• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.284-289
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• 1999

A 15-week feeding trial was conducted to investigate the effect of formulated diet or macroalgae (Undaria pinnatifida) on the survival, growth and body composition of juvenile abalone (Haliotis discus hannai) under the different rearing environmental conditions (four shelter types and two water temperatures). Water temperature was maintained to $16.4^{\circ}C$ by heated and $13.7^{\circ}C$ by not heated natural sea water. The survival rate, weight gain and shell growth of abalone were affected by diet and water temperature (P<0.001). Survival rate of abalone fed the formulated diets was higher than that of abalone fed the Undaria pinnatifida at natural sea water (P<0.05), but this value was not influenced within abalone stocked at heated sea water in each shelter group (P>0.05). Weight and shell growth of abalone fed the formulated diets were significantly higher than those of abalone fed the Undaria pinnatifida at each temperature or shelter (P<0.05). Moisture, lipid and ash contents of the soft body were mainly affected by feeding diet than temperature or shelter (P<0.05). This study indicate that formulated diet used in this experiment could improve the growth of abalone independent of water temperature or shelter. and heated water could show a better growth of abalone in winter season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.242-246
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• 2002

Growth and tetraspore release pattern of lithophyllum yessoense (Rhodophyta, Corallinaceae) were investigated from March 2000 to July 2001. Pinkish tetraspores were 40.2 $\pm$ 0.4 $\mu$m in diameter. After release, tetraspores attached on substrate shortly. Culture conditions were five temperatures (5, 10, 15, 20, 25^{\circ}C), four irradiances (0, 20, 50, 100 $\mu$mol${\cdot}m^{-2}$${\cdot}s^{-1}$) and six salinities (0, 9, 17, 25, 34, 43 ppt). Maximum growth of gametophyte was occurred at $20^{\circ}C$, $20{\mu}mol\;m^{-2}$${\cdot}s^{-1}$, 16: 8h (L:D) and 34 put. Maximum relative growth rate was 0.1232 at $20^{\circ}C$. The amount of tetraspore release showed maximum at September as 266 cells per crust area ($cm^2$), and tetraspores did not release from January to March.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.105-110
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• 2011

This study determined the effects of the dietary moisture level and feeding rate on the growth and gastric evacuation of young olive flounder. Four experimental diets with different moisture levels (9%, 21%, 30%, and 40%) were prepared through the addition of water to the commercial extruded pellet. Three replicate groups of fish (initial weight: $106{\pm}1.4\;g$) were fed diets containing 9%, 21%, 30%, and 40% moisture to satiation or a moisture level of 9% and 30% at a restricted feeding rate (95% of satiation) for 15 weeks. The mean water temperature was $22{\pm}1.6^{\circ}C$ during the feeding trial. Gastric evacuation rates were determined post-feeding. The dietary moisture levels did not significantly affect weight gain, but the weight of the fish receiving 9% and 30% moisture diets to 95% satiation were significantly lower than those of the fish fed 9-40% moisture diets to 100% satiation (P<0.05). The feed efficiency, protein efficiency ratio, viscerosomatic index, and survival were not significantly affected by the dietary moisture levels and feeding rates. The daily feed intake of the fish fed to 100% satiation did not significantly differ among the treatment groups. The stomach contents that peaked within 3 h of feeding gradually decreased, and the stomachs of fish were completely evacuated within 18 h. The contents of the intestine peaked at 3-12 h post-feeding, and then declined with the intestine being mostly evacuated at 30 h. The moisture of the stomach contents reached approximately 70% within 3 h post-feeding and gradually increased to approximately 75% within 12 h. No considerable differences were observed in the gastric evacuation and moisture levels of the stomach contents in the fish fed the different diets. The results of this study suggest that the gastric evacuation of olive flounder was not affected by the dietary moisture level and that the addition of water into the diet displayed no beneficial effects on the growth of young olive flounder.

