• Environmental Analysis Health and Toxicology
• /
• v.24 no.1
• /
• pp.17-23
• /
• 2009

Nanotechnology, one of the technologies that forms the core of the recent scientific innovation, is used much in our real lives. Especially products that use nano silver are being sold, with its positive characteristics resulting from the antibacterial effects of both nano materials and silver. But critiques have pointed out that nano silver diffused into everyday life too quickly as we do not have done any comprehensive research about the material, and worry that nano silver will affect the ecology adversely. Therefore, this research focuses on investigating the toxicity of silver nanoparticles first. To compare the effects of exposure to silver nanoparticles at pre-somite stage and somite stage(10 hours after fertilization), we exposed zebrafish embryos to silver nanoparticles(15, 30 ppt) during embryogenesis, and then checked the details of catalase enzyme activity. The hatch rate decreased in the silver nanoparticles exposed groups(15 and 30 ppt); furthermore, the hatched fishes had an abnormal notochord, damaged eyes and curved tail. The catalase activities of the 15 ppt exposed group at somite stage increased relative to those in the control group. Therefore, the silver nanoparticles could seriously damage the development of zebrafish embryos. Especially, exposure to silver nanoparticles at somite stage did severer damage than exposure since pre-somite stage did.

• Korean Journal of Ichthyology
• /
• v.12 no.2
• /
• pp.146-153
• /
• 2000

The development of larvae and juvenile of the smoothskin sculpin (Ocynectes modestus) caught at Pusan brook in May and June 1995 was described. Yolk was completely absorbed when the larvae was about 6.28 mm in average standard length (ASL) with 32~33 myomeres. Flexion of the notochord started when the juvenile was about 7.36 mm in ASL and finished about 9.34 mm in ASL, respectively. Aggregate numbers of all fin rays were completed at over 10.08 mm in ASL, when the larvae reached the juvenile stage. One pairs of flaps were observed on the dorsal surface of the head at 10.08 mm in ASL. The juveniles longer then 14.00 mm in ASL has the same pigment pattern as that of adults. A new Korean name "Min-Ga-Si-Ggeog-Jeong-i" is proposed for this species.

• Korean Journal of Ichthyology
• /
• v.8 no.2
• /
• pp.1-9
• /
• 1996

Egg and larval stages of the rockfish, Sebastes thompsoni and S. pachycephalus pachycephalus, are described and illustrared. The size of these eggs when released were 1.27~1.33mm in S. thompsoni and 1.39~1.52mm in S. pachycephalus pachycephalus. The size of these hatching larvae when released were 3.02~3.12mm TL (total length) in S. thompsoni and 4.83~5.17mm in S. pachycephalus pachycephalus. Notochord flexion occured 7.56~8.00mm TL (17~20 days after hatching) in S. thompsorzi and 5.43~5.56mm in S. pachycephalus pachycephalus. Preflexion and flexion larvae (averaged 3.97~7.78mm TL) of S. thompsoni were distinguished from related species by pigmentation of the dorsal and ventral midlines of the tail. Larvae of S. pachycephalus pachycephalus were distinguished from related species by pigmentation of the dorsal and ventral midlines of the trunk. Transformation occured 14.22~15.86mm TL in S. pachycephalus pachycephalus.

• Korean Journal of Ecology and Environment
• /
• v.41 no.1
• /
• pp.104-110
• /
• 2008

The egg development and early life history of Korean endangered natural monument fish, Iksookimia choii, were investigated in 2006. The eggs from the females were obtained by injecting 10 IU $g^{-1}$ of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were $1.1\sim1.3mm$ in diameter and had no oil globules. Hatching of the embryo began about 24 hrs after fertilization under water temperature of $25^{\circ}C$. The newly-hatched larvae were $2.5\sim2.7mm$ in total length (TL), and their mouth and anus were not yet opened. Six days after hatching, the postlarvae were $4.7\sim5.4mm$ TL, and tip of the caudal notochord was flexed $45^{\circ}$ upward. The juveniles stage was reached when all fin-rays were formed at 35 days after hatching, and their total length were $20\sim22mm$.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.57 no.2
• /
• pp.134-148
• /
• 2021

During the ichthyoplankton survey around the Chilsan Island (previously known as the biggest spawning ground of the Sciaenidae) in the southwestern sea of Korea from April to June in 2019 using ring nets, we collected a total of 12 individuals belonging to the family Sciaenidae. Using molecular methods, we identified five sciaenid species (Collichthys lucidus, Collichthys niveatus, Johnius grypotus, Nibea albiflora, and Pennahia argentata), and described and compared them on the basis of the preflexion larval stage. C. lucidus was well distinguished by the presence of occipital crests at preflexion stage. Although there were no occipital crests, preflexion larva of C. niveatus was distinguished by the absence of melanophore except for the upper part of the abdominal cavity. J. grypotus and N. albiflora were very similar morphologically, but were distinguished by myomere height (15.22-15.53% in J. grypotus vs. 11.66-12.78% in N. albiflora) in the percentage of notochord length, and eye diameter (32.58-33.37% in J. grypotus vs. 40.32-42.53% in N. albiflora) in the percentage of head length between specimens of similar size (J. grypotus: 3.22-3.23 mm, N. albiflora: 3.04-3.13 mm). P. argentata were distinguished by distribution of ventral caudal melanophore (one row of small spot in P. argentata vs. irregular patches on the central part of caudal in J. grypotus and N. albiflora). Comparative morphological studies using more diverse species must be conducted for more comprehensive understanding of the morphogenesis of Sciaenidae.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.2
• /
• pp.228-242
• /
• 2023

