• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.273-277
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• 2021

The feeding habits of the pointhead flounder, Cleisthenes pinetorum were studied in the West Sea in Korea. The samples were investigated using 360 specimens (21.7~48.1 cm in total length) collected by gill net of the coastal waters from January to December 2019. As a result, C. pinetorum consumed mainly Ophiuroidea and Pisces, but also ate small amounts of Macrura, Echinodermata, Amphipoda and Brachyura. The results of this study showed a difference with those of main feed habits of C. pinetorum caught in the coastal waters of Kori (Huh and Baeck, 2003). The proportion of fishes in prey items increased with size-related while that of Ophiuroidea decreased. As total length of C. pinetorum increased the mean number of preys per stomach (mN/ST) and weight of prey per stomach (mW/ST) tended to increase.

• The Journal of Fisheries Business Administration
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• v.54 no.3
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• pp.69-92
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• 2023

The 'Japanese Useful Fisheries Classification Table', published in advance before the publication of the "Useful Fisheries of Japan", is the first data to classify and introduce fisheries animals and plants in a single table. Therefore, it had received public attention immediately. However, The academy of animal studies at that time quickly pointed out that this classification table was a mixture of traditional and modern classifications, and that there were too many errors. However, Yoshio Tanaka, who was in charge of revising Yamamoto Arikatana, that wrote the classification table, was not an adherent of traditional taxonomy, nor was he ignorant of modern taxonomy. Nevertheless, the classification table, which was quite different from the well-known zoological classification at that time, was prepared. For example, the top classifications of marine organism are not at the same level, but rather a mixture of phylum and class, while the water insect contains several phylums, including Arthropoda, Echinodermata, Mollusca, and Coelenterata. As such, the method of classification of animals in the classification table was hard to understand in the zoological academy at that time. The reason for this unusual taxonomy was that the classification table showed classification of useful fisheries products, not intended to convey academic classification. In other words, it is not for the purpose of academic classification of all fishery products, but for the purpose of presenting standards that can be easily understood by those engaged in the collection, manufacture, and aquaculture of fishery products. This principle of 'Useful Fisheries of Japan' is also ascertained in the "Fishing Methods of Japan" and "Fishery Products of Japan". Regarding the collection and processing of marine products, it could have shown how to catch whales, which are mammals, and how to dismantle whales and obtain oil and meat, according to academic classifications. However, the first appearances in the book include dried squid, abalone, shark fins, and sea cucumbers. In other words, the most important fishery products at that time are presented first. The contents of the classification table, which is considered somewhat bizarre, show where the purpose to compile Useful Fisheries of Japan.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.313-324
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• 2023

Species composition and seasonal variation of aquatic organism were collected by pot and trammel net in the coastal waters of Taean in 2018. A total of 4,501 individuals belonging to 78 species were collected in two type of gears. The dominant species in the study area was Strongylocentrotus nudus (Echinodermata). In the pot survey, crustaceans were the most common taxa, with 52 species including Palaemon gravieri, whereas fish were dominant in trammel net with 57 species including Okamejei kenojei. Clustering analysis revealed two distinct groups, indicating that the composition of aquatic organism varies according to oceanographic condition and environmental changes.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.177-190
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• 2009

Species composition and abundance of marine organism in the Nakdong River estuary were investigated seasonally from November 2007 to November 2008. During the study period, a total of 169 species, 93 families, and 6 taxa were collected in the study area. Species included were 2 species in Bivalvia, 11 in Cephalopoda, 43 in Crustecea, 8 in Echinodermata, 6 in Gastropoda, and 99 in Pisces. The seasonal dominant species in number of individuals were Acropoma japonicum in autumn, Apogon lineatus in winter, Siphonalia spadicea fuscolineata in spring, and Crangon hakodatei in summer. Dominant species in abundance were Chelidonichthys spinosus in autumn, Liphius litulon in winter and spring, and Raja kenojei in summer. The number of species and their abundance, the species composition, and the diversity indices fluctuated with seasons. The organisms were divided into 17 groups by seasonal variation using a self-organizing map.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.180-188
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• 2002

Sand dollar, Astriclypeus manni (Echinodermata: Echinoidea) is widely distributed on subtidal sand flats all along the coast of Cheju Island. Limited information has been reported on their ecology despite their abundance. This study reports gut contents, density and locomotion of the sand dollars distributed on a subtidal sand flat on the north-east coast of Cheju Island. Microscopic examination of the gut contents indicated that A. manni feeds on inorganic and organic detritus as well as live organisms contained in the sediments. Inorganic particles included sand grains, sponge spicules and shells of benthic animals such as foraminifera, crustacean and molluscs. Mean diameter of sediment particles retained in the gut was $77.6\pm{22.2}\mu{m}$. Live organisms retained in the gut included foraminifera, harpacticoid copepods, nematodes, diatoms and unidentified egg. Spatial distribution pattern of the sand dollar was found to be random with a mean density of 0.4 individual $m^{-2}(\chi^2=85.16,\;p>0.05)$. Locomotion speed of the sand dollar measured in situ was 2.0 to 65.0 cm $hr^{-1}$. Locomotion speed and moving distance was somewhat higher in summer when food availability also higher.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.331-337
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• 2017