• Journal of Navigation and Port Research
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• v.41 no.3
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• pp.119-126
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• 2017

As container vessels get larger, container terminals are also likely to grow. The problem that arises is that the growing volume should be handled in the same amount of time as before. Container terminals are introducing an automation system in order to overcome the limitations of existing manual methods and to continuously reduce operating expenses. Because, Manual handling of carrying containers gate in and out of terminals causes inaccurate data, which results in confusion. An alternative is for containers to be labeled with barcodes that can be scanned into a system with a scanner, but this takes quite a long time and is inconvenient. A RFID system, also known as a gate automation system, can solve these problems by reducing the time of gate management with a technology that detects number identification plates, helping operators more efficiently perform gate management work. Having said that, with this system, when container damage is detected, gate operators make and keep documents manually. These documents, which are insufficient evidence in proving container damage, result in customer claims. In addition, it is difficult for gate operators and other workers to manage containers, exposing them to danger and accidents. This study suggests that if an automation system is introduced at gates, containers can be managed by a video storage system in order to better document damage The video system maintains information on container damage, allowing operators the ability to search for videos they need upon customer request, also allowing them to be better prepared for customer claims. In addition, this system reduces necessary personnel and risk of accidents near gates by integrating a wide range of work.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.245-250
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• 2005

The maturity and spawning of Pacific cod, Gadus macrocephalus, was studied using samples caught by gillnets in the East Sea from January to December 2003. Monthly changes of maturity observed with the naked eyes for females showed that maturing Pacific cod appeared from August, and their numbers increased to $83\%\;and\;100\%$ in November and December, respectively. In January, mature and spawning Pacific cod were observed for the first time and composed over $40\%$ of the population. In February, the proportion of spawning individuals increased to over $50\%$, however, the mature individuals decreased to less than $10\%$. In March, mature fish were not found, and all were in an immature (spent) or spawning state. From April to July all fish remained in immature condition. The males maintained this trend with the females, whereas, mature males appeared from November to March. Monthly changes in the gonadosomatic index (GSI) of females and males showed higher values both in January and February and declined sharply in March. The lower value remained until October and then began to increase from November for the female population. For the males, however, this value remained lower until August, and then began to increase from September, and showed higher values in October through December than in January and February. These results indicated that the spawning season of Pacific cod was from December to March, and the main spawning season was from January to February, and the period of the spawning season was longer for males than the females. The diameter of the matured oocytes was 0.80-1.10 mm with a single mode of 0.95 mm. Fecundity was 1,300,000-9,400,000 in total length of 65-95 cm and the relationship between the total length (TL, cm) and fecundity (Fc) was Fc= $180,248\timesTL-10,883,638$. The total length at first maturity was observed at 57 cm for females and 47 cm for males. The size at $50\%$ group maturity was estimated to be 63.9 cm for females and 56.0 cm for males.

• Korean Journal of Ichthyology
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• v.12 no.1
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• pp.38-45
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• 2000

Depending on the fish species the vascular tone is distinctively regulated by numerous vasoactive substances. In most fish species the regulatory role of autonomic neurotransmitters and other vasoactive substances are not well defined. This research was designed to delineate the regulatory role of various endogenous autonomic neurotransmitters known to be important in mammalian vascular systems on isolated Israeli carp ventral aorta. Acetylcholine(ACh) contracted the aorta regardless of the pre-existing level of vascular tone, and the contraction was almost completely abolished by a cholinergic-muscarinic antagonist atropine. Endogenous, multiple receptor ($\alpha$ and $\beta$)-acting adrenergic agonist epinephrine (Epi) relaxed the vessel in the presence and absence of the pre-existing tones. Another endogenous multiple receptoracting agonist norepinephrine (NE) weakly contracted the aorta in non-preconstrcted state, but the response was reversed to relaxation when preconstricted. Isoproterenol, ${\alpha}\;{\beta}$ adrenergic receptor agonist, was a potent vasodilator whereas an ${\alpha}_1$ agonist phenyephrine was a contractor. The ${\alpha}_2$ adrenergic receptor agonist clonidine has not any significant effect in altering the vascular tone. The vasorelaxing action of Epi, NE and isoproterenol was significantly attenuated by $\beta$ receptor antagonist propranolol. These results imply that ACh may primarily play a contractor role via muscarinic receptor activation while adrenergic agonists, Epi and NE, are relaxants through activation of $\beta$ adrenergic receptors in vivo.

