• Korean Journal of Ichthyology
• /
• v.13 no.1
• /
• pp.74-84
• /
• 2001

The early developmental stages, growth and morphological changes of the Korean bullhead, Pseudobagrus fulvidraco, were studied from a series of reared specimens. Details of the early developmental stages are illustrated with special reference to morphological transformations. Egg and sperm of Korean bullhead were obtained from mature adults under hormonal treatment, fertilized artificially, and incubated in the aquarium. The incubation period of fertilized eggs was 55 to 66 hours at a temperature of 24.9${\pm}$0.34$^{\circ}$. Larvae were fed successively with Artemia salina and Daphnia magna for 2 to 15 days and artificial food after 20 days. Fertilized eggs were adhesive and spherical with a diameter of 2.04mm(n = 100). The mean total length of newly hatched larvae was about 4.92${\pm}$0.33 mm. Mouth opening occurred on one-day-old yolk-sac larvae, and initial feeding was observed on the third day after hatching. The morphological transitions from larvae to juvenile and juvenile to young stages occurred when the fish reached about 17 mm in total length (about 13days after hatching) and about 32 mm in total length (about 30 days after hatching), respectively. Many changes in proportion of body parts to total length were observed at about 7~8 mm and 30~32 mm, corresponding to the transformations from larvae to juvenile and from juvenile to young, respectively. In comparing relative growth of each body part against total length, those characteristics related to head parts showed positive growth in the pre-larval stages, while those concerning mobile abilities showed positive growth in the post-larval stage.

• Korean Journal of Ichthyology
• /
• v.30 no.2
• /
• pp.75-83
• /
• 2018

This study is to observe species identification and early life history of Korean endemic species of Tanakia latimarginata and to use it as a basis for taxonomic studies. As a result of morphological identification, a dark band appeared at the margin of the anal fin, and the ovipositor color of the female was light orange. The shape of the egg was fusiform and sticky. The egg size (long${\times}$short diameter) averaged $4.41{\times}1.44mm$. The incubation time was 126 hours after the fertilization at an average water temperature of $21.0^{\circ}C$. Immediately after hatching, the larvae had egg yolk at an average total length of $5.91{\pm}0.18mm$ (n=5). At 18 days after hatching, the trunk fur was developed in the caudal fin with an average total length of $8.02{\pm}0.08mm$ (n=5). At 41 days after hatching, the larvae absorbed egg yolk at an average total length of $8.70{\pm}0.23mm$ (n=5). At 80 days after hatching, the average length of the fins was $12.6{\pm}0.28mm$ (n=5). The number of fin of the dorsal fin was iii.8, the anal fin iii.9~10, the caudal fin 19, lateral line scales 32~35 were similar to their brood stork.

• Korean Journal of Ichthyology
• /
• v.35 no.2
• /
• pp.91-100
• /
• 2023

The early life history of Silurus microdorsalis living in Jahocheon Stream was studied by observing egg and morphological development. Live fish were captured in June 2018, then reared in a circulating filtration system under a 14L : 10D photoperiod with a water temperature of 18℃. To artificially induce spawning, females were injected with 0.5 mL of Ovaprim (Syndel, Nanaimo, BC, Canada) per kg of body weight, and males were injected with 10,000 IU/kg body weight of human chorionic gonadotropin. Approximately 15 h later, eggs were artificially inseminated by the dry method. Mature eggs were light pale yellow, which separated them from immature eggs. Fertilized eggs were 2.16±0.06 mm (n=8) in diameter and fully hatched at 181 h after fertilization. The fertilization rate was 63.1±2.2%, and 10.0±3.7% of the embryos were malformed at 18℃. The rates of development were 181 h at 18℃, 109 h at 21℃, and 76 h at 24℃. The larval size immediately after hatching was 4.64±0.22 mm (n=8), and the larvae displayed negative phototaxis at 1 day after hatching. The total larval length on 7 days after hatching was 12.47±0.53 mm, with 25~30 basal anal fin rays and 14~16 basal caudal fin rays observed. The total larval length was 14.13±0.51 mm on 9 days after hatching, and approximately 90% of the black endoplasmic reticulum was deposited on the head and body. The dorsal fin had formed, and a single basal body was observed. On 15 days after hatching, the total larval length was 16.69±0.31 mm; the number of basal caudal fin rays (18 poles) was an integer because 2 dorsal fin basal rays and 60~63 anal fin basal rays were observed. The total larval length was 28.96±1.10 mm on 50 days after hatching; the numbers of caudal fins (n=18), dorsal fins (n=3), pectoral fins (n=11), and anal fin basal rays (n=67~73) were integers.

