• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.753-758
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• 2011

The seawater adaptability of land-locked masu salmon Oncorhynchus masou masou via acclimation was examined for aquaculture purposes. The survival, blood chemistry, and histological changes of masu salmon (150 g) were measured after 7-, 15-, and 30-day acclimation periods. After a total of 60 days in seawater cultures that incorporated the various acclimation periods, survival was 83.5, 87.2, and 91.0% for the 7-, 15-, and 30-day periods, respectively; thus, survival increased with longer periods of acclimation. Feeding efficiencies were 32.1, 52.0, and 40.6% for the 7-, 15-, and 30-day periods, and specific growth rates were 0.14, 0.26, and 0.23%, respectively. Generally, masu salmon appeared to exhibit better growth performance after an acclimation period of 15 days. Cortisol concentrations [mean ${\pm}$ SD] for 7, 15, and 30 days of acclimation were $21.0{\pm}6.5$, $17.8{\pm}4.8$, and $21.2{\pm}5.4\;{\mu}g/dl$, with the lowest values occurring with 15 days of acclimation. Osmolarities were $359.2{\pm}26.1$, $350.4{\pm}29.2$, and $354.6{\pm}29.3$ mOsm/kg, and glucose concentrations were $60.7{\pm}20.7$, $72.9{\pm}17.3$, and $76.6{\pm}14.1$ mg/dl for the 7-, 15-, and 30-day acclimation periods, respectively (P < 0.05). The histological study revealed that both gills and both kidneys of the masu salmon exhibited middle- to end-stage and middle-stage lesions in the 7- and 15-day groups, respectively, whereas these organs only had early-stage lesions in the 30-day group in the final experiment. Therefore, the seawater acclimation of masu salmon should involve more than 30 days in seawater.

• Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.36-40
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• 2008

We analyzed the nucleotide sequences of about 500 bp of the mitochondrial NADH dehydrogenase subunit 3 (ND3) gene to estimate the genetic variation of Korean masu salmon (Oncorhynchus masou) populations. DNA samples were collected from 104 river-only specimens and 52 anadromous specimens from three hatcheries and one river. There are no records of artificial release into the river. We amplified the ND3 gene by polymerase chain reaction, targeting areas that included parts of the cytochrome oxidase III gene and the NADH dehydrogenase subunit 4L gene, and defined 14 haplotypes based on 12 variable nucleotide sites in the examined region. Among the haplotypes, ten were specific to river-only specimens within hatchery populations. Haplotype diversity of river-only populations in hatcheries was higher than that of anadromous and wild populations. Pairwise population $F_{ST}$ estimates and neighbor-joining tree analyses inferred that anadromous and river-only populations were distinct. These results suggest that sequence polymorphism in the ND3 region may be a useful marker for analyzing the genetic variation and population structure of masu salmon.

• Development and Reproduction
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• v.24 no.3
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• pp.241-248
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• 2020

This study used a PCR-based genetic analysis platform to create a hierarchical polar dendrogram of Euclidean genetic distances for two salmonid species, Oncorhynchus mykiss (rainbow trout, RT) and Oncorhynchus masou (masu salmon, MS). The species were distantly related to other fish species based on PCR results from using the designed oligonucleotide primer series. Five oligonucleotide primers were used to generate 330 and 234 scorable fragments in the RT and MS populations, respectively. The DNA fragments ranged in size from approximately 50 bp to more than 2,000 bp. The bandsharing (BS) results showed that the RT population had a higher average BS value (0.852) than that for the MS population (0.704). The genetic distance between individuals supported the presence of adjacent affiliation in cluster I (RT 01-RT 11). The observation of a significant genetic distance between the two Oncorhynchus species verifies that this PCR-based technique can be a useful approach for individual- and population-based biological DNA investigations. The results of this type of investigation can be useful for species safekeeping and the maintenance of salmonid populations in the mountain streams of Korea.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.833-840
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• 2003

Sperm motility of salmonid fishes is suppressed by external $K^{+}$ and initiated by decrease of $K^{+}$ concentration surrounding the sperm. It was shown that the decrease in external $K^{+}$ concentration induced not only the initiation of sperm motility, but also hyperpolarization of the plasma membrane and synthesis of cAMP in the sperm of rainbow trout, steelhead trout, and masu salmon. Inhibitors of $K^{+}$ channels, especially voltage-dependent $K^{+}$ channels, inhibited these three reactions, and the inhibitions were abolished by subsequent addition of a $K^{+}$ ionophore, valinomycin, suggesting that $K^{+}$ efflux through the $K^{+}$ channel contributes to rapid changes in the membrane potential of sperm and cAMP synthesis, thereby resulting in the initiation of sperm motility of salmonid fishes.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.311-321
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• 2009

