• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.739-748
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• 1998

Demersal fishery resources were collected by an otter trawl in May, August and November 1996 at 9 stations off Youngkwang. And they were compared with the data obtained by a stow net, Of 73 species identified, assemblages were consisted of $63.0\%$ in fish, $14\%$ in shrimps, $14\%$ in crabs, $5\%$ in cephalopods and $3\%$ in gastropods. Johnius grypotus, Palaemon gravieri, Crangon hakodatei, Cynoglossus joyneri, Collichthys niveatus predominated in abundance, consisting of $64.4\%$ in the number of individuals. Catch by an otter trawl consisted mainly of demersal fishery resources, while catch by a stow net consisted mainly of pelagic fishery resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.665-672
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• 1998

Feeding habits of Conger myiaster collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. C. myiaster was a carnivore which consumed mainly fishes, shrimps and crabs. Its diets included small quantities of amphipods, gastropods, cephalopods, polychaetes, mysids, cumaceans and isopods. It showed ontogenetic changes in feeding habits. Small indinviduals preyed on shrimps, fishes, crabs, and gammarid amphipods in nearly equal proportions. While the portion of the stomach contents attributable to shrimps and gammarid amphipods decreased with increasing fish size, consumption of fishes increased progressively. C. myiaster showed very constant prey selection regardless of prey availability-Especially fishes were heavily selected by this species throughout the year, although availability of fishes was lower than any other prey organisms in the eelgrass bed.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.349-354
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• 2014

The diet composition of bullet mackerel, Auxis rochei was studied using 200 specimens collected from December 2013 to May 2014 in the coastal waters of Iloilo, Philippines. The size of A. rochei ranged from 11.1 to 31.2 cm in fork length (FL). A. rochei was epipelagic feeder that consumed mainly fishes. In addition, A. rochei consumed shrimps, copepods, crab larvae, amphipods and cephalopods. The diet also included small quantities of stomatopods, bivalves, and ostracods. Also, analysis of the prey-specific abundance against the frequency of occurrence shows that A. rochei have a narrow food niche, and are specialized feeder with fish as their dominant prey. Although fishes were the primary in food consumed by all size class. The fishes gradually increased with body size.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.23-27
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• 2009

The feeding habits of Lateolabrax japonicus were studied based on an examination of the stomach contents of 344 specimens collected monthly from January to December, 2005 in coastal waters off Dolsan-do, Yeosu. The standard length (SL) of specimens ranged in 8.7~52.8 cm. L. japonicus is a piscivore that consumes mainly teleosts such as Engraulis japonicus, Trachurus japonicus, and Acanthogobius flavimanus. Its diet also includes Macrura, Amphipoda, Cephalopoda, Polychaeta, Mysidacea, and Branchyura. Small individuals (<25 cm SL) consume mainly Amphipoda and Macrura. The proportion of these prey items decreases with increasing fish size, and this decrease paralleled the increased fish consumption.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.68-74
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• 2010

Octopus(Octopus minor), benthic cephalopod, were collected from intertidal zone in Seosan, Choongnam and analyzed for polybrominted diphenyl ethers(PBDEs). PBDEs concentrations ranged from 29 to 109 ng/g lipid wt(mean; 54 ng/g) in mantle and from 12 to 89 ng/g lipid wt(mean; 48 ng/g) in internal organ. PBDEs concentrations in octopus internal organ were lower about two times than that in common squid collected in Yellow Sea, indicating Seosan is relatively less contaminated with PBDEs. Major congener was BDE 206, occupying 72% and 49% of total PBDE concentration in mantle and in internal organ, respectively, which is very different from PBDE composition in common squid with major congeners of BDE 47 and 99. From PBDE composition, octopus seemed to concentrate higher brominated BDE rather than lower brominated BDE. This PBDE composition in octopus may be affected by sediment with extremely high contribution of deca-BDE to total PBDE concentration.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.77-82
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• 2019

The feeding habits of pacific cod (Gadus macrocephalus) were studied by analyses of stomach contents. Specimens of G. macrocephalus (n=407) were collected from the western coastal waters of Korea, monthly from July 2017 to June 2018. The size of G. macrocephalus ranged from 30.4 to 86.0 cm in total length (TL). G. macrocephalus was consumed mainly Pisces (71.5%) and Caridea (24.2%) based on % IRI, whereas other prey items including, Paguroidea, Euphausiacea and Cephalopods showed a low contribution to the diet. The feeding ratio of Caridea decreased with increasing fish size. While this decrease paralleled the increased consumption of fish preys. The feeding ratios of Pisces were the highest during spring, autumn and winter, whereas the proportion of Caridea was higher in summer.

