• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.740-744
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• 2019

Pacific white-sided dolphins Lagenorhynchus obliquidens inhabit cool temperate waters; in Korean waters, they concentrate near the coast of Gangwon and Gyeongbuk from late autumn to early spring. We collected 15 individuals from Yeongduk, Gyeongju, Ulsan, and Busan between December 2018 and February 2019 and analyzed their stomach contents. Fresh prey items were identified to the species level, and residual stomach contents that were unidentified due to digestion were filtered through a sieve to find fish otoliths and cephalopod beaks. The most important prey items of Pacific white-sided dolphins were cephalopods, composing 68.0% of the diet by occurrence. Fishes were the second largest dietary component, making up 32.0% of the diet by occurrence. Of the cephalopod species consumed, Watasenia scintilans was the principal prey item.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.324-334
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• 2010

This investigation was carried out to research on the actual states for bycatch and discards of catches caught by funnel net from December, 2007 to June, 2010. Fishing grounds were Manheung-dong and Ocheon-dong in the coastal waters of Yeosu. The number of the investigation was 21 in Manheung-dong and 7 in Ocheon-dong fishing ground. In Manheung-dong, the species of catches were 26 of fish, 6 of cephalopod and 5 of crustacean. In Ocheon-dong, the species of catches were 25 of fish, 6 of cephalopod and 4 of crustacean. In the two all fishing grounds, the largest amount of species was revealed as gray mullet. Among these catches, the number of non marketable species that were classified and discarded ones, were 9 in Manheung-dong and 7 in Ocheon-dong. Also, among the marketable species which were small entity or too tiny catches to commercialize and not fresh ones were discarded. The proportion that they dominate in the whole catches was 37.1% in the number of catches and 5.4% in the weight of catches in Manheung-dong, and 6.9% in the number of catches and 0.3% in the weight of catches in Ocheon-dong. In case of Manheung-dong, the monthly discarding proportion was the highest with 59.4% in the number of catches in may and 17.6% in the weight of catches in November, and in case of Ocheon-dong, the both of them were the highest in February, with 28.0% in the number of catches and 5.1% in the weight of catches.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.69-78
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• 2024

We have proposed a method for estimating the size-dependent mortality (M) of short-lived semelparous cephalopod species. To estimate the size-dependent mortality of a winter cohort of the common squid Todarodes pacificus, a commercially important cephalopod species in the North Pacific, we used the data and results of previous studies. On the basis of the bigger-is-better the steady-state hypothesis, we derived a theoretical mortality curve by assuming M as an inverse function of mantle length (ML). The derived constant for size-specific instantaneous mortality (q), assuming an embryonic survival rate of 86.6%, was 0.413 day^-1 mm in ML. Estimates of life-stage-specific M ranged from 0.0280 to 0.435 day^-1 for paralarvae, 0.00278 to 0.0269 day^-1 for juveniles, 0.00197 to 0.00275 day^-1 for pre-spawning adults, and 0.0913 to 0.0920 day^-1 for post-spawning adults. Sensitivity analyses showed that the derived size-dependent M did not significantly change with varying embryonic survival rates, from 48%, the lowest reported value, to 100%. Additionally, comparison of the length frequencies derived from our simulations with those derived from catch data did not show a significant difference, suggesting that our approach and procedures are reliable for stock assessment and management of the common squid.

• CELLMED
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• v.9 no.4
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• pp.7.1-7.4
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• 2019

A cuttlefish bone is not a bone, but the internal shell of the Cuttlefish/ sepia officinalis, a small, squid-like cephalopod of phylum molusca, an animals of the order Sepiida. Cuttlefish bone comprises up to 90 percent of its content of calcium carbonate with the abundance of different bioinorganic elements such as magnesium, strontium, iron, even trace amounts of copper, zinc, aragonite and ${\beta}$-chitin which makes it extremely valuable and worthwhile to be used for biomedical research. Unani system of medicine has been using cuttlefish bone under the name of 'kafe dariya' for the treatment various disorders and ailments since centuries. Unani scholars were well aware of the valuable medical and cosmetologically aspect of cuttlefish bone. However, the drug has been forgotten for its beneficial effect and went deep away from the scientific researches. The purpose of the present review is to highlight and revive the data on cuttlefish and cuttlefish bone for its morphology, composition, types, pharmacological actions, temperament, therapeutic dosage, contraindications, correctives, alternatives and therapeutic uses with special reference of Unani medicine to attain its the beneficial features in biomedical sciences.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.280-288
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• 2018

In this study, an approach for the analysis of the five cephalopod species (octopus, long-arm octopus, squid, wet-foot octopus, beka squid) consumed in the Republic of Korea is developed. The samples were collected from the Southeast Asian countries Thailand, Indonesia, Vietnam, and China. The SYBR-green-based real-time qPCR method, based on the mitochondrial DNA genome of the five cephalopods was developed and validated. The intergroup variations in the mitochondrial DNA are evident in the bioinformatic analysis of the mitochondrial genomic DNA sequences of the five groups. Some of the highly-conserved and slightly-variated regions are identified in the mitochondrial cytochrome-c-oxidase subunit I (COI) gene, 16s ribosomal RNA (16s rRNA) gene, and 12s ribosomal RNA (12s rRNA) gene of these groups. To specify each five cephalopod groups, specific primer sets were designed from the COI, 16s rRNA and 12s rRNA regions. The specific primer sets amplified the DNA using the SYBR-green-based real-time PCR system and 11 commercially secured animal tissues: Octopus vulgaris, Octopus minor, Todarodes pacificus, Dosidicus gigas, Sepia esculenta, Amphioctopus fangsiao, Amphioctopus aegina, Amphioctopus marginatus, Loliolus beka, Loligo edulis, and Loligo chinensis. The results confirmed by a conveient way to calculate relative amplification levels between different samples in that it directly uses the threshold cycles (Ct)-value range generated by the qPCR system from these samples. This genomic DNA-based molecular technique provides a quick, accurate, and reliable method for the taxonomic classification of the animal tissues using the real-time qPCR.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.11-15
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• 2009

