acute acid toxicity on mortality was also determined in three life stages of this fish. There was a significant negative effect of acid stress on hatching performance in the R. marmoratus embryos. The hatching success was only 5% at pH 3.5 compared to over 78% at pH higher than 4.0. The hatching period was also delayed by low pH treatments. The larval and juvenile stages were more sensitive to acid toxicity on mortality than the adult stage, but larvae and juveniles showed similar sensitivity. The 96-h LC50 value was pH 3.8 in larval and juvenile stages and pH 3.3 in adult stage.

• Journal of Ecology and Environment
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• 제38권4호
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• pp.415-424
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• 2015

This research was conducted to reveal the characteristics of breeding ecology of oriental scops owl (Otus sunia stictonotus) inhabiting in South Korea according to the nest types during the breeding season from march to October for two years (2011 and 2012). Oriental scops owl nested in woodpecker's nest holes (46.1%), natural tree holes (38.5%), and artificial wood boxes (15.4%). These nests were located on following trees: Zelkova serrata, Paulownia coreana, Celtis sinensis, Salix chaenomeloides, Salix babylonica, Fraxinus rhynchophylla, Robinia pseudoacacia and Platanus occidentalis. The hatching success was 91.4%, fledging success was 83.0%, and breeding success was 75.9%. The factors of the breeding failure were falling (57.1%), abandonment (28.6%), hatching failure (7.1%), and others with unknown cause of death (7.1%). According to nest types, the fledging success (69.2%) of woodpecker's nest holes were low and the hatching success (79.2%) of natural tree holes were also low due to hatching failure and abandonment. However, hatching success, fledging success, breeding success were high in the artificial nests as all the eggs hatched and succeeded in fledging. Therefore, we suggested that artificial nests can cover the weaknesses of natural nests as well as increasing the breeding success. However, long-term research on installation place, height, and hole sizes of the artificial nest are required in order to clearly reveal the effects on the breeding success of oriental scops owl.

• Journal of Ecology and Environment
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• 제29권1호
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• pp.35-39
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• 2006

During the breeding seasons in 2002 and 2003, the influences of vegetation cover on breeding processes of Black-tailed Gulls (Laurs crassirostris) were studied on Hongdo Island. We checked dutch sizes, calculated hatching success and survival rates on day 15 and a vegetation cover, There was significant positive relationship between vegetation cover and hatching success, and survival on day 15. In order to analyze the relationship, sample nests were categorized as 'exposed' and 'covered' nests, and the breeding processes at each nest were compared. Hatching success and survival on day 15 in covered nests were significantly higher than ones in exposed nests. However, in clutch size, there was no significant difference. The rate of the hatching and survival failure was different amongst the categorized nests. The primary cause of hatching failure in covered and exposed nests was 'disappeared', and the primary causes of survival failure on day 15 were 'disappeared' and 'killed by adults'. The failure in exposed nests was significantly larger than that of covered nests. In the breeding of Black-tailed Gulls on Hongdo Island, vegetation cover influenced the survival of eggs and chicks as the cover provided shelter against predators and extreme weather.

• Journal of Ecology and Environment
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• 제31권3호
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• pp.201-206
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• 2008

This study was conducted to determine clutch size and habitat usage of Kentish plovers (Charadrius alexandrinus) breeding on Sinja-do lslet in the Nakdong Estuary from 22 April to 12 July in 1995 and from 21 April to 20 June in 1996. The Kentish plover preferred grasslands and damp sands to dry dunes as nesting sites. The difference in hatching success among these microhabitats was attributed to high tides, which washed away many nests on damp sands, and strong winds, which frequently shifted the sand to bury eggs on dry dunes. The main mortality factor in grasslands was predation by magpies Pica pica. Each clutch contained one to four eggs, with a mode of three eggs. Hatching success was highest in two-egg clutches and lowest in one- and four-egg clutches. The mean interval for egg laying was 1.8 days between the first and second eggs and 2.1 days between the second and third eggs. The average incubation period was about 24.2 days.