• Journal of Marine Life Science
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• v.3 no.1
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• pp.22-30
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• 2018

In this study, pilot study on the introduction of stationary fishery was performed to solve the problem of fisheries resource reduction. The Fyke net, which is a test fishing net was selected considering the environment, operation and management costs of Ulleungdo, conditions that can be operated by small fishing vessels and personnel. As a result of 11 times survey using Fyke net from April to May 2017, 2,735 individuals and 983.4 kg caught and the dominant species were red seabream, yellowtail, olive flounder, mitra squid, horse mackerel, filefish, etc. In conclusion, if the production of squid, which is one of the major fisheries resources of Ulleungdo, is continuously decreased, it is considered that introduction of small-scale stationary fishery such as Fyke net would be useful as a means replace income of fishermen.

• Applied Microscopy
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• v.31 no.4
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• pp.333-345
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• 2001

The mature sperms of three species of cephalopods (Octopus minar, Octopus ocellatus, Todarodes pacificus) were observed by electron microscopy. The results obtained are as follows: The sperm lengths of Octopus minor and Octopus ocellatus of octopods are long and they are about $390{\mu}m$ and $125\sim130{\mu}m$, respectively, but the sperm length of Todarodes pacificus is short and about $35{\mu}m$. The sperm of Octopus minor has a helical acrosome and a head bent a little like a banana while Octopus ocellatus of octopod has a twisted acrosome and a long rod-shaped head. A number of horizontal stripes are observed as a periodic structure in their subacrosome cavities and dense plugs are formed in the cavities of their heads. On the other hand, the acrosome of Todarodes pacificus is circular cap-shaped, and its head is long and oval. It is notable that two small cavities were observed in its basal acrosome. Juxtanuclear acrosomal materials of high electron density filled the subacrosomal cavity. In the middle piece of mature sperms of Octopus minor and Octopus ocellatus, the mitochondria form the mitochondrial sleeve, but the numbers of mitochondria differ between the species so that they are $11\sim12$ and $8\sim9$, respectively. Meanwhile, in the middle piece of mature sperms of Todarodes pacificus, the mitochondria are separated from the axoneme, forming a mitochondrial spur in which $10\sim13$ mitochondria and some electron dense materials concentrate. The axoneme of Octopus minor, Octopus ocellatus and Todarodes pacificus are of 9+2 type in common, surrounded by 9 coarse fibres. A number of glycogen were observed only in the axoneme of Todarodes pacificus. The coarse fibres were found as far as the main piece of sperm tail in Octopks minor and Todarodes pacificus, while to the end piece of sperm tail in Octopus ocellatus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.4
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• pp.213-218
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• 1970

Many investigations have been made on V. parahaemolyticus but to the author's knowledge a report on V. parahaemolyticus found in Korean coastal water has not yet been published. The authors have investigated distribution of V. parahaemolyticus in fish, shellfish, mud, crustacea, sea water and cephalopoda in order to determine the possible origins of food poisoning in Korea. The results are summarized as follows: 1. Fifty six of V. parahaemolyticus were isolated from 517 samples obtained from mud, sea water, fish, crustacea and cephalopoda. 2. The distribution of V. parahaemolyticus isolated from the samples was: 6 strains from mud samples, 7 strains from 44 sea water samples, 28 strains from 241 fish samples, 1 strain from 50 crustacea samples and 2 strains from 34 cephalopoda samples. 3. The strains isolated in the Mokpo area were 7 strains from 48 samples and those isolated in the Pohang area were 2 strains from 46 samples. The number of strains in the Mokpo area was the highest among the strains and the number of strains in the Pohang area was the lowest.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.297-305
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• 2009

The Asian paddle crab, Charybdis japonica (A. Milne-Edwards) is an important fishery resource in Korea. Despite its common occurrence and commercial importance, few studies have been carried out on the life cycle and trophic ecology of these populations inhabiting on the tidal flat. Food habits of C. japonica populations were investigated on the Jangbong tidal flat, Incheon, Korea. Monthly samples were taken using a modified otter trawl from November 1999 to January 2001. Based on the examination of stomach contents from 257 individuals, the frequencies of occurrence and the relative volumes of food items were analysed. As a result, the crustaceans (the brachyura, the cirripedia and the harpacticoid copepoda), the echinoderms (the ophiuroidea) and the molluscs (the cephalopoda Loligo beka, the bivalves Bivalvia unid. and Mytilus galloprovincialis) were important food for this species. To examine ontogenetic shifts in diets, individuals of C. japonica were categorized into 2 different size classes (${\leq}60mm$ and ${\geq}61mm$ in carapace width) representing sexually premature and mature stages. The food items of the small crabs (${\leq}60mm$) were dominated by the crustaceans with the harpacticoid copepods constituting 84.6% of total prey number. The next group was the bivalves and the brachyurans. On the other hand, the large crabs (${\geq}61mm$) mainly feed on the bivalvia (Mytilus galloprovincialis and Bivalvia unid.), the brachyurans (Crab unid.) and occasionally the cephalopods and fishes. The difference in proportions of the main prey items among these two size classes was statistically significant. Therefore, the feeding habits of the portunid crab, C. japonica changed with growth.