• The Korean Journal of Malacology
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• v.32 no.2
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• pp.133-139
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• 2016

The incubation time required for hatching of O. ocellatus were investigated through the processes of egg and embryonic developments by the dissecting microscopic and visual observations. And differences in ecological characteristics of the plankton mode of life or the benthic mode of life according to total numbers of the suckers on each short arm of the hatched juvenile larvae of O. ocellatus were studied by comparisons with other octopodidae species. Compared with the recent a few results reported by other researchers associated with the incubation time required for hatching by female adult mother of O. minor (73-90 days after spawning at $20.9-21.5^{\circ}C$ ranges), in this study, the incubation time required for hatching by female adult mother of O. ocellatus was 56-57 days after spawning at $11.0-20.4^{\circ}C$. Therefore, the incubation time required for hatching by female adult mother varied with Octopodidae species. In this studies, each ovarian egg laid by a female was connected to an egg string attaching to the surface of the wall or bottom of vacunt shell of Rapana venosa. Egg and embryonic developments of this species were studied in the indoor aquaria, in the specific gravity ranging 1.024-1.025. the hatched juvenile of O. ocellatus is 10.3 mm in the mean total length and 4.5 mm in mantle length, and each of its short arms has 18-20 suckers. The just hatched juvenile larvae of O. ocellatus enter the benthic mode of life (benthic larval stage) after hatching. In particular, regarding differences in ecological characteristics of the mode of life according to total numbers of the suckers, O. vulgaris may not need to have many suckers because they enter the planktonic mode of life after hatching, however O. ocellatus may need to have many suckers, because they should adapt to the benthic mode of life. And also the just hatched juvenile larvae of O. minor (bearing many suckers more than O. ocellatus) enter the benthic mode of life (benthic larval stage) after hatching. Therefore, the total number of the suckers on each short arm of the hatched juvenile larvae can be used for determining whether an octopus species has planktonic larval stages or benthic larval stage (benthic mode of life). In particular, The intracohort cannibalism phenomena appeared at the hatched juvenile larval stage because the larval stage of O. ocellatus and O. minor enter into the benthic larval stage in the early stage, unlike entering into the plaktonic larval stage in other Octopus species such as O. vulgaris: at this time, the early hatched larvae fed the late hatched larvae (they are the same species and almost same ages). Therefore, the intracohort cannibalism pheneomena occur in the just hatched juvenile stage of only O. ocellatus and O. minor.

• Food Science of Animal Resources
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• v.20 no.2
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• pp.114-124
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• 2000

In this research the results showed that Evans blue stain causes vascular permeation at antibody injection site by the passive cutaneous anaphylaxis(PCA) screening of octpus minor so we concluded. Octopus minor causes allergy. Psedosciaena Polyactis, Raja Kenojei, Metapenaeus joyneri also showed allergenicity. Microwave and autoclaving appeared to reduced allergenicity(up to 99%) during the technological treatment processing. On the other hand, UV light didn't seem to change the protein structure of allergens affect the allergenicity. Therefore, the technological treatment processing of fish such as canning and microwave would possibly reduce the allergenicity. Among the ultrafiltration fraction of Octopus minor, Pseudosciaena Polyactis, Raja Kenojei and Metapenaeus joyneri, those fraction over 100,000 contained allergen and those under 100,000 and when screening allergenic fish went through 10,000~100,000 ultrafiltration, only the fraction of over 100,000 showed the anaphylactis activity for PCA. However whether screening fish would cause anaphylaxis in human or not is questionable. The future clinical experiment will verify this result with clinical experiment patients.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.55-63
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• 2004

Gonadosomatic index, condition index and reproductive cycle with the gonadal development of the female Octopus ocellatus were investigated by histological observations and morphometric data, from January to December, 2000. And changes in biochemical components of the ovary and the trunk tissues including the digestive organ associated with gonadal development were studied by biochemical analysis from January to October, 2001. The specimens were collected at the coastal waters of Buan, Jeollabuk-do, Korea, from January 2000 to October 2001. O. ocellatus is a dioecious organism. The gonad of O. ocellatus locates medially in posterior region of the body. Morphology of the ovary shows round and oval in shape, the average diameter and external colour of ripe ovary was 32 mm and semitransparent light brown in colour. As the ovary was getting mature, transparent elongated eggs covered with chorion were present in the ovarian cavity. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern with those of the condition index. The GSI and condition index began to increase in March and reached the maximum in April. And then, their values decreased from May and reached the minimum in September. Reproductive cycle of O. ocellatus can be categorized into five successive stages: early developing stage (September to December), late developing stage (November to March), ripe stage (March to May), partially spawned stage (April to June), and degenerative/resting stage (June to October). Follicle cells attached to an oocyte were involved in vitellogenesis in the cytoplasm of the vitellogeneic oocyte and formation of chorion (secondary egg membrane) of the ovarian eggs. Spawning occurred between April and June. The spawning period was once a year and the peak took place between May and June. This species belongs to semelparity. According to changes in biochemical contents of the ovary and the digestive organ, monthly variations of moisture, total protein, total lipid and glycogen contents (%) in the ovary showed a negative correlationship with those of the trunk tissues including the digestive organ. Accordingly, it is assumed that the ovary only may be received nutrient supply (total lipid content) for gonadal development from the trunk tissues including the digestive organ (r = -0.55, p < 0.05).