• 한국양식학회지
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• 제14권1호
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• pp.17-27
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• 2001

Effects of temperature (10, 12, 14, 16, 18 and 2$0^{\circ}C$) and salinity (22.0, 24.5, 27.0, 29.5, 32.0 and 34.5 ppt) were studied on incubation period, hatching success, survival and growth of alevin and juvenile seabass, L. japonicus. Embryonic development was accelerated with increasing temperature but it was not influenced by salinity. Hatching success was the highest at 14$^{\circ}C$ and 34.5 ppt. Higher temperature also accelerated the development of mouth opening, absorption of yolk and oil globules, and alevin growth. Survival of the 5-day old Juvenile was accelerated in the following order : 14<16<18<20<12$^{\circ}C$. Rearing experiment of the juvenile for 30-day indicated the faster growth at 13, 20 and 27 ppt than at 34 ppt.

• Ocean and Polar Research
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• 제28권2호
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• pp.201-207
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• 2006

We studied variation in clutch size, hatching, fledging and breeding success of the Black-tailed Gull (larus crassirostris) at Hongdo Island, which supported the largest breeding colony of the species, in South Korea in 1997 and 2000 to 2003. Cluck size was recorded in 1,388 nests and breeding success was estimated in 83 nests. Mean clutch size was 1.89 t 0.65. A total of 63.9% of the eggs hatched and 53.5% of the chicks survived until fledged. Breeding success was 34.2%. Causes of breeding failure were eggs missing (14.9%), rotten eggs (15.5%) and predation (2.4%) during the incubation period and chicks missing(35.8%), starvation (7.4%) and pecked chicks (3.2%) during the chick rearing period. In 2002, the main causes of breeding failure were eggs missing (17.2%) and rotten eggs (6.9%) during the incubation period and missing chicks (15.5%), starvation (3.5%) and pecked chicks (6.9%) during the chick rearing period. Most chick mortality occurred within three days after hatching.

• 한국환경생태학회지
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• 제22권1호
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• pp.59-65
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• 2008

본 연구는 2005년부터 2007년까지 파주, 강화도, 이천, 시화호, 충주 등 5개 지역에 서식하는 수리부엉이 9쌍의 둥지를 정기적으로 촬영, 관찰하여 번식생태와 교미행동을 연구하였다. 한배산란수는 $1\sim4$개로 평균 2.77개(n=15)였으며, 부화성공률은 약 71%(n=34)였고, 이소성공률은 약 83%(n=23)였다. 수리부엉이는 산란이 끝난 후에도 암수간의 교미행동이 지속되며, 새끼들이 둥지를 떠나는 시기인 부화 후 $7\sim8$주까지 교미행동을 계속한다는 것을 확인하였다. 이러한 수정 목적 이외의 교미 행동은 암컷과 수컷 모두의 필요에 의해서 이루어지는 것으로써 '부부관계(pair-bond)'의 확인, 유지, 강화를 통해 새끼를 안정적으로 키우기 위한 것으로 해석된다.

• 환경생물
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• 제38권4호
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• pp.625-633
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• 2020

The effects of temperature and salinity on egg development and settlement of the ascidian Herdmania momus were investigated. Adult specimens were collected from the Dodu Yacht facility in Jeju Island, Korea(33°30'30.54"N, 126°27'55.46"E) in August 2018. Egg development and larval settlement were observed and recorded at 8 h intervals using a stereomicroscope, under nine temperature (10, 13, 16, 19, 22, 25, 28, 31, and 34℃), and four salinity regimens (28, 30, 32, and 34 psu). The highest hatching rate (82.8±7%) was observed at 32 psu and 25℃ and the lowest hatching rate (1.0±2%) was at 34 psu and 13℃. The developmental rate (0.222±0.0994) was highest at 28 psu and 28℃, and lowest (0.016±0.008) at 30 psu and 13℃. The highest settlement success rate (77.1±5%) was at 32psu and 25℃ and the lowest(0.1±1.0%) was at 30psu, and 13℃. The rate of settlement(0.080±0.000) was highest at 28psu and 28℃, and lowest(0.013±0.000) at 30psu and 13℃. Both hatching and settlement success rates increased as temperature increased and tended to decrease beyond an optimal temperature range. Herdmania momus preferred 30-34 psu salinity and 22-25℃ temperature. This study provides baseline information about the life history of H. momus, and important data to control the damage caused by the increase in number and distribution of this invasive ascidian.

