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Yangyang, South Korea

Kim Y.-D.,South Korean National Fisheries Research and Development Institute | Hong J.-P.,Korea Fisheries Resources Agency | Song H.-L.,South Korean National Fisheries Research and Development Institute | Park M.S.,South Korean National Fisheries Research and Development Institute | And 2 more authors.
Journal of Environmental Biology | Year: 2012

We installed seaweed reef for restoration of barron ground coast. We hollowed out a U-shaped groove in a cross-shaped artificial seaweed reef and covered it with a zinc sheet (U-bar) to transplant Ecklonia cava growing on Dellenia wood by hand, installing the U-bar on the artificial seaweed reef, fixing it with concrete. Thus seaweed can be attached easily, with pre-installed stainless bolts and nuts. The length of Ecklonia cava leaf transplanted to the cross-shaped reef was 7.2 cm in February 2005 reached its maximum size, 35.9 cm (n=30) by July. Thereafter, it decreased to 18.9 cm in October due to shedding. The leaf weight after the experiment was 24.8 from the initial 0.4 cm (n=30). Regression analysis showed Y=0.78757X4.6488 (R2=0.7225) for blade length and Y=0.0025X26733 (R2=0.8711) for leaf weight. The high values of the R2 values for the two measurements were highly reliable, with the reliability of the linear regression function higher than thatof the functions of 2 variables. The artificial seaweed forest constructed in the barren ground was highly comparable with natural seaweed forest in terms of growth, indicating that the artificial seaweed construction can be done in an easy, efficient and economically viable way. This further indicates that the technology developed by the present study can be extensively used for the project for artificial seaweed forest construction. © Triveni Enterprises. Source

Han H.-S.,South Korean National Fisheries Research and Development Institute | Taniguchi N.,Fukuyama University | Lee J.-H.,South Korean National Fisheries Research and Development Institute | Yoon M.,Korea Fisheries Resources Agency
Fisheries and Aquatic Science | Year: 2012

We investigated the genetic structure of Korean and Japanese ayu Plecoglossus altivelis populations by examining 669 individuals from 14 populations using three microsatellite loci. Genetic variation did not differ significantly among the populations examined in terms of allelic number and heterozygosity. Korean populations were genetically close to each other, implying that persistent gene flow has occurred in these populations. This suggests that eastern populations in Korea form a single large population and all of the Korean populations are distinct from the Japanese populations. Pairwise population FST estimates, principal component analyses, and a neighbor-joining tree showed that genetic separation between the southern and pooled eastern coast populations was probably influenced by restricted gene flow. Hierarchical analysis of molecular variance (AMOVA) revealed a weak but significant genetic structure among three ayu groups (eastern and southern coasts of Korea and the Japan coast), and no genetic variation within groups. The estimated genetic population structure and potential applications of microsatellite markers may aid in the proper management of ayu populations. © The Korean Society of Fisheries and Aquatic Science. Source

Yoon J.T.,Korea Fisheries Resources Agency | Sun S.M.,Chonnam National University | Chung G.,Chonnam National University
Journal of Applied Phycology | Year: 2014

Studies on the construction of artificial seaweed beds were carried out for the restoration of barren grounds that extend along the coast of Jeju Island in Korea. Fertilized eggs of Sargassum fulvellum and Sargassum horneri were induced from receptacles of mature plants and adhered to concrete block substrata. When the germlings that settled on the artificial substrata had grown to 3-5 mm in indoor cultures, they were moved to the ocean for intermediate cultivation, where they were cultivated under seed-cultivating nets to prevent damage from grazing animals. After the germlings had grown to 25-50 cm, the artificial substrata with settled germlings were taken out from the protective cage and transplanted on the barren grounds along the coast of Jeju Island. In the early stage of transplanting, the Sargassum thalli were partially eaten by grazing animals. Two months post-transplantation, the plants grew quickly, and their stems were harder and free from grazing damage. Most of the Sargassum had grown to over 300 cm by 6 months after transplantation on the barren grounds, and they were forming a marine forest community at the transplant sites. © 2013 Springer Science+Business Media Dordrecht. Source

Han H.-S.,South Korean National Fisheries Research and Development Institute | Nam B.-H.,Biotechnology Research Center | Kang J.-H.,Biotechnology Research Center | Kim Y.-K.,Biotechnology Research Center | And 3 more authors.
Fisheries and Aquatic Science | Year: 2012

We used nine microsatellite DNA markers to estimate genetic variation among wild and cultured populations of the sea squirt Halocynthia roretzi. The loci were polymorphic, with 6-32 alleles, and allelic richness ranged from 6.0 to 26.1 in each population. The wild and the cultured populations had similar mean heterozygosities (H O and H E), allele numbers, and allelic richness. One cultured population with softness syndrome had a lower mean in the observed heterozygosity (H O = 0.57) and higher mean inbreeding coefficient (F IS = 0.261) than any other populations. This suggests that the loss of genetic variation in the diseased population might be due to increased inbreeding. A neighbor-joining tree and pairwise population estimates of F ST showed moderate genetic differentiation between the wild and the cultured populations. Additionally, the softness syndrome population was genetically divergent from wild populations, but it was genetically close to the cultured populations. © The Korean Society of Fisheries and Aquatic Science. Source

Choi H.J.,South Korean National Fisheries Research and Development Institute | Hwang J.Y.,South Korean National Fisheries Research and Development Institute | Choi D.L.,Korea Fisheries Resources Agency | Huh M.D.,Pukyong National University | Park M.A.,South Korean National Fisheries Research and Development Institute
Journal of Invertebrate Pathology | Year: 2012

The eggs of the Pacific oyster, Crassostraea gigas, become infertile when infected by the parasite Marteilioides chungmuensis. Histologically, M. chungmuensis infects the oyster oocyte cytoplasm, and the ovaries take on a "lumpy" appearance once infected, which lowers commercial value of the oyster. This has a negative economic impact on oyster farms in South Korea and Japan. In this study, we compared traditional diagnostic methods (histology) with two molecular-based methods (polymerase chain reaction [PCR] amplification and in situ hybridization [ISH]) to identify M. chungmuensis-infected oysters. The efficacy of PCR and ISH to identify M. chungmuensis-infected oysters was compared to that of routine histology in 100 oysters. Thirty infections were identified using PCR and 16 using histology, whereas 31 infections were identified using ISH. The ISH and PCR assays were more sensitive compared to using histology with standard epidemiological methods. We strongly recommend that early parasitic invasion should be monitored with PCR/ISH methodologies as a basis for developing effective diagnostic techniques to identify M. chungmuensis-infected oysters. © 2012 Elsevier Inc. Source

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