• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.157-164
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• 2009

Due to change of various marine environments according to seawater temperature rising, Japanese common squid(Todarodes pacificus), which was distributed in East Sea, was recently caught in Yellow Sea during a summer season from 2006. The fishery resources density research was carried out in Korea-China Provisional Water Zone using trawl fishing gear and acoustics in National Fisheries Research & Development Institute in Korea. This paper showed the analysis on the acoustical backscattering strength by two frequencies(38kHz, 120kHz) for Japanese common squid by acoustical scattering theoretical model based on size distribution for survey period, and estimate the density distribution for squid s integrated layer which was extracted from any scatterers distributed in water column using two frequency difference method which has been used to distinguish fish shoals or specific target scatterers from sound scattering layer which is composed of various zooplankton. Furthermore, the entire range of their density estimation was suggested using by Monte Carlo simulation under considering each uncertainty such as size distributions or swimming angle and so on in survey area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.385-394
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• 2013

This study has conducted a comparative analysis on the fishing efficiency of LED fishing lamps by squid jigging vessels, the Yeongrak-ho (16 tons) and Somang-ho (9.77 tons), which operated during September and October 2010 and during October 2011, comparing with MH (Metal Halide) fishing lamp-equipped fishing vessels. This study has also examined vessel's fuel consumption level. The light powers of LED fishing lamps of the Yeongrak-ho and Somang-ho were 25.8kW and 32kW, respectively. Those of the MH fishing vessels, that is, the MH fishing lamp-equipped fishing vessels, were 105kW and 81kW, respectively. The average squid catch in number of an LED vessel, Yeongrak-ho, was 39.2% of the MH fishing lamp-equipped fishing vessels; however, that of the Somang-ho improved to 78.7% of the MH fishing lamp-equipped vessels. Average catch in number by Yeongrak-ho crew was 2.6 times more than catch in number by automatic jigging machines. Average catch in number by MH fishing vessel crew was 1.8 times more than that by automatic jigging machines. An LED vessel, Yeongrak-ho's fishing rate was 17.5%~152.2% of the MH fishing vessels, that is, 61.1% on average, in comparison of combined catch in number per automatic jigging machine and per crewmember. Somang-ho's fishing rate was 6.7%~127.6% of the MH fishing vessels, that is, 73.1% on average. The average fuel consumption level of the Somang-ho, throughout its departure from to arrival at the port, was 475.7l, and that during fishing hours was 109.6l, or 23.0% of the total fuel consumption level. Somang-ho's fuel consumption level per fishing hour was 9.7l on average.

• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.19-32
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• 1990

Lipid levels in the tissues of liver and intestines of O.bartrami amounted to 40.0% and 1.5%. The new compounds was found to be ethyl acylates, from a deduction of their detailed $^1H-nuclear$ magnetic resonance(NMR) and $^{13}C-NMR$ as well as infra red spectra (IR). The fatty acid composition of total lipids were mainly composed of C16:0(19.0%), C18:1(16.2%) and $C22:6{\omega}3$(15.7%), followed by C20:1(9.4%), C22:1(6.4%) and C18:0(5.4%). New compound A and B were seemed to derived from the cleavage of glycerol moieties of triglycerides by microbial activities during storage in a frozen state. Compound A contained C16:0(38.2%), C18:1(13:4%), C20:1(13.3%) and C22:1(11.7%) as major components, while compound B predominantly comprised polyunsaturated fatty acid such as $C20:5{\omega}3$ (41.2%) and $C22:6{\omega}3$(36.1%). In both compounds small amounts of odd numbered fatty acids were also detected ($3.8{\sim}2.2%$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.59-61
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• 2014

We conducted eight surveys in the northern East China Sea (ECS) in winter (February - April), summer (July), and autumn (October) 2004-2009, to investigate the seasonal distribution of T. pacificus. A total of 482 paralarvae, ranging in mantle length (ML) from 1.0 - 17.0 mm, were collected at 73 out of 181 stations. There were higher numbers of paralarvae during the winter and summer months than in the autumn. There was significant seasonal variation in the paralarval mantle lengths; mantle lengths were longer in winter (April) than in summer (July). The position of oceanic fronts in the study area played an important role in restricting paralarval distribution along the inshore edge of the Tsushima Warm Current (TWC). When the TWC expanded to western Jeju Island in winter and autumn, the paralarval distribution range extended to include western Jeju Island. However, when the TWC was located southeast of Jeju Island in the summer, paralarvae were distributed along the frontal zone off southeast Jeju Island. Sites at which paralarval mantle length was <2.0 mm ML indicated that the spawning ground were likely to be within the northern ECS in winter and summer, but north of the study area in autumn.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.631-638
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• 2015

This study evaluated the quality characteristics of semi-dried small squid Idiosepius paradoxus treated with grapefruit Citrus paradisi seed extract (GSE) during refrigerated storage for 6 months. The moisture content and water activity decreased significantly in both control and GSE-treated groups with increasing storage time, but there was no significant difference between groups. During storage, the degree of water activity reduction was lower in the GSE-treated group than in the control. The pH change was similar in both groups during storage. The thiobarbituric acid reactive substances (TBARS) value of the GSE-treated group was lower than that of the control until 4 months of storage, and was subsequently higher than in the control group. The Hunter color L value did not differ significantly during storage between groups, whereas the a and b values decreased significantly (P<0.05) in both groups with increasing storage time. The hardness value of the semi-dried small squid increased with storage time, but there was no statistical difference between GSE treatment and control. There were more viable cells in the control group than the GSE-treated group after 5 months of storage. According to the sensory evaluation, neither the taste, color, odor, nor texture differed statistically during storage between groups, while overall acceptability was significantly lower in the GSE-treated group than the control after 6 months of storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.173-179
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• 2012