We examined the osteological development of the cranium, visceral skeleton, pectoral girdle, vertebral column, fins, and pterygiophore of small yellow croaker Larimichthys polyactis cultured at the Jeju Fisheries Research Institute. At 5.89 mm NL (notochord length), the larvae already had ossified frontal and basioccipital bones, parasphenoids, and vomer in the cranium. All elements of the visceral skeleton except the metapterygoid were ossified at 5.89 mm NL. Preorbital bone was ossified at 8.11 mm SL (standard length), and suborbital bones were ossified at 12.90 mm SL. In the vertebral column, ossification proceeded from the first to last centrum. The urostyle ossified at 7.41 mm SL. The caudal skeleton ossified at 6.78 mm NL, along with three hypural bones. In the pectoral girdle, the cleithrum, supracleithrum, postcleithrum, and post-temporal bones ossified at 5.89 mm NL. Caudal fin ossification began at 6.19 mm SL and was complete at 7.16 mm SL. Dorsal and anal fin ossification began at 7.16 mm SL and was complete at 8.62 mm and 8.11 mm SL, respectively. Anal and dorsal pterygiophore bone ossification was complete at 9.86 mm and 11.54 mm SL, respectively, and that of the supraneural bones was complete at 9.60 mm SL.

• Korean Journal of Ichthyology
• /
• v.35 no.1
• /
• pp.1-9
• /
• 2023

The morphological development of larvae and juvenile of Sebastes taczanowskii were studied. The S. taczanowskii were caught at Goseong-gun, Gangwon-do from March in 2016. Larvae beared at water temperature of 11~12℃ (mean 11.5±0.5℃). The just beared larvae were 5.25~5.96 mm (mean 5.60±0.19 mm, n=30) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postlarvae stage. 35 days after bearing postlarvae was measured 7.16~11.4 mm (mean 9.02±1.00 mm) in total length and the tip of notochord was bent upward. 48 days after bearing juvenile was measured 9.45~18.7 mm (mean 14.4±1.75 mm) in total length with dorsal fin rays XIII, 13~15; anal fin rays III, 6~8; caudal fin rays 16.

• Journal of the Korean Society of Radiology
• /
• v.81 no.4
• /
• pp.979-984
• /
• 2020

Cri-du-chat syndrome is a rare genetic disorder in which the patient presents with a characteristic high-pitched monotonous cry and recurrent aspiration pneumonia, attributed to abnormalities in the larynx, epiglottis, and nervous system. The most prominent brain MRI findings are the presence of pontine and cerebellar hypoplasia, which primarily involve posterior cranial fossa structures. Although atrophy of supratentorial structures were also a common radiological finding, it was considered to be a secondary change due to pontine hypoplasia. Here, we present the case of a three-month-old patient presenting with cri-du-chat at our institution. The patient also showed the presence of prominent pontine hypoplasia similar to previously reported cases; however, contrary to other cases, there was a general delayed myelination of brain instead of decreased myelination of anterior limb of internal capsule. Since the larynx, pons, and cerebellum all originated from similar notochord level, which suggests anomaly in early stage of development, laryngeal, and brain anomaly characteristically observed in the cridu-chat syndrome.

• Korean Journal of Ichthyology
• /
• v.31 no.1
• /
• pp.7-15
• /
• 2019

The present study aimed to investigate the influence of starvation on growth, survival and swimming ability of Pacific cod Gadus macrocephalus larvae. Notochord length, musculature height, body depth, gut height and volume of yolk of reared larvae were measured to determine the growth parameters. A significant difference was observed in all morphometric characteristics before 15 DAH (days after hatching). Body depth and volume of yolk of unfed larvae were significantly smaller than those of fed larvae from 9 DAH (P<0.05). Almost all yolk in fed group was consumed at 11 DAH. Survival and growth of larvae were observed to determine the effect of delayed initial feeding (2 DAH, 3 DAH, 4 DAH, unfed). All larvae in the unfed group died by 15 DAH and the larvae in other experimental groups survived until the end of the experiment to 21 DAH. Survival rate was not significantly different between the 2 DAH group ($17.5{\pm}4.27%$) and the 3 DAH group ($20.5{\pm}1.5%$) at 21 DAH (P>0.05). However, there was a significant difference in survival rate between the 3 DAH group and the 4 DAH group ($11.7{\pm}1.52%$) (P<0.05). There was no significant difference in notochord length among the groups fed from 2 DAH, 3 DAH and 4 DAH at 21 DAH (P>0.05). The swimming ability in fed group gradually increased in both cruising and burst swimming speeds, while those abilities in unfed group gradually decreased after reaching the peak at 6 DAH in both cruise ($18.7{\pm}6.56mm/s$) and burst swimming speed ($43.5{\pm}12.65mm/s$).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.26 no.5
• /
• pp.465-476
• /
• 1993

Rockfish, Sebastes inermis is a ovoviviparous fish distributed around the coastal waters of Korea and Japan. Naturally beared larvae obtained from female fish kept in the aquarium were reared for three months in the laboratory. The naturally healed larvae were 6.05mm in average total length(TL) with $8+18{\sim}19=26{\sim}27$ myomeres. Melanophores were distributed on the top of head, around the intestine tube and on the dorsal and ventral margins of the tail, but none on the pectoral fins. The larva(7.1mm in TL) consumed all the yolk and oil globule, in 7 days after bearing, and jaw bones were more rapidly ossified than vertebrae and cranium. In 21 days after bearing, the larvae averaged 8.50mm in TL and the caudal notochord flex $45^{\circ}$. Fin development in S. inermis larvae proceeds in the following sequence: caudal, pectoral, dorsal, anal and ventral fin. Individuals $17.6{\sim}20.8mm$ in TL($65{\sim}69$ days after bearing) are regarded as the juvenile stage. All fins bones was nearly completed in this stage.