• Journal of Ecology and Environment
• /
• v.29 no.1
• /
• pp.35-39
• /
• 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
• /
• v.38 no.4
• /
• pp.415-424
• /
• 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 Forest and Environmental Science
• /
• v.28 no.4
• /
• pp.220-226
• /
• 2012

An assessment of Marsh crocodile's (Crocodylus palustris LESSON, 1831) habitat, its feasibility in supporting the total population, feeding, hatching difficulty and variations in egg and clutch size of Marsh crocodile were carried out in Bangabandhu Sheikh Mujib Safari Park for one year (July 2010 to June 2011). Major problem identified was the breeding failure, i.e. till now no hatching were found. Mainly two local weather variables (average temperature and humidity) were identified as the most obstructing parameters. Higher temperature (average $37.03^{\circ}C$) and Lower Humidity (average 75.33%) in comparison with standard range of incubation temperature and humidity for Marsh crocodile were seems to be vital reason for the failure of hatching. Understanding of the identified problem of this paper can direct the wildlife conservationist and the policy maker to take proper action for conserving the Marsh Crocodile in Bangladesh.

• Clinical and Experimental Reproductive Medicine
• /
• v.25 no.2
• /
• pp.123-128
• /
• 1998

Implantation rates remain low following human in vitro fertilization (IVF). Suboptimal culture conditions may limit the ability of embryos to hatch as blastocysts, and artificial opening of the zona pellucida has been proposed as a means to promote subsequent hatching (assisted hatching). In this study, assisted hatching (AH) by zona drilling using acidic Tyrode's solution was performed in 320 patients, due to their age of more than 38 years (group A), the thick zona pellucida (group Z; $ZP\geq0.18{\mu}m$), and failures in implantation more than 3 times in previous IVF-ET trial (group P). This study was designed firstly, to study the effects of AH on the outcomes of IVF-ET according to the indications and secondly, to verify the appropriate application of AH. The results were as follows; 1. There was no difference in pregnancy rate between AH group (26.6%) and non-AH group (26.5%). 2. Assisted hatching (AH) showed significantly higher pregnancy rate of the patients with thick zona pellucid a than those of the patients with age factor and with the history of repeated implantation failure. But in the patients with age factor only, AH resulted in higher pregnancy rate. 3. Interestingly, the patients with complex factors including zona factor (Z: 33.9%; ZA: 30.4%; ZP: 31.6%; ZAP: 21.4%) showed higher pregnancy rates than other complex factors excluding zona factor (A: 24.4%, P: 0%; AP: 10.8%). From these results, AH is more helpful to the patients with thick zona pellucida rather than patients with older age and/or previous repeated implantation failure.

• Ocean and Polar Research
• /
• v.28 no.2
• /
• pp.201-207
• /
• 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.

• Journal of Life Science
• /
• v.19 no.11
• /
• pp.1611-1616
• /
• 2009

This study was conducted to determine the characteristics in breeding of the little tern Sterna albifrons in Shinja-do and Doyo-Deung in Nakdong estuary. The data was obtained in the middle and late 1990's and in the mid 2000's, which were analysed for the breeding information of the little tern. In Shinja-Do, a total of 638 nests were observed in 1995, and the average numbers of eggs laid per nest were 2.48. In 2004 and 2005, 94 and 456 nests were observed, and the average number of eggs laid per nest was 2.16 and 2.53, respectively. There was a significant difference between the average numbers of eggs laid per nest for the 3 respective years. In Doyo-Deung, a total of 269 nests were observed in 1998, and the average number of eggs laid per nest was 2.16. In 2004 and 2005, 1,023 and 1,123 nests were observed, and the average numbers of eggs laid per nest were 2.33 and 2.52, respectively. There was a significant difference (p<0.001) between the average number of eggs laid per nest as well. Hatching success rate by nesting site in Shinja-Do was calculated in 1995. Type A nest (nest located on dry sand land) showed a 56.8% success rate, and type B nest (nest located on the land with dwarf grass), type C nest (nest located on moist land) and type D nest (nest located on the land with shells) showed 55.3%, 36.6% and 59.3% success rates, respectively. The average hatching success rate in Shinja-Do was 54.5%. The most crucial factor for hatching failure was flood, especially, for the type C nests. The hatching success rate by the nesting site in Doyo-Deung showed an average of 73.2%. It was high in type D nest (83.8%) and type A nest (75.9%), and low in type C nest (59.7%). Again, the most crucial factor for hatching failure was flood, especially, for the type C nests. Nakdong estuary has been through many changes over time, particularly in recent. Therefore, continuous efforts to keep it a breeding place for the little tern are urgently required, including overall management of land, protection of reef and sand, etc.

