• Environmental Analysis Health and Toxicology
• /
• 제22권3호
• /
• pp.189-196
• /
• 2007

[ $TiO_2$ ] is widely used because it is non-toxic. Recently, however, nanometer size $TiO_2$ particles (P-25) have been produced and used to increase the photo catalysis efficiency. Nanometer-sized $TiO_2$ is efficient, but due to its small size ($20{\sim}30\;nm$), it can flow into ecosystems and into cells. Thus, it may affect human health. Additionally, $TiO_2$ can produce a second contaminant, OH-radical, which is a health risk for all living organisms during photo degradation reaction. Hence, when nanometer-sized $TiO_2$ flows into natural streams and attaches to living organisms, it will create health risks. We investigated the biological toxicity of this condition in zebrafish embryos. We observed abnormal morphology, hatching rate, and measured the catalase activity to determine anti-oxidation at 100 post fertilization hours. Zebrafish were somewhat affected by $TiO_2$ nanometer sized particles under UV-A (a condition similar to sunlight). Powdered $TiO_2$ is toxic to the zebrafish fly. Even without light, $TiO_2$ particles attached to embryos and flies, having an effect on both.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제37권2호
• /
• pp.100-104
• /
• 2018

The rearing of black soldier flies in Korea is affected by seasonal factors such as temperature and sun light; for this reason, it requires a great deal of effort to rear and maintain black soldier flies during the winter. In this study, we investigated how starvation affects larval development. After hatching the larvae, they were fed for 5 or 10 d and then starved for a certain period to see how they recovered. The length and width of larvae were estimated to be 18.18 to 21.96 mm, 5.19 to 6.04 mm, respectively. Larvae survivorship to the pupal stage was significantly different between groups and periods of starvation. The groups of fed for 5 d then starved showed a high survival rate until 20 d starvation and then the survival of larvae rapidly decreased. The survival rate of the larvae was abruptly decreased for 20 d starvation in the groups of fed for 10 d and starved, and then gradually decreased until 60 d starvation thereafter. Our research attempted to influence larvae development through starvation and provides basic information on how to culture the black soldier fly effectively and economically throughout the year.

• 한국응용곤충학회지
• /
• 제49권1호
• /
• pp.17-22
• /
• 2010

낙엽송잎벌은 1년에 3회 발생하는 전형적인 돌발해충으로, 암갈색 고치 속에서 전용 상태로 월동한다. 성충 우화시기는 강원지방에서 1화기가 5 월 7일~6월 3일, 2화기가 6월 20일~7월 13일, 3화기는 8월 4일~8월 25 일이었다. 산란수는 평균 59개, 난 기간은 평균 9 일정도 되었다. 부화율은 90% 이상이었다. 낙엽송가지 정단부쪽 제1, 제2, 제3 단지엽에 산란수가 많고 단지엽 뒷면 조직에 알을 절반 정도 삽입하여 산란하였다. 유충의 령기는 5령이고 유충기간은 20일 내외이다. 송잎별 유충은 장지엽(신초)보다는 단지엽을 선호하여 섭식하며, 노령유충은 지면으로 낙하하여 낙엽층 속이나, 표토 속에서 고치를 짓고 월동하였다.

• The Korean Journal of Ecology
• /
• 제8권2호
• /
• pp.119-126
• /
• 1985

One nest of the Common Kingfisher Alcedo atthis bengalensis Gmelin breeding in the area of Mt. Bangu, Mugye-ri, Jangye-ri, Jangyu-myon, Gimhae-gun, Gyongnam province, was observed for 43 days from July 18 to August 29, 1984. The nest was found at a height of 71cm in a steep mountain side. It was tunnel-shaped, with a size of 53cm(length), 5.5*6.4cm (the diameter of entrance) and 16.1*10.5cm (the diameter of incubation seat). The cluth size was 5 eggs. The eggs were white in color, the average size of 5 eggs being 20mm (length)*17.9mm(width). The incubation period was 18 days, the parent birds stayed in the nest at on average of 494 minutes and the rate of incubation was 82.20%. The incubation time increased gradually. The nesting period of 3 chicks was 25 days, and the average feeding frequency was 5, 50 times per day with the highest frequency of 10 times on the 14th days after hatching. The time and frequency of attendance gradually decreased as their chicks grew up. Total increase length in body was; body length 45.35longrightarrow147.80mm, wing 6.95longrightarrow63.40mm, bill 1.73longrightarrow29.36mm and body weight 2.93longrightarrow41.00gr. The prey for the 3 chicks of the nest was entirely fish. The main food item was the fry of Gobiobotidae. The home range of the nest was 0.43ha. and the territory size was 0.05ha. Their feeding ground were outside of their territory.