The proposal of the $CO_2$ ocean sequestration necessitates a thorough understanding of its consequences to aquatic organisms. This paper describes acute toxic responses to high $CO_2$ environment of a cephalopod, Octopus vulgaris. O. vulgaris was chronically cannulated in the abdominal aorta and recovered in a restrained chamber. Acid base variables as well as ion concentrations were estimated in samples of the blood collected from recovered O. vulgaris. 100% mortality occurred within 72h during exposure to 3%-$CO_2$ environment. Hemolymph pH significantly decreased after 30 min during exposure to 1%-$CO_2$ environment without any compensation thereafter. $[HCO_3^-]$ significantly increased from 2.2 mM at 0h to 7.8 mM at 8h, but gradually decreased thereafter. Hemolymph ions $([Cl^-],\;[Na^+],\;[K^+])$ showed no significant changes. O. vulgaris may be more sensitive than teleost, yellowtail, flounder and dogfish.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.248-262
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• 2005

The purpose of this study was to identify the state of demersal fish resource catch by small trawlers, which live in the southern waters off Goheung. We investigated the results of catch of sample fishing vessels, and performed fishing experiments using the actual fishing operation vessels from early November in 2002 till end of October in 2003. The daily amount of catch per vessel of the 35 small trawlers selected as sample vessels was the highest in summer seasons(June and July) as 70kg and the lowest in winter seasons(January and February) as 45kg and Octopus minor occupied as 17 to 30kg nearly 30% of the total catch. Additionally the catch of Octopus minor per vessel, per dragging hour ranges 3 to 6kg, which is the highest in March and June and the low in January to February, April to May and September. In the fishing experiments using small trawler, during the study period, a total of 75 fish species were collected. The number of individuals by species consisted 58.2% in Shrimps, 17.8% in Fish, 2.3% in Cephalopod. Of these, Parapenaeopsis tenella was the highest in 29.2%, Squilla oratoria and Crangon hakodatel was 14.6% respectively and Octopus minor was 0.2% of the total number of individuals. As far as the appearance number of individuals by month was concerned, February was the highest and then May, April and June followed in order, and October showed the lowest. Additionally the monthly catch per dragging was the lowest in December to January as 20kg and the highest in July as 160kg. Specially, Octopus minor was caught throughout the year regardless of season and the catch was the highest at the period from March to June. When looking into the body mean length of dominant fishes caught, we could observe the followings; Trachurus japonicus 8.9cm, Cynoglossus robustus 10.8cm, Muraenesox cinereus 15.3cm, Setipinna taty 10.3cm, Amblchaeturichfhys hexanema 9.3 cm and Collichthys niveatus 8.9cm, most of which were in their immaturity when they were caught.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.541-546
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• 2017

Feeding habits of dolphinfish Coryphaena hippurus, were analyzed. Fish samples were collected by using a purse seine, fishing and set net in the southern sea of Korea from January to December 2015. The size of C. hippurus ranged from 23.8 to 127.4 cm in fork length. The species with the highest percent index of relative importance (%IRI; the most important prey taxa) in the diets of C. hippurus were teleosts and cephalopod, including Engraulis japonicus, Thamnaconus modestus and Trachurus japonicus, Loligo edulis was the most frequently consumed cephalopods. Coryphaena hippurus also ate small amounts of amphipods and carid shrimp. The dietary compositions of C. hippurus was not significantly different among size classes or seasons (ANOSIM, P>0.05). As body size of C. hippurus increased the mean number of prey per stomach (mN/ST) tended to decrease, but the opposite trend was evident for mean weight of prey per stomach (mW/ST). The mN/ST and mW/ST also significantly varied with season (one-way ANOVA, P<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.709-718
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• 2019

Cephalopods, such as the Japanese flying squid Todarodes pacificus and golden cuttlefish Sepia esculenta, are an important food source for all toothed whales, particularly bottlenose dolphins in costal and offshore waters around the Korean Peninsula. A controlled laboratory experiment was conducted to investigate the broadband acoustic backscattering from live individuals of these two cephalopod species using linear chirp signals (100-200 kHz). The backscattered echo signal was measured at about 1° intervals from -45° (head down) to +45° (head up) in the dorsal plane. The species-specific, frequency-dependent scattering characteristics were investigated by comparing the relationship between the wavelength-normalized backscattering cross-section (σ/λ²) and the wavelength-normalized fish length L/λ for each species. The estimated σ/λ² value for Japanese flying squid was 9.51 at an L/λ range of 12.79-30.27 (mean, 21.26). This was approximately 7% of the σ/λ² value (136.1) for golden cuttlefish at an L/λ range of 9.07-25.49 (mean, 15.77).