• Korean Journal of Ichthyology
• /
• v.26 no.1
• /
• pp.17-24
• /
• 2014

The egg development and early life history of Acheilognathus majusculus which is Korean endemic species from Yeong river were observed under the controlled water temperature, $18.0{\pm}1.0^{\circ}C$. Fertilized eggs are opaque yellow in color and round oval shaped measuring 2.12 (2.08~2.18) mm in length and 1.86 (1.80~1.98) mm in breadth. The number of eggs averaged 72 (40~112) per an oviposition. The eggs of this species began to hatch about forty three hours after insemination and the total length of larvae was 4.23 mm mean. S form moving of larvae were not observed during larval development. The larvae reached at the heterotrophic stage about twenty-five days after hatching. It is estimated that the larvae was comming out from freshwater bivalve since that time in nature. A. majusculus was grew up to be adult stage enough which can be join to new production for three hundred days after hatching with over 67.8 mm in total length.

• Korean Journal of Ichthyology
• /
• v.21 no.3
• /
• pp.141-148
• /
• 2009

Sex differentiation and gonad development were investigated in a marine medaka species, Oryzias dancena (Beloniformes; Teleostei). The average time to hatch was 11 days post-fertilization (dpf) at $25^{\circ}C$. Primordial germ cell (PGC) was first observed at 5 dpf and migrated to presumptive gonadal area between the gut and pronephric duct at 9 dpf. Male and female gonads were morphologically differentiated at 12 days post-hatching (dph). Early oocytes at perinucleolus stage as well as the formation of spermatid and efferent duct were observed at 28 dph. At 6 weeks of age, the ovary exhibited yolk granulation in many oocytes, while testis possessed a considerable number of spermatogonia and spermatids. The first ovulation was observed in 9-week-old females, and at the same age, males contained fully-matured spermatozoa. Data obtained in this study indicate that the gonad differentiation of O. dancena is the typical type of differentiated gonochorism.

• Korean Journal of Ichthyology
• /
• v.24 no.2
• /
• pp.101-109
• /
• 2012

The egg development and early life history of Acheilognathus macropterus from Japan which is an exotic bitterling from China were observed under the controlled water temperature, $20.0{\pm}1.0^{\circ}C$. Fertilized eggs are opaque yellow in color and long elliptic globe shaped measuring $2.78{\pm}0.12mm$ in length and $1.44{\pm}0.04mm$ in breadth. The number of egg averaged 151 per an oviposition. The eggs of this species began to hatch about seventy eight hours after insemination and the mean of total length of larvae were 3.8 mm. S form moving of larvae were observed from three days after hatching. The larvae reached at the heterotrophic stage about twenty-five days after hatching. Morphological character and analysis of cytochrome DNA of this species from Japan were relatively similar to Korean but spawned egg shape was different remarkably. Taxonomical research is necessary in the future.

• Journal of Broadcast Engineering
• /
• v.8 no.1
• /
• pp.19-29
• /
• 2003

The demand for high-resolution images is gradually increasing, whereas many imaging systems yield aliased and undersampled images during image acquisition. In this paper, we propose a high-resolution image reconstruction algorithm considering inaccurate subpixel registration. A regularized Iterative reconstruction algorithm is adopted to overcome the ill-posedness problem resulting from inaccurate subpixel registration. In particular, we use multichannel image reconstruction algorithms suitable for application with multiframe environments. Since the registration error in each low-resolution has a different pattern, the regularization parameters are determined adaptively for each channel. We propose a methods for estimating the regularization parameter automatically. The preposed algorithm are robust against the registration error noise. and they do not require any prior information about the original image or the registration error process. Experimental results indicate that the proposed algorithms outperform conventional approaches in terms of both objective measurements and visual evaluation.

• The Korean Journal of Ecology
• /
• v.28 no.5
• /
• pp.281-286
• /
• 2005

The ripe unfertilized eggs of Acheilognathus signifer were elliptical shape and baggily swollen toward animal pole. The size of fertilized eggs were $2.19{\pm}0.01$ mm in long axis and $1.85{\pm}0.08$ mm in short axis and oil globe were not observed. The zona radiata of A. signifer had the structure of regular fibrilar net and the diameter of outer opening micropyle was about $2.5{\mu}m$ and that of inner opening micropyle was about $1.5\sim2.0{\mu}m$. Development of fertilized eggs in A. signifer was proceeded in inclining position of animal pole and hatched in 49 hours under $20{\pm}1^{\circ}C$. The yolk sac was absolutely absorbed in 21 days after hatching.