• 한국발생생물학회지:발생과생식
• /
• 제17권3호
• /
• pp.257-268
• /
• 2013

Morphometric changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. Yolk length, yolk height, and yolk volume in the two species decreased within 9 days post-hatching (DPH) (p<0.05). The body lengths and body heights of both species increased gradually to 150 and 130 DPH, respectively (p<0.05). The horizontal distance between the anteriormost extension of the head and the anterior insertion of the pectoral fin, the anteriormost extension of the head ${\times}$ the verticality position of the anterior insertion of the primary dorsal fin rays, and the anterior insertion of the primary dorsal fin ${\times}$ the anterior insertion of the pectoral fin were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). However, the relative sizes of the head region, pectoral fin, ventral fin, and anal fin were greater in the Ussurian bullhead than in the Korean bullhead (p<0.05), and relative body depth and the size of the outer-mandible barbel were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). The growth curves of the morphometric characteristics of both species were divided into three types.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제25권2호
• /
• pp.159-162
• /
• 2012

The Chinese windmill butterfly, Atrophaneura alcinous, is an important butterfly for exhibition in butterfly garden. The objective of this study was to determine the effect of temperature on A. alcinous in the laboratory. Development of A. alcinous reared on leaves of Aristolochia contorta was investigated at five constant the laboratory condition (20, 22.5, 25, 27.5 and $30^{\circ}C$) and at relative humidity of 60% with a photoperiod of 14:10 (L:D). Temperatures have been suggested as an important determinant of developmental rate, lifespan and mortality in invertebrates. As the temperature increased, the length of the developmental period gradually decreased. The developmental time (pupation) from egg hatching to pupation was respectively 25.8, 23.6, 19.6, 15.5, and 12.9 days at the temperatures of 20, 22.5, 25, 27.5 and $30^{\circ}C$. And pupation was respectively 40.0, 30.0, 63.4, 50.0, 23.3% at the temperatures of 20, 22.5, 25, 27.5 and $30^{\circ}C$. The developmental threshold temperature estimated for egg-to-pupae was 10.8, with a thermal constant of 230.4 degree-days. Therefore, the optimal developmental temperature for A. alninous was determined to be $25^{\circ}C$. To compare the effects of the total duration of chilling on the termination of diapause, larvae were subjected to a temperature of $8^{\circ}C$ from 60 to 120 days. The rate of termination of diapause was significantly higher at 60 days compared to other incubation period.

• Fisheries and Aquatic Sciences
• /
• 제12권4호
• /
• pp.350-353
• /
• 2009

As a result of human industrial development, carbon dioxide ($CO_2$) is currently accumulating in the atmosphere and dissolving into the oceans. Sequestration into the deep sea has been proposed as a possible solution to this increasing atmospheric $CO_2$, although the impact of such a program on marine ecosystems is unknown. We examined the effects of increased $CO_2$ levels on the growth of the olive flounder, Paralichthys olivaceus. Juvenile olive flounder 40 days post hatching were exposed to two levels of $CO_2$ (3.60-7.55 and 4.05-11.46 kPa) in running seawater for 26 days. During the exposure period, the pH and $CO_2$ levels of the water were measured, and the numbers of dead individuals were counted in each aquarium. Following the exposure period, the total lengths (mm) and body weights (mg) of the juvenile fish were measured. Both $CO_2$ treatments significantly increased fish mortality compared to controls ($19.87\pm4.53%$ vs. 7.14% and $75.96\pm1.36%$ vs. 7.14% for high and low doses, respectively). After the high $CO_2$ treatment, total length ($14.98\pm6.58$ mm vs. $19.52\pm1.83$ mm) and body weight ($28.92\pm13.85$ mg vs. $67.35\pm18.32$ mg) of the exposed flounder were reduced compared to the control fish; however, no significant differences in these values were observed after the low $CO_2$ dose. These results suggested that $CO_2$ exposure inhibits growth in the juvenile stage and that $CO_2$-enriched seawater is toxic in the early life stages of olive flounder.