• Journal of Aquaculture
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• v.21 no.2
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• pp.102-106
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• 2008

This study was conducted to evaluate extruded pellets(EP) for the growth of sub-adult flounder Paralichthys olivaceus by comparing with raw fish-based moist pellet(MP). Two replicate groups of 150 fish per each tank(initial mean weight $594{\pm}6.5g$) were fed one of two EPs(EP1 and EP2) and a MP for 32 weeks. Survival was not significantly affected by experimental diets. Final mean weight of fish fed the EP1 was not significantly different from that of fish fed the MP, but that of fish fed EP2 was significantly lower than that of fish fed EP1 and MP (P<0.05). Feed efficiency and protein efficiency ratio of fish fed the EP1 and EP2 were significantly higher than those of fish fed MP(P<0.05). Daily feed intake of fish fed the EPs was significantly lower than that of fish fed MP(P<0.05). Condition factor was not significantly different among all groups. The contents of moisture, crude protein and lipid in dorsal muscle were significantly affected by experimental diets(P<0.05). Based on the results of this study, the dietary formulations used in EP1 and EP2 could be applied in the practical extruded pellet feeds for sub-adult flounder(594-1,126 g).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.4
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• pp.199-205
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• 2015

Nitrogen and phosphorus are the limiting elements for growth of phytoplankton, which is a major primary producer of marine ecosystem. Incidentally the stoichiometry of N/P of ocean waters, measured by the (nitrate + nitrite)/phosphate ratio converges to a constant of 16. This characteristic ratio has been used widely for the understanding the ecosystem dynamics and biogeochemical cycles in the ocean. In the East Sea, several key papers were issued in recent years regarding the climate change and its impact on ecosystem dynamic and biogeochemical cycles using N/P ratio because the East Sea is a "miniature ocean" having her own meridional overturning circulation with the appropriate responding time and excellent accessibility. However, cited N/P values are different by authors that we tried to propose a single representative value by reanalyzing the historical nutrient data. We present N/P of the East Sea as $12.7{\pm}0.1$ for the year 2000. The ratio reveals a remarkable consistency for waters exceeding 300m depth (below the seasonal thermocline). We recommend to use this value in the future studies and hope to minimize confusion for understanding ecosystem response and biogeochemical cycles in relation to future climate change until new N/P value is established from future studies.

• Korean Journal of Ichthyology
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• v.29 no.1
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• pp.32-40
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• 2017

Samples were obtained from broodstok in May, 2010, while naturally fertilized embryos were maintained, and the process of skeletal development was observed from larvae and juvenile. Prelarvae immediately after hatching showed an average total length of $6.85{\pm}0.63mm$ (n =5), Premaxillary and dentary were ossified, parasphenoid was ossified in the cranium, and centrum and caudal bone did not ossify. Prelarvae showed ossification with maxillary, articular, and epihyal, and branchiostegal rays of hyoid arch were ossified at 2 to 3 days after hatching with an average total length of $7.25{\pm}0.28mm$ (n=5). The vertebrae began to ossify in the direction of the tail, and neural spine began to ossify above the ossified vertebra. Postlarvae showed ossification of lateral ethmoid, alisphenoid, parietal, and caudal skeleton in the cranium when the average total length was $9.00{\pm}1.53mm$ (n=5) in 6 days after hatching. At 40 days after hatching, postlarvae ossified maxillary in the cranium, and ossified endopterygoid and ectopterygoid, etc. in the palate, when the average length of $23.3{\pm}0.28mm$ (n=5). At 120 days after hatching, with the average length was $37.5{\pm}2.83mm$ (n=5), caudal skeleton had one additional epural bone ossification, resulting in ossification of a total of 3 epural bone to complete ossification of all spicules.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.419-424
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• 2018

In this work, effect of the culture medium composition on the fermentation process of Clostridium ljungdahlii, which is acetogenic bacteria to product ethanol from synthesis gas, was examined to improve the microbial growth and ethanol production. Components of the culture medium such as yeast extract, fructose, $NH_4Cl$, and $K_2HPO_4$ were selected as influence factors for the cell growth and ethanol production. As the concentration of yeast extract increased, both of the cell growth and ethanol production increased. And the ethanol productivity was the highest at an yeast extract of 0.05 g/L, which is lower than that of base medium. As the concentration of fructose increased, the cell growth increased, but the ethanol production decreased when the concentration of fructose was higher than that of base medium (5 g/L). In an experiment with the yeast extract of 5 g/L, produced ethanol concentration was the highest (0.297 g/L) when fructose concentration was 5 g/L, however, the specific ethanol productivity was higher (0.281 g/g DCW) when the fructose was not added due to very low cell mass. The cell growth and ethanol production were not significantly influenced by $NH_4Cl$ concentration, however the growth inhibition was observed at a 30 g/L of $NH_4Cl$. When the concentration of $K_2HPO_4$ increased, both of the cell growth and ethanol production increased. In experiments with $NH_4Cl$ and $K_2HPO_4$, specific ethanol productivities were higher when the low concentration of yeast extract was used.