• 생명과학회지
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• 제19권11호
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• pp.1611-1616
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• 2009

본 연구는 1990년대 중 후반기(1995년, 1996년, 1998년)와 2000년대 중반기(2004년, 2005년)에 조사한 쇠제비갈매기의 번식에 관한 자료를 분석하여 낙동강 하구의 최남단에 위치하고 있는 신자도와 도요등에서의 쇠제비갈매기(Little Tern Sterna albifrons)의 번식 상황의 변화를 알아보고자 수행하였다. 신자도에서는 1995년에 쇠제비갈매기의 둥지 638개를 조사하였는데, 한배 산란 수는 평균 2.48개이었고, 1996년에는 총 106 둥지를 조사하였는데, 한배 산란 수는 2.35개이었으며, 2004년에는 총 94 둥지를 조사하였는데 한배 산란 수는 평균 2.16개이었다. 2005년에는 총 456 둥지를 조사하였는데 한배산란 수는 평균 2.53개 이었고, 4년간의 한배 산란 수에는 통계적으로 유의한 차이가 있었다(p<0.001). 도요등에서는 1998년에 총 263 둥지를 조사하였고 한배 산란 수는 평균 2.18개이 었고, 2004년에는 총 1,023 둥지를 조사하였는데 한배 산란수는 평균 2.33개이었으며, 2005년에는 총 1,123 둥지를 조사하였는데 한배 산란 수는 평균 2.52개 이었다. 3년간의 한배 산란수에는 통계적으로 유의한 차이가 있었다(p<0.001). 신자도에서의 쇠제비갈매기의 부화 성공률은 54.5%이었으며, D형 둥지와 A형 둥지에서 높았고 C형 둥지에서 낮았다. 부화 실패 요인으로서는 범람이 가장 큰 요인이었으며 특히 C형 둥지에서 그러하였다. 도요등에서의 부화 성공률은 73.2%이었으며, D형 둥지와 A형 둥지에서 높았고 C형 둥지에서 낮았다. 부화 실패요인으로서는 범람이 가장 큰 요인이었으며 특히 C형 둥지에서의 영향이 컸다. 낙동강 하구의 사주는 앞으로도 많은 변화가 예상되지만, 쇠제비갈매기 등의 번식지로서의 기능을 다하기 위해서는 포식자의 퇴치와 사주의 육화 방지와 모래가 있는 나대지를 유지하기 위하여 갈대제거 등 지속적인 관리가 절실히 요구된다.

• 한국어병학회지
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• 제20권3호
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• pp.257-267
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• 2007

The hypo-salinity effects on fertilized eggs, embryos and larvae were investigated in olive flounder (Paralichthys olivaceus) obtained from hatcheries in Cheju-Island, Yeosu and Chungnam. Those were treated to eight concentration; 0, 3.4, 6.7, 10.1, 13.4, 20.2, 27.4 and 33.6 ‰. It was not discrepancy in the survival rate and hatching success rate of fertilized embryos obtained from different regions. Also, in the larvae, the regional difference was not appeared. The survival rate and hatching ability of embryos significantly diminished in the lower groups than 13.4 ‰ compared to 33.6 ‰. After fertilization, namely embryos are tolerant of a wide range of salinity (13.4 - 33.6 ‰). Reduced salinity induced an increase of the malformed embryo and larvae including various deformities; irregular embryos membrane (or yolk sac depression), fin erosion and swim bladder inflation in the flounder embryo. The hatching success of embryos was significantly reduced in lower salinity than 13.4 ‰. Notably, the reduction of larval survival rate significantly was observed in ≤10.1 ‰ treated groups with the same manner of survival rates of the embryos. Additionally, olive flounder was found to be adequate model for measuring external impulses because there are no the regional differences.