• Title/Summary/Keyword: 치어

Search Result 475, Processing Time 0.058 seconds

Morphology of a Larval Hammerjaw Omosudis lowii Gunther 1887 (Aulopiformes, Omosudidae) Identified by Partial Mitochondrial 12S rRNA Gene Analysis (12S rRNA로 동정한 홍메치목 Omosudis lowii 치어의 형태적 특징)

  • Choi, Hae-young;Jang, Yo-Soon;Oh, Ji-na;Kim, Sung
    • Korean Journal of Ichthyology
    • /
    • v.32 no.4
    • /
    • pp.239-244
    • /
    • 2020

  • The morphological characteristics of a larval fish (7.8 mm in body length) collected off Chuuk, Micronesia were highly similar to those of larval Omosudis sp., except fin development and body length. It was identified as Omosudis lowii by partial mitochondrial 12S rRNA gene analysis. The morphological traits of the larval fish validated by the molecular genetic marker will be informative for species-level identification of larval Omosudis lowii.

  • https://doi.org/10.35399/ISK.32.4.5 인용 PDF KSCI

Quantitative analysis of the clinical signs in marine fish induced by Megalocytivirus infection (Megalocytivirus 감염 해산 어류에서 나타나는 임상증상의 정량적 변화 분석)

  • Jin, Ji-Woong;Cho, Hye-Jin;Kim, Kwang-Il;Jeong, Joon-Bum;Park, Gyeong-Hyun;Jeong, Hyun-Do
    • Journal of fish pathology
    • /
    • v.24 no.2
    • /
    • pp.53-64
    • /
    • 2011

  • In quantitative studies of clinical signs, rock bream of adults and juveniles infected with Megalocytivirus IVS-1 isolated from rock bream (Oplegnathus fasciatus) in Korea showed average $4.49{\pm}1.13$ and $4.85{\pm}1.06$ of spleen index respectively. In challenge experiments, Megalocytivirus IVS-1 induced 100% cumulative mortality in both adult and juvenile rock bream. However we found 60% cumulative mortality in juvenile red sea bream (Pagrus major) even after 30 days of injection, which contradicted with the results of other laboratories. Interestingly, IVS-1 infected red sea bream of the same juvenile size with rock bream showed lower spleen index compared to that of rock bream. In real-time PCR, there was continuous increasing of the numbers of viral copies ($2.03{\times}10^7$ copies/mg) in the spleen of juvenile rock bream infected, which were different from those in adult rock bream showing plateau level after reaching to the peak level. Moreover, enlarged cell numbers in the infected spleen were also increased continuously in the juvenile but not in adult of rock bream, even decreased after reaching to peak level. Consequently, significant differences in clinical signs: cumulative mortality. spleen index and viral copy number were found between rock bream and red sea bream, but not between adult and juvenile rock bream. Certainly quantitative expression of clinical sign as in this study may be a way to compare the progression of megalocitiviral disease more accurately in different species or physiological conditions.

  • https://doi.org/10.7847/jfp.2011.24.2.053 인용 PDF KSCI

Monitoring the Growth of Juvenile Chum Salmon (Oncorhynchus keta) Released to Taehwa River of Korea (태화강 내 연어(Oncorhynchus keta) 치어의 방류에 따른 성장 모니터링)

  • Hur, Jun Wook;Yoon, Ji Woo;Lim, Han Kyu
    • Journal of Marine Life Science
    • /
    • v.6 no.2
    • /
    • pp.106-116
    • /
    • 2021

  • To secure basic data by monitoring the growth of salmon (Oncorhynchus keta) released to the Taehwa River. After discharge, the characteristics of the young salmon distribution and migration rate habitat were investigated for two years. A total of 4 points [Sunbawi bridge (St.1), Guyeong bridge (St.2), Samho bridge (St.3), and Myeongchon bridge (St.4)] were investigated. The survey of 2017 indicating an increase of 10 mm in average length and 0.8 g in average weight, and the survey of 2018 indicating an increase of 10 mm in average length and 0.5 g in average weight. Among 39 species, 10 insectivorous and 12 omnivorous, are believed to compete with young salmon for food. 6, 5, 6 and 8 predatory fish species has emerged at each site, respectively. According to this study, it is believed that St.1 and St.2 points are more proper as discharge location of young salmon because these two points have less varied in depth, flow rate, salt concentration etc. In addition, it is thought that the night or dawn time in early January is the best discharge time of young salmon fish because predatory fish such as Korean piscivorous chub and bass etc. does not eat food actively at that time.

  • https://doi.org/10.23005/ksmls.2021.6.2.106 인용 PDF KSCI

The Relationship Between Environmental Conditions and Growth of Chum Salmon Fingerlings (사육환경과 연어치어 성장과의 관계에 관한 연구)

  • Seong, Ki-Baik;Kim, Ju-Kyung
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.12 no.2
    • /
    • pp.81-85
    • /
    • 2007

  • Early growth of chum salmon was investigated in terms of rearing pond condition. The number of fingerling showed big differences by rearing pond $1,003,000{\sim}1,865,000$. The fork length of fingerlings ranged from $3.20{\sim}3.78cm$ and body weight ranged $0.34{\sim}0.49g$. Daily temperature of rearing water in January to March was $6{\sim}8^{\circ}C$, which is inadequate for salmon growth. pH was $6.0{\sim}6.3$ in early and mid February, 6.5 in late February and $6.5{\sim}7.0$ in March. Dissolved oxygen concentration was lowest from 8 a.m. to 6 p.m. and increased after 6 p.m. The maximum value was seen from 9 p.m. to 6 a.m. The mortality of fingerlings was 5 times higher in the daytime than at night because of dissolved oxygen. Growth of fingerlings was affected by daily ration, concentration of dissolved oxygen and rearing temperature.

  • https://doi.org/10.7850/jkso.2007.12.2.081 인용 PDF KSCI