• 한국발생생물학회지:발생과생식
• /
• 제18권3호
• /
• pp.127-131
• /
• 2014

We investigated the androgenic effects of $17{\alpha}$-methyltestosterone (MT) on gonadal sex reversal in juvenile red spotted grouper Epinephelus akaara. The fish were immersed in $17{\alpha}$-MT at 1 and 5 mg/L. Treatment method of $17{\alpha}$-MT was once weekly for 4 and 8 weeks. Fish were sampled at 12 months after end of the treatment period in order to histological analysis. At the initiation of an experiment (70 day after hatching), juvenile red spotted grouper have the paired primordial gonads with somatic cells bellow kidney in the posterior portion of the body cavity. Formation of ovarian cavity indicates that the ovarian differentiation beginning at 70 DAH in red spotted grouper. At 12 months after end of the treatment period, control group, $17{\alpha}$-MT 1 mg/L treatment group for 4 and 8 weeks, and $17{\alpha}$-MT 5 mg/L treatment group for 4 weeks were all female. However, sex-changed males without ovarian cavity were observed in the $17{\alpha}$-MT 5 mg/L treatment group for 8 weeks. In grouper, we firstly reported that the red spotted grouper be able to induce the primary males by hormone treatment prior to gonadal sex differentiation.

• 한국수산과학회지
• /
• 제29권1호
• /
• pp.26-34
• /
• 1996

1992년 5월부터 1993년 8월까지 부산 수영만 인근해역에서 채집된 망상어, Ditrema temminck의 교미 및 임신과 관련된 사항을 조직학적으로 조사한 결과는 다음과 같다. 교미시기에 성숙한 수컷은 뒷지느러미 연조의 좌우 기저부에 각각 하나씩 교미기가 돌출된다. 교미에 참여한 수컷의 이차성징지수는 3.5이상으로 나타났으며, 암컷에서 성숙난은 난소강내에 정자를 보유한 개체에서만 나타났다. 교미시 정자의 난소강내 수송형태는 정포형태이며, 교미후 난소강내의 정자는 수정시까지 약 1개월 정도의 잠복기를 가진다. 수정형은 여포강내 수정형이고, 임신형은 난소강내 임신형이며, 암컷의 발생학적 과정은 수정-배란-부화-출산으로 이어진다. 출산직전 체내자어의 크기는 전장 63.0cm정도이며, 평균 체내자어수는 모체가 전장 20.0cm인 경우 18마리 였으며 모체의 크기가 증가함에 따라 증가하는 경향을 보였다.

• 한국어류학회지
• /
• 제35권4호
• /
• pp.294-304
• /
• 2023

가덕도 인근해역에서 출현하는 자어 군집에 대한 계절변동을 파악하기 위해 2019년 5월, 8월, 11월 그리고 2020년 2월에 조사를 실시하였다. 조사기간 동안 자어는 총 45과 85개 분류군이 출현하였다. 우점종은 멸치(Engraulis japonicus), 망둑어류(Gobiidae spp.), 청어(Clupea pallasii), 가라지(Decapterus maruadsi), 돛양태류(Callionymidae sp.) 등으로 나타났으며, 이들 5종은 조사기간 중 출현한 자어 전체 출현개체수의 84.1%를 차지하였다. 멸치와 망둑어류, 가라지, 돛양태류는 여름철 우점종이었고, 청어는 겨울철 우점종이었다. 종다양도지수는 여름철에 가장 높고 가을, 겨울철로 갈수록 낮아졌으며, 봄철에 가장 낮은 값을 나타내었다. 조사기간 동안 출현한 자어의 출현개체수로 군집분석을 실시한 결과 계절에 따라 4개의 그룹으로 뚜렷이 구분되었다. 특히, 계절적 수온변화에 따라 여름철에는 자어의 적정한 성육환경이 형성되었고, 겨울철에는 겨울산란어종의 적정한 부화수온이 형성되어 자어군집의 계절적 특성을 반영하고 있었다.