This study was carried out to analyze the community structure and distribution of macrobenthos at the intertidal zone of Jukbyeon in Uljin-gun during 2015-2016. The number of species were total 41 from 5 phyla. The species composition of Cnidaria 4, Mollusca 19, Annelida 3, Arthropoda 13, Echinodermata 2 and the individuals was $1,642inds./m^2$ and the weight was $1,959.42gWWt./m^2$ in the study area. The dominant species of the upper zones were Chthamalus challengeri and Nodilittorina radiata. Those of the lower zones were Mytilus galloprovincialis, Nipponacmaea schrenckii and Chlorostoma turbinata. The dominant species of the upper zones of winter and spring were C. challengeri, the summer and autumn of the N. radiata. Those of the lower zones were all seasonal of M. galloprovincialis. As a result of cluster analysis, those regions were divided in three groups, which were a group A of December 2015, August 2015 and February to August 2016 of intertidal zone lower, group B of December 2016 and May 2015 of intertidal zone lower, group C of intertidal zone upper.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.843-850
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• 2013

The feeding habits of Lycodes tanakae Eelpout were studied with 722 specimens collected from March 2011 to December 2012 in the coastal waters of the middle East Sea. The main prey of L. tanakae were fish, molluscs and arthropods. Nevertheless annelida, echinodermata and others were found in small amounts in the stomach contents. The L. tanakae stomach was empty of contents in 50.9% of specimens. While smaller size specimens of L. tanakae (less than 40 cm) fed mainly on euphausiids and amphipods, the larger specimens (more than 40 cm) fed on the fish Allolepis hollandi and Icelus cataphractus, and the molluscs Berryteuthis magister and Watasenia scintillans. The main prey items of L. tanakae varied seasonally. The fish Lycodes nakamurai was the dominat prey from November to January during its spawning season. Euphausiids and amphipods of the arthropods were the dominant prey from February to April. The molluscs Berryteuthis magister and Watasenia scintillans were the dominant prey from May to September. The diversity index (H') of diets showed variations by length class and month; the highest values were 2.61 in the length class of 51-55 cm, and the monthly highest were 2.68 in September with 23 species and 2.65 in November with 18 species. The highest dominance index (D') of diets was 0.57 in the length class of 31-35 cm, and the monthly highest was 0.71 in February. Cluster analysis divided prey groups into four groups by length class and three groups by monthly prey items. The gonad index gradually increased during the process of maturation while, contrary, stomach content index decreased during this period.

• 한국해양학회지
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• v.30 no.5
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• pp.442-457
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• 1995

The relationships of environmental factors to the distribution patterns of the three species of ophiuroids, Ophiura kinbergi, O. sarsi and ). sarsi vadicola from Yellow Sea southeast seas and East Sea of Korea were studied to characterize their habitual niches. These three species chosen for study illustrated distinct niche and patterns according to their various preferences mainly for bottom water temperature, bottom water salinity and depth from seven environmental variables which were depth, bottom water temperature and salinity, density, bottom water oxygen content, grain size of the surface sediment, and sediment sorting coefficient. The results of habitat niche study mainly dealing with O. sarsi vadicola suggested that the optimum habitat rages were approximately 6$^{\circ}C$∼10$^{\circ}C$ in bottom temperature and 31%∼33.5% in bottom water salinity which also corresponded with the characteristic ranges of Yellow Sea Bottom Cold Water and higher probabilities of occurrence (more than 70%) were found in depth ranging from 100 to 200 m. In addition, the habitats of O. kinbergi and O. sarsi were compared with that of O. sarsi vadicola. Their ranges of habitat niches were found to have different niches in physical space of bottom water temperature, bottom water salinity and depth. Based on the distribution pattern of O. sarsi vadicola in the Yellow Sea, the ecological barrier which confined the distribution of benthic macro-invertebrates in southern Yellow Sea was determined to be the Yellow Sea Warm Current (approximately 34% < and 18$^{\circ}C$ in December) which occurs between 33$^{\circ}$ and 34$^{\circ}$N of southern Yellow Sea in winter time.

• Development and Reproduction
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• v.13 no.4
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• pp.249-256
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• 2009

The estrogen receptor-related receptors (ERRs) are a group of nuclear receptor superfamily of transcription factors. ERRs and estrogen receptors (ERs) have overlapping affinities for coactivators and DNA binding sites, but differ markedly in ligand binding and activation. The three mammalian ERR genes have been implicated in diverse physiological processes ranging from placental development to maintenance of bone density, whereas the molecular diversity, function, and regulation of ERRs in non-mammalian species are not well understood. In the present study, to investigate the involvement of ERR in transcription and embryogenesis in marine invertebrates, a cDNA encoding ERR (SnERR) was cloned from the gonad in Strongylocentrotus nudus, by polymerase chain reaction (PCR). The amino acid sequence of SnERR showed high homology with that of S. purpuratus (91%). A phylogenetic tree clearly showed that SnERR is a member of the ERR family and clustered in echinodermata group as supported by a high bootstrap value. We examined gene expression of SnERR during embryonic development of S. nudus using real-time PCR. During the embryonic development, the mRNA of ERR was significantly high levels in early development stages (4~64 cell) and larval stages. The SnERR slightly activated transcription through the classical estrogen response elements (EREs) in the presence of genistein. In addition, peroxisome proliferator-activated receptor $\gamma$ coactivator (PGC)-$1\alpha$ knwon as a coactivator of ERR enhanced the snERR-mediated transactivation, suggesting that the PGC-$1\alpha$ is a coactivator of SnERR.