• Journal of Food Hygiene and Safety
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• v.34 no.5
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• pp.502-507
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• 2019

Cephalopods are one of the most important fishery resources in the world because of their desirable taste and nutritional value. In south Korea, one of the countries in which a large amount of seafood is consumed, cephalopods (e.g., octopus, squid, and cuttlefish) have an annual consumption rate of over 400,000 metric tons. In this study, octopus and squid products (n=28) sold on the market were monitored by analyzing sequences of DNA barcode markers (cytochrome c oxidase subunit I and 16S ribosomal RNA genes). For species identification, the NCBI BLAST database was screened with the sequences and analyzed as a query. In this BLAST search, twelve squid products showed 99-100% sequence identity to Dosidicus gigas (n=3) and Todarodes pacificus (n=9). In the case of the other 16 products that were declared using octopus as raw materials on the labels, six products were identified as Cistopus taiwanicus (n=1), Amphioctopus marginatus (n=1), Scaeurgus unicirrhus (n=1), and Dosidicus gigas (n=3). Monitoring results indicated that a significant percentage (37.5%) of mislabeling was present in octopus products sold on the South Korean market.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2010.05a
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• pp.131-134
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• 2010

• Proceedings of the Malacological Society of Korea Conference
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• 2005.07a
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• pp.9-10
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• 2005

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.3
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• pp.204-213
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• 2010

Test fishing was carried out using six kinds of different mesh sizes (20, 22, 24, 28, 35, 40mm) for springnet-pot to study bycatches according to the mesh size and catches survey was done for another one (mesh size : 22mm, entrance round : 350mm) in Geo-je & Tong-young waters of Korea. On the first sea experiment, it was thought that suitable mesh size of spring-net-pot catching conger-eel over 35cm with decreasing the catches of conger-eel (Conger myriaster) below 35cm was 24mm. On the second sea experiment, commercial catches were crabs (Charybdis bimaculata), octopus minor (Octopus variabilis) and others including conger-eel, and catches proportion was 60% of total catches weights. There was no big difference for the monthly catches. Self-consumption catches were 9 species including conger-eel below 35cm holding 50% of catches in the side of weights. There were 40% of bycatches for the catches weights and 63% for catches numbers in the 22mm mesh size of spring-net-pot having entrance round over 140mm. It showed that 50% of catches weights were discarded.

• Journal of Aquaculture
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• v.10 no.4
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• pp.425-433
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• 1997

The isolated soluble eye proteins from six species (Sepia esculenta, Sepiella japonica, Loligo chinensis, Todarodes pacificus, Loligo beka and Ocotopus minor) of class Cephaloopoda were compared by crossed immunoelectrophoresis methods using antibodies directed against total soluble eye proteins antigens. It showed a distinct antigen-antibody reaction between the species of order Sepioidea and various antiserum of class Cephalopoda. Our results suggested that the common precipitation lines of Sepia and Loligo species which were different from that of Octopus minor. By which obtained from elution of gel filtration chromatography and 12.5% SDS-polyacrylamide gel electrophoresis, the molecular weight of Todarodes pacificus eye protein (crystallin) was determined in abut 20-35 KDa.

• Food Science and Preservation
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• v.15 no.6
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• pp.922-926
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• 2008

The effect of UV-C irradiation on microbial growth and the quality of imported dried filefish and octopus during storage was examined. Samples of imported dried filefish and octopus were irradiated at 0, 5, 10 and $20\;kJ/m^2$ and stored for 3 months at $20^{\circ}C$ or for 6 days at $4^{\circ}C$. Exposure times of 5 min 33 sec, 11 min 6 sec, and 22 min 12 sec were used. UV-C treatment of the imported dried filefish and octopus decreased the populations of aerobic bacteria, yeasts and molds in proportion to radiation dose. Compared to the control, total aerobic bacteria, and yeast and mold populations were significantly lower (1-2 log CFU/g) with UV-C treatment of $20\;kJ/m^2$. UV-C irradiation caused negligible changes in the Hunter color L, a and b values. These results indicate that UV-C irradiation could be useful in inhibiting microbial growth on imported dried fish without impairing quality during storage.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.35-36
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• 2000

낙지, Octopus variabilis, 는 연체동물 중 두족강의 신두족강(Neocephaloda) 팔완목(Octopoda)에 속하고, 주로 우리 나라의 서해안과 남해안을 비롯하여 일본과 중국의 연근해까지 널리 분포하고 있는 연안성ㆍ천해성ㆍ난해성 수족으로서, 연안의 해저 바닥이 뻘로 된 곳에 주로 분포하기 때문에, 낙지어획은 주로 주낙, 기선 저인망, 통발 등에 의해 이루어져 왔는데, 그 중에서 주낙에 의한 어획량이 가장 많다. 그러나 낙지 어업에 대해서는 지금까지 어장학적 연구가 전혀 이루어지지 않았고, 어민들의 경험에만 의존하여 행해지고 있는 실정이다. (중략)