• Monthly Korean Chicken
• /
• v.16 no.6
• /
• pp.124-126
• /
• 2010

양계인이라면 누구나 생독백신 접종 후에 나타나는 백신접종반응(기침 등 호흡기 증상)은 적으면서 백신접종효능(항제 형성능 및 질병방어효과)은 아주 우수한 그런 종류의 생독 백신이나 접종법을 찾게 마련이다. 국내의 경우 1일령 병아리에 대한 닭 뉴캣슬병 생독백신 접종이 의무화되어 있어 부화장에서 병아리 분양 시 분무백신기를 이용한 닭 뉴캣슬병 생독백신을 접종하게 되고, 또한 농장에서 닭 뉴캣슬병 추가백신 접종이나 닭 전염성 기관지염 백신 접종 시에도 분무접종을 실시하기도 하는 등 분무접종에 대한 경험은 누구나 가지고 있을 것이다. 그러나 음수접종법과 달리 분무접종 시 심한 백신접종반응을 경험하게 되는 양계인들도 쉽게 만나볼 수 있다. 생독백신은 음수접종법을 비롯하여 점안접종법 및 분무접종법 등 다양한 접종방법이 현재 야외농장에서 응용되고 있으며, 국내 육계사육 시에는 음수접종법과 분무접종법이 주로 사용되고 있다. 하지만 동일한 종류의 생독백신이라 할지라도 백선접종방법에 따라 백신접종 후 백신접종효능뿐만 아나라 백신접종반응에도 많은 차이를 보이게 되며 동일한 분무접종법이라 하더라도 어떠한 입자 크기의 분무기를 사용했는가에 따라서도 이러한 차이는 있다. 분무접종은 백신 바이러스가 비강，눈(harderian gland) 뿐만 아니라 상부 호흡기도에 직접적으로 작용을 하여 강력함 국소면역능을 유발하는 장점을 가지고 있으나 접종일령이나 접종 백신의 종류를 고려한 분무입자 크기의 선택이 제대로 이루어지지 않아 음수접종법에 비해 접종 부작용이 크게 나타나는 백신접종법으로 인식되어 있는 실정이다. 따라서 이번 호에서는 호흡기 질병의 예방 백신 분무접종에 대해 알아보고자 한다.

• KOREAN POULTRY JOURNAL
• /
• v.36 no.5 s.415
• /
• pp.115-119
• /
• 2004

최근 야외에서 ND가 간간히 발생하고 있다는 소식이 들려오고 있다. 우리나라의 경우 ND 발생의 경우 독특한 양상을 띠고 있다. 첫째는 $2\~3$년의 주기로 발생이 되고 있으며 둘째는 $4\~6$월 사이에 발생이 집중 된다는 점이다. 고병원성 가금 인플루엔자(HPAI)를 겪은 우리에게 혹 긴장감이 느슨해지면서 농장의 차단 방역과 방역에 소홀해짐으로 올 봄 ND 대유행의 홍역을 치르는 것은 아닌지 다시 한번 경각심을 가져 보게 되면서 농장에서 관심을 갖고 있는 ND 분무 접종에 대해 이야기해보고자 한다. $5\~6$년 전까지만 해도 분무 백신에 대한 관심이 별로 없었던 게 사실이다. 그전 같았으면 음수 백신으로 백신 방법을 대치하고 말았을 것을 분무 백신을 해야 하는지? 또 어떻게 해야 하는지? 주의해야 할 점은 무엇인지? 등 여러 가지 질문을 받게 된다. 농장 부화장으로부터 분무기에 대한 관심도 부쩍 높아졌고, 이제는 대부분의 농가들이 분무 백신의 효능과 안전성에 대해 확신을 갖고서 꾸준히 실시하고 있는 것을 알 수가 있다. 대부분 많은 시행착오를 거쳐 나름대로의 기술력을 갖추게 되었고 많은 효과를 보고 있다고 말할 수가 있다. 그러나 아직 일부 농가들은 분무 백신 후 방어력과 후유증 즉, 안전성에 대해 많은 의심을 갖고 있으면서 시간과 노동력이 많이 소요되는 점안 백신을 하는 경우도 종종 보고있다. 이에 수년간의 경험을 통해 필자가 보는 견지에서 분무 백신을 하는데 있어 여러 가지 고려해야 할 사항, 주의 사항, 효과를 최대한 높이기 위한 방법 등을 알아보고자 한다.