• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.136-137
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• 2003

The marine dinoflagellate genus Alexandrium has been recognized as the most representative toxic phytoplankton on account of production of paralytic shellfish poisoning (PSP) throughout the world. PSP producers, generally A, tamarense and A. catenella, within the genus Alexandrium have caused high level intoxicauon of fisheries products and even death of human. In addition, more recent increasing of geographical range of this deleterious species has given rise to alarming tension. The study presented here aimed construction of the molecular phylogenetic relationships through sequences-determination from 16 morphotypic species (containing newly sequenced 3 morphotypic species, A. tamiyavainchii, A. fraterculus and A. pseudogonyaulax) in LSU rDNA D1-D2 and 12 morphotypic species (containing newly sequenced 6 - morphotypic species, A. catenella, A. tamiyavanichii, A. fraterculus, A. affine, A. insuetum and A. pseudogonyaulax) in SSU rDNA region, and the sequences were subjected to comparative-analysis in respect to regional population using functionally expressed rDNA genus and pseudogenes. And we discussed on genetic differentiation between A. tamarense and A. catenella together with putative PSP divegence of the genus Alexandrium. The results of phylogenetic analysis showed the robust monophyletic 14 distinct classes of A. tamarense, A. excavatum, A. catenella, Tasmanian A. tamarense, A. affine (and/or A. concavum), Thai A. tamarense, A. tamiyavanichii, A. fraterculus, A. margalefii, A. andersonii, A. ostenfeldii, A. minutum (and/or A. lusitanicum), A. insuetum, and A, pseudogonyaulx clade. A. fraterculus and A. tamiyavanichii were sister relationship and they were positioned independently between A, affine cluster and those of A. margalefi, A. andersonii, A. ostenfeldii, A. minutum and A. insuetum. A. pseudogonyaulax appeared to be an ancestral taxon among Alexandrium.

• Animal cells and systems
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• v.16 no.5
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• pp.415-424
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• 2012

Four species of ophichthid leptocephali were identified using 12S rDNA sequences, and their morphological descriptions were first provided based on six individuals (S1-S3,M1, and E1-E2) collected from the East Sea and the Korea Strait between September 2008 and October 2010. Mitochondrial 12S rDNA 859-861 base pairs of ophichthid leptocephali were compared with those of 16 ophichthids adult and 2 outgroups (Anguilla japonica and Conger myriaster). Leptocephali of S1 and E1 were very closely clustered with adult of Scolecenchelys borealis (D=0.002) and Echelus uropterus (D=0.000), respectively. However, leptocephali of S2-S3 andM1 were slightly far clustered with leptocephalus of S1 (D=0.006) and adult of Muraenichthys gymnopterus (0.034), respectively. We believe that S1 and E1 are S. borealis and E. uropterus, respectively, in which the former is unrecorded species in Korea. However, S2-S3 and M1 may be undescribed species belonging to genus Scolecenchelys and Muraenichthys, respectively, because total numbers of myomeres for S2-S3 (148-158) and M1 (151) were not consistent with total numbers of vertebrae or distribution for any adult of Scolecenchelys spp. and Muraenichthys spp. in the world. We propose the new Korean name 'Dong-hae-mul-baem' for S. borealis.

• The Journal of Fisheries Business Administration
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• v.44 no.3
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• pp.61-76
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• 2013

This study is aimed to present measures for stable supply of fishmeal and to develop fish farming into a food industry and an export industry. The study analyzed current domestic and international supply and demand for fishmeal and suggested future prospects. The results of the study suggested the basic directions for the stable supply of fishmeal in Korea as follows: first, stable securing of fishmeal importers and establishment of the supply and demand monitoring system; second, policies to boost using of compound feeds and expansion of relevant fishmeal use; third, higher competitiveness of fishmeal and compound feeds through selective and intensive R&D investments. Based on the basic directions, the paper suggested implementation measures such as strengthening of cooperations with fishmeal suppliers abroad, expansion of overseas local market entrance, diversification of fishmeal trading countries, revision of relevant laws and polices on the fishmeal and feeds, organization of domestic fishmeal, promotion of group purchase, improvement of domestic fish meal quality, development of fish meal alternatives, etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.4
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• pp.201-213
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• 1989

This study is just to be carried out to grasp the efficiency of jet stream excavating for the ground. Changing the dynamic pressure, nozzle diameter, distance off the ground, we measured the impulse, the excavated depth, the excavated width. According as each dynamic pressure increases from 100 to $500gf/cm^2$, the impulse of the jet stream increases from 43 to 114gf, from 52 to 227gf, from 114 to 506gf, from 137 to 768gf, in 4, 6, 8, 10mm nozzles respectively, but it makes no difference in the value of distance within 50cm off ground. The excavated depth increases at the invariable rate in accordance with nozzle diameter, dynamic pressure, nozzle distance. We obtain the equations relevant to the ground I, II as follows: $$L_I=[0.01(H/r-100) -0.43\cdot\iota+11.78]{\cdot}D/4$$ $$L_{II}=[0.03(H/r-100) -0.34\cdot\iota+6.39]{\cdot}D/4$$ where, $L_I,\;L_{II}$ are respectively the excavated depths of the ground I, II, cm; H is the dynamic pressure, $gf/cm^2\;:\;\iota$ is the distance off the ground, cm; D is Nozzle diameter, mm; r is the specific weight, $1gf/cm^2$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.543-549
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• 1997