• Clinical and Experimental Reproductive Medicine
• /
• v.35 no.3
• /
• pp.193-202
• /
• 2008

Objective: To evaluate efficacy of assisted hatching by laser (AHL) and acidified Tyrode solution (AHA) in selected groups of IVF-ET patients who have a poor prognosis. Methods: From February 2006 to September 2006, total of 328 IVF-ET cycles with advanced female age (${\geq}38$ years), recurrent implantation failure (${\geq}3$ cycles), thick zona (${\geq}17{\mu}m$), and/or poor quality of embryo were randomly divided into assisted hatching by acidified Tyrode solution (AHA, n=180) and the assisted hatching using the ZILOS-tk laser (AHL, n=148) groups. Clinical outcomes were analyzed and compared between AHA and AHL group based on the patient characteristics. Results: In all AHL and AHA group, there were no significant differences in pregnancy (42.6%, 63/148 vs. 33.3%, 60/180) and implantation rates (17.4%, 82/470 vs. 16.0%, 89/556) However, in advanced female age group (Group 1), pregnancy (37.0%, 20/54 vs. 18.7%, 14/75) and implantation rates (14.4%, 23/160 vs. 7.1%, 15/210) in AHL group were significantly (p<0.05) higher than those of AHA, although there was no difference in patient parameters of both groups. And, the clinical outcome of groups with recurrent implantation failure (Group 2), thick zona pellucida (Group 3) and poor quality embryo (Group 4) were improved in AHL compared to those of AHA: 43.8% (21/48) and 31.6% (25/79) in Group 2, 43.8% (32/73) and 34.1% (28/82) in Group 3, 25.0% (7/28) and 14.6% (6/41) in Group 4, but no significance. Conclusion: The AHL improved the pregnancy and implantation rates in patients with advanced female age and recurrent implantation failure when compared to outcomes achieved from AHA. Therefore, this AHL technique may be a efficient and safe method for patients with poor prognosis.

• Korean Journal of Poultry Science
• /
• v.23 no.2
• /
• pp.77-84
• /
• 1996

The purpose of this paper is to introduce the present situation of broiler breeder industry, and to investigate some problems related to it in Korea. The number of broiler breeding farms were 231 in 1990. It peaked to 264 in 1992, but decreased afterward to 232 in 1995. The number of broiler parent stock were over 4 millions since 1992 except in 1993. The number of commercial chicks produced per breeding hen was around 100, which is far below to the suggested values of breeding companies. The number of hatching eggs produced per breeding hen were 168 eggs in US, 156~170 eggs in Thailand, and 160~170 eggs in China. Factors involved in the lowered performances of broiler parent stock in Korea appear to be 1) the poor isolation of breeding farms from commercial broiler farms, causing easy contamination with various diseases, 2) the failure to provide proper environment to the breeder, and 3) the failure to control body weight during laying periods.

• Environmental Analysis Health and Toxicology
• /
• v.21 no.4 s.55
• /
• pp.323-330
• /
• 2006

The aim of current study was to evaluate the toxicity of nonylphenol(NP) on soil nematode, Caenorhabditi elegans. The stress-related gene expression, growth, reproduction and development have been employed to monitor soil toxicity. The 24-h median effect concentrations $(LC_{50s})$ of NP was $0.15mg/L$. The expressions of vitellogenin-6, vitellogenin-2, cytochrome P450 family protein 35a2 and apoptosis enhancer-1 genes were upregulated in C. elegans by NP exposure. Alterations in growth, reproduction and development were also observed in NP-exposed group and especially hatching failure was observed. The overall results indicate that C. elegans has considerable potential as sensitive markers for NP toxicity monitoring.

• Ocean and Polar Research
• /
• v.31 no.3
• /
• pp.277-282
• /
• 2009

Saunders' gulls (Laurs saundersi) which are listed as globally vulnerable species on the IUCN Red List are distributed in East Asia and breed mainly in China and Korea. Their population is estimated to be between 7,100 to 9,600. Songdo reclaimed lands in the western coast of South Korea are the main breeding sites for these species. However, most of these breeding sites have been seriously disturbed in the last several years because of new urban development constructions. This study was conducted to provide baseline data on the breeding ecology of Saunders' gulls. Since 1998, the breeding population has rapidly increased in South Korea, with the number of nests rising from 85 nests in 2000 to 185 nests in 2005. Egg volume is more variable than breadth or length. Clutch size, hatching and breeding success were $2.9{\pm}0.81$ (n=182, mean$\pm$sd.), 48.07% (75 hatched egg/156 eggs) and 29.08% (155 fledglings/533 eggs), respectively. Factors affecting breeding failure were predation, rainfall, starvation and supernormal clutches. These results are provided along with other cited literature to argue for conservation of Saunders' gulls.