The common squid $Todarodes$ $pacificus$ is a dominant species in Korean waters, where it is captured preponderantly by the angling fishery. The spawning and nursery grounds of $T.$ $pacificus$ extend from the southern East Sea to the northern East China Sea. Consequently, the environmental conditions in this area during the spawning and nursery seasons might affect the abundance of $T.$ $pacificus$. This study, analyzed the relationship between the distribution of zooplankton and the abundance of $T.$ $pacificus$ and variation in the squid angling fishing grounds in Korean waters. There was a positive relationship between the fluctuations in zooplankton and the catch per unit effort (CPUE; $kg{\cdot}day^{-1}{\cdot}person^{-1}$) of the angling fishery in the East Sea of Korea. The main fishing season is from July to December and the CPUE was closely related to the zooplankton biomass in April in the East Sea. Recently, the center of the squid jigging ground has moved drastically from the area around Ulleung Island to the northern East Sea. We postulate that the fishing grounds of the squid angling fishery will move farther north with climate change.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.132-138
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• 2012

An 8-week feeding experiment was conducted to evaluate three types of squid Sepia esculenta liver powder (SLP) as a dietary protein source replacing fish meal (FM) in juvenile olive flounder Paralichthys olivaceus. To replace FM, six experimental diets were formulated with three types (A, B, C) of SLP at the 5 and 10%: SLP-A5, SLP-A10, SLP-B5, SLP-B10, SLP-C5, and SLP-C10. One control diet contained 100% FM as the main protein source and another was a commercial diet (Com). Fish with an average body weight of $22.8{\pm}0.4$ g ($mean{\pm}SD$) were allocated randomly to aquaria in groups of 20 fish and fed the experimental diets in triplicate to satiation. The weight gain (WG) and specific growth rate (SGR) of fish fed the SLP-C10 diet were lower than those of fish fed the FM and SLP-B5 diets. No significant difference was observed in the WG and SGR among fish fed the diets other than SLP-C10. The feed efficiency (FE) and protein efficiency ratio (PER) of fish fed each SLP diet did not differ from those fed the control diet. However, fish fed SLP-C5 and SLP-C10 had a lower FE and PER than the fish fed commercial, SLP-A5 and SLP-B5 diets. Each SLP diet except for SLP-C10 could replace up to 10% of FM for juvenile olive flounder. The results of this experiment provide information that will assist in formulating an inexpensive practical diet containing SLP for juvenile olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.195-203
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• 2014

We investigated the effect low salt (2 or 4% salt) concentrations jeotgal made from Todarodes pacificus on the learning and memory impairments in scopolamine-induced (2 mg/kg, i.p.) dementia rats. Rats treated with oral BF-7 (200 mg/kg, p.o.) as a positive control and Todarodes pacificus jeotgal had significantly reduced scopolamine-induced memory deficits in the passive avoidance test. The Morris water maze test or treatment with 2% salt jeotgal made from Todarodes pacificus significantly ameliorated the scopolamine-induced memory deficits in the formation of long- and short-term memory. The acetylcholine content and acetylcholinesterase acitivity paralleled the results of the behavior experiment. There were no significant differences in the brain acetylcholine contents of the experimental groups, while the brain acetylcholine content of the group treated with 2% salt Todarodes pacificus jeotgal was higher than that of the control group. The inhibitory effect of 2% salt jeotgal made from Todarodes pacificus on the acetylcholinesterase activity in the brain was lower than that of the control group. These trends were similar to those of the gamma-aminobutyric acid content. We suggest that Todarodes pacificus jeotgal enhances learning memory and cognitive function by regulating cholinergic enzymes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.856-861
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• 2013

The first occurrence of a giant squid, Architeuthis sp. (one specimen), and the oarfish, Regalecus russellii (two specimens) in the East Sea were reported based on specimens collected in January and February 2010. The giant squid (Architeuthis sp.) stranded at Pohang in Jan. 2010 was female, 175 cm in mantle length (ML), 506 cm in tentacle length (TL), and 33.9% FL/ML, it contained common squid beaks. Both stranded oarfish (Regalecus russellii) at Uljin (Jan. 2010) and Yeongdeok (Feb. 2010) were male, with total weigths (TW) of 18,506 and 21,703 g and total lengths (TL) of 3,850 and 3,670 mm, respectively. The stomach of the first was empty, while that of the second was filled with euphausiids. In the East Sea, giant squid have been stranded 14 times in five areas, while 17 oarfish have been stranded in nine areas. Since 1990, the two species have been found most often at Pohang.

• Nuclear Engineering and Technology
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• v.1 no.1
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• pp.23-31
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• 1969

Whole cure shrimp, eviscerated common squid and little squid meats were irradiated with gamma radiation from 60Co using varying dose up to one Mrad. Changes in quality were assessed by organoleptic, chemical (VRS and TMA-N), biochemical (hypoxanthine) and microbiological tests； and the effect of radiation on prolonging of the storage life at 2-4 C was studied. With the cure shrimp, 0.12-0.20 Mrad appears to be optimal with 8 days of storage life, whereas the unirradiated control samples had a storage life of 3 days. With the common squid meat, 0.20-0.30 Mrad appears to be optimal with 14-21 days of storage life, where-as the unirradiated control samples had a storage life of 8 days. And for the little squid meat, 0.12-0.20 Mrad appears to be optimal with 10 days of storage, where-as the unirradiated control samples had a storage life of 5 to 6 days.