The problems in the existing modeling rules for fishing nets, especially in the Tauti's rule which had been used most commonly, were investigated and it was found that the rules could not give a good similarity between the prototype and model nets because they din neither analyze the flow resistance of nets accurately nor decide the ratio of flow velocity between the two nets properly. Thus, the modeling rule was newly derived by regarding the nets as holey structures sucking water into their mouth and then filtering water through their meshes as in the previous paper. The similarity conditions obtained, between the two nets distinguished by subscript 1 and 2, are as follows; $$\frac{d_2}{d_1}=\sqrt{\frac{l_2}{l_1}},\;\frac{N_2}{N_1}=(\frac{d_1}{d_2})^{1.5}\frac{L_2}{L_1},\;\varphi_1=\varphi_2,\;\frac{d_{r2}}{d_{r1}}=\sqrt{\frac{L_2{(\rho_{r1}-\rho_{w1})}}{{L_1{(\rho_{r2}-\rho_{w2})}}$$ $$\frac{N_{a2}}{N_{a1}}=\frac{W_{a1}}{W_{a2}}(\frac{L_2}{L_1})^2,\;\nu_1=\nu_2\;and\;\frac{R_2}{R_1}=(\frac{L_2}{L_1})^2$$, where L is the length of nettings, d the diameter of netting twines, 2l the mesh size, $2\varphi$ the angle between two adjacent bars, N the number of meshes at the sides of nettings, $d_r$, the diameter of ropes, $\rho_r$, the specific gravity of ropes, $W_a$ the weight in water of one piece of float or sinker, $N_a$ the number of floats or sinkers, $\nu$ the flow velocity, and R the flow resistance of net. In the case where the model experiments aim at investigating the influence of weight in water of nettings on their shapes in nets subjected to the water flow of very low velocity, however, the following condition is added; $$\frac{\rho_2-\rho_{w2}}{\rho_1-\rho_{w1}}=\frac{d_1}{d_2}$$ where $\rho$ is the specific gravity of netting twines.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.85-93
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• 1985

An experimental investigation on condensing heat transfer for the Refrigerant-11 superheated vapor during condensation on the 40 mm O.D by 75 mm long horizontal tube is carried out under the various conditions of air contents as noncondensable gas, condensing pressure, and coolant temperature. The data span a refrigerant flow range from 23 to 63 kg/h and weight fractions of noncondensable gas range from 0 to $15\%$. The comparisons are made using data obtained by the authors and further data obtained from other sources. The characteristics of the condensing heat transfer of refrigerant superheated vapor with and without noncondensable gas flowing horizontally are revealed experimentally, and on the basis of the data obtained, correlations for predicting heat transfer coefficient during condensation on the tube are proposed.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.208-209
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• 2006

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.347-353
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• 1995

[ $F_o-value$ ] of canned smoked-oyster in cottonseed oil (SOCO) were measured using a microcomputer aided $F_o-value$ measuring system, and the microbiological safety of the canned SOCO was evaluated to optimize the energy consumption. Most of the microorganisms in raw oyster were saprophytes. No microorganisms were detected from the canned SOCO which was pretreated by conventional procedure and sterilized at $110^{\circ}C$ with $F_o-value$ of 5.92min and over. The most heat resistant microflora isolated from the raw oyster was Bacillus sp.. D-value at $121.1^{\circ}C$ and z-value of spores of Bacillus sp. in the SOCO homogenate were 4.10min and $10,91^{\circ}C$, respectively. After 120 days storage at $50^{\circ}C$, no growth of microorganisms was recognized from the canned SOCO with $F_o-value$of 5.92min.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.137-144
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• 2001

Sequences of partial 18S rDNA have been analyzed to elucidate genetic diversity of scallops collected around Korean sea, The scallops used in genetic comparison are Argopecten irradians concentricus, Amusium japonicum japonicum, Chlamys farreri farreri, Chlamys (Swiftopecten) swifti and Patinopecten yessoensis. The 18S rDNA sequences were aligned by Clustalx program. Phylogenetic tree was drawn by Treecon program, The scallops were divided into two groups-the Family Pectinidae containing A. japonicum japonicum and the Family Propeamussiidae containing Argopecten, Chlamys and Patinopecten genera. The Family Propeamussiidae was also divided into the Supergenera Aequipecten containing A. irradians concentricus and Supergenera Chlamys containing C. farreri farreri, C. swifti and P. yessoensis. The species of C. swifti was closer to the P. yessoensis rather than C. farreri farreri in respect to nuclear 18S rDNA sequence.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.2
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• pp.125-129
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• 1983

It is customary to assume that the resistance of a jull at uniform speed may be regarded as the sum of viscous and wavemaking component resistance, or C sub(i)=C sub(v)+C sub(w), where C sub(v) is regarded as a function of Reynolds Number R and C sub(w) a function of Froude Number F. Formulae have been obtained for ∂C sub(w)/∂R, ∂C sub(v)/∂F which may be relevant in seeking theoretical grounds for possible interaction between viscous and wavemaking component resistances. The values of ∂C sub(w)/∂R are small. In general they are smaller than corresponding values of ∂C sub(v)/∂R. But although these values are small it does not follow that they are entirely negligible. The Froude assumption that the rate of change of C sub(w) with R is zero must bel regarded as incorrect.