Three categories (freshwater, amphidromous, and marine fishes) of Taiwanese fishes are analyzed on the basis of zoogeographic elements, viz. China element, Indo-China element, Indo-West Pacific element, Indo-Pacific element, North-Pacific element, Japan-Oregon element, and circumtropical element. Freshwater fishes, which include the China and Indo-China elements, are distributed on part of the boundary area between the Palaearctic and Oriental regions of Wallace (1876). Diadromous fishes include the North-Pacific, Indo-China and Indo-West Pacific elements. Taiwanese salmon, a landlocked (initially diadromous) species that became established in Taiwan between 0.5 my B.P. and the early Pleistocene, is recognized as a distinct taxon included within the Oncorhynchus masou complex, which comprises here three species and two subspecies, viz. Oncorhynchus masou masou (Sancheoneo, Songeo, Sakura-masu or Yamame), O. masou ishikawae (Satsuki-masu or Amago), O. sp. (Biwa-masu), and O. formosanus (Taiwanese salmon), based on molecular, morphological and biological studies. Marine fishes are discussed under the following headings, brackish-water fishes (fishes of brackish waters and seas adjacent to continental coastlines, North Pacific and Indo-West Pacific elements; fishes of brackish waters and seas primarily around islands, Indo-West Pacific element), reef fishes (fishes of inshore reefs along continental coastlines from 0 to ca.100 m depth, Indo-West Pacific element; fishes of inshore reefs primarily around islands from 0 to ca.100 m depth, Indo-West Pacific element; fishes of offshore reefs along continental shelf edges from ca.150 to 300 m depth, circumtropical and Indo-Pacific elements; fishes of offshore reefs primarily around islands from ca.150 to 300 m depth, Indo-Pacific element), demersal fishes (fishes on continental shelves shallower than ca.150 m depth, Indo-West Pacific and Japan-Oregon elements; fishes on edges and upper continental slopes from ca.150 m to 500 m depth, Indo-West Pacific, Indo-Pacific, and circumtropical elements; fishes on lower continental slopes to abyssal plains from ca.500 m to 6,000 m depth, circumtropical element and rarely Indo-Pacific element), pelagic fishes (epipelagic fishes from 0 to ca.150 m depth, Indo-West Pacific, Indo-Pacific or circumtropical elements; meso- and bathypelagic fishes from ca.150 to 3,000 m depth, circumtropical element). The distribution of Taiwanese marine fishes are influenced by the Kuroshio Current, low-salinity and low-temperature waters from mainland China, and sea-bottom topography.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.208-229
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• 1996

Comprative osteology of the chum salmon Oncorhynchus keta, masu salmon O. masou and rainbow trout O. mykiss in Korea was studied. As a result, it was found that there were some differences in the structural features of the cranium and visceral skeleton among the species. Interspecific differencies in glossohyal, supraethmoid, parasphenoid and vomer were distinctive for the species. Chum salmon could be distinguished easily by some characters on form of glossohyal which is thin, long and sharp in shape. It has triangle shape supraethmoid while other two species have oval shape one. The shape of parasphenoid, preopercle, hyomandibular and the number of epurals were evaluated as new taxonomic criteria for the salmons.

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.203-204
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• 2004

• Water Engineering Research
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• v.6 no.4
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• pp.149-159
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• 2005

With increasing recognition on conservation of endangered species in Taiwan, one of the major conservation projects is the habitat restoration of Formosan Landlocked Salmon which is major threatened by check dams in the channel for their blockading pathway to upstream and causing the problems of population isolation and close-blood mating. By creating an opening in the central dam body appropriately, partial removal dams can provide pathway for the fish for the better upstream channel habitat. Four check dams at Gau-Shan Creek were remodeled between April of 1999 and September of 2002 with information supported from model experiments under certain hydraulic condition of field environment. Based on the follow-up investigation, the channel morphology of observation sections is in stable condition and the total number of Formosan Landlocked Salmon in this creek increased promptly at the reach containing partial-removed dams.

• Journal of fish pathology
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• v.23 no.3
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• pp.421-427
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• 2010

Anisakid nematodes third stage larvae were isolated from the muscles of masou salmon (Oncorhynchus masou). Fish were purchased from Jumunjin fishery market in Gangneung. Four Anisakid third stage larvae were isolated from 4 fish. Molecular identification of the isolated worms was conducted by PCR-RFLP analysis of ribosomal DNA internal transcribed spacer region and direct sequencing of mitochondrial DNA cox2 gene. As results, all the tested individual worms were identified as Anisakis simplex (sensu stricto). This is the first report of molecular detection of anisakid worms in salmonid fishes in Korea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.86-93
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• 2007

We analyzed the aquatic insects and stomach contents of chum salmon (Oncorhynchus keta) fingerings which were collected at Namdae stream in Yangyang. A total of 6 orders, 25 family, and 52 species of aquatic insects have been found in the study area. The majority of prey eaten by chum salmon fingerlings was Diptera, which occupied 91.7% of prey items by number and 40.9% by wet weight. The food items from juvenile salmon stomachs were matched with living organisms in the river. Therefore it seemed that there was no food selectivity of juvenile chum salmon in Namdae stream. The stomach contents of masu salmon fry showed a similar pattern to the fingerlings of chum salmon. This result will provide information on the carrying capacity of Namdae stream for chum salmon.