• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.42-47
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• 1998

The chemiluminescent (CL) response of phagocytes from juvenile rockfish, Sebastes schlegeli, which were administered orally with levamisole was investigated. The fish intubated with doses of levamisole either at 0.5mg $kg^-$ or 1 mg $kg^-$body weight showed significant increase in CL responses at two weeks after the administration. The increased extent of CL in the fish exposed to 0.5 mg $kg^-$ body weight was considerably lower than that in the fish exposed to 1 mg $kg^-$. The fish exposed to 5 mg $kg^-$ body weight showed a steady and significant increase of CL response after the intubation. The fish intubated with 10 mg of levamisole $kg^-$ body weight, however, showed no significant differences in CL response after the administration. In the experiment of feeding experimental diet, a lower dose of levamisole induced immunostimulation of phagocytes, but higher doses of levamisole induced immunosuppression of phagocytes. At one week after marking and blood sampling, plasma glucose level was significantly increased in the control group and the group intubated 0.5 mg levamisole/kg body weight. However, the fish in another groups, which were administered higher levels of levamisole, showed no significant difference in glucose level after marking and blood sampling. The result of the present study suggests that levamisole can be used as a potent immunostimulator in rockfish by oral administration, and the immunomodulating activity of levamisole depends on the dosage used.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.200-205
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• 2002

Temperature-dependent pharmacokinetics of ciprofloxacin (CIP) was studied in the cultured olive flounders, Paralichthys olivaceus, and black rockfish, Sebastes schlegeli using high performance liquid chromatography (HPLC) originally developed for quinolone determination from livestock. Pharmacokinetics of CIP was apparently affected by ambient water temperature. In a two-compartment model for flounders after oral dosage of 20 mg/kg, $K_{01},\;at\;13^{\circ}C$ and $23^{\circ}C$ were 4.18 and 1.20/hr, respectively. The $K_{10},\;T_{max}\;and\;C_{max}\;at\;13^{\circ}C$ were 5.574/hr, l4.37${\mu}g/mL\;and\;3.15{\mu}g/mL,$ respectively. The corresponding values at $23^{\circ}C$ were l2.84/hr, 15.39${\mu}g/mL\;and\;6.38{\mu}g/mL$, respectively. The AUC, $T_{1/2} (\alpha)\;and\;T_{1/2}\;(\beta)$ were 278.23 ${\mu}g \cdot hr/mL$, 0.24hr and 47.02hr at $13^{\circ}C$ and 3l7.8l${\mu}g \cdot hr/mL$, 0.30 hrs and 60.78hrs at $23^{\circ}C$ for the flounder, respectively. Similar CIP pharmacokinetics were revealed in the black rockfish after oral dosage of 20 mg/kg under the two water temperature regimes. These pharmacokinetical results have some implication in the optimal usage of recently introduced antibacterials in the farmed fish, which were primarily adapted for poultry and mammalian species.

• 한국수산과학회지
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• 제49권2호
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• pp.224-233
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• 2016

The objective of this study was to develop an artificial neural network (ANN) model for the acoustic identification of commercially important fish species in Korea. A broadband echo acquisition and processing system operating over the frequency range of 85-225 kHz was used to collect and process species-specific, time-frequency feature images from six fish species: black rockfish Sebastes schlegeli, black scraper Thamnaconus modesutus [K], chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, konoshiro gizzard shad Konosirus punctatus and large yellow croaker Larimichthys crocea. An ANN classifier was developed to identify fish species acoustically on the basis of only 100 dimension time-frequency features extracted by the principal components analysis (PCA). The overall mean identification rate for the six fish species was 88.5%, with individual identification rates of 76.6% for black rockfish, 82.8% for black scraper, 93.8% for chub mackerel, 90.6% for goldeye rockfish, 96.9% for konoshiro gizzard shad and 90.6% for large yellow croaker, respectively. These results demonstrate that individual live fish in well-controlled environments can be identified accurately by the proposed ANN model.

• 한국어병학회지
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• 제25권3호
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• pp.231-241
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• 2012

2007년~2011년 하절기에 국내 동 서 남해안과 제주의 육상양식장, 가두리 및 축제식 양식장에서 사육중인 넙치 (Paralichthys olivaceus), 조피볼락 (Sebastes schlegeli), 참돔 (Pagrus major), 흰다리새우 (Litopenaeus vannamei) 의 총 2,413마리에 대하여 세균과 기생충의 감염현황을 조사하였다. 조사기간(2007년~2011년) 사이 어종별 병원체에 대한 감염양상을 종합하면, 기생충과 세균의 단독감염이 혼합 감염에 비하여 비교적 높게 나타났으며, 단독감염 가운데 기생충이 세균보다 감염률이 높은 경향을 나타내었다. 조사기간 동안 넙치, 조피볼락, 새우에서 Vibrio spp. (V. harveyi, V. ichthyoenteri, Vibrio sp.)가 가장 우점종으로 검출된 세균의 위치를 차지하였으며, 참돔에서는 Vibrio sp.와 P. damselae가 우점종 세균으로 검출되었다. 조사기간 동안 가장 우점종으로 검출된 기생충은 넙치에서 스쿠티카충 (M. avidus)과 트리코디나충 (Trichodina sp.), 조피볼락에서 아가미흡충 (M. sebastes), 참돔에서 아가미흡충 (M. tai), 새우에서 섬모충 (Zoothamnium sp.) 으로 나타났다.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.187-193
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• 2003

The performance of a foam fractionator to remove TAN, $NO_2,\;NO_3$, TSS, protein, and $PO_4-P$ at different superficial air velocities and foam overflow heights was evaluated in a lab-scale seawater recirculating system for culture of Korean rockfish (Sebastes schlegeli). The foam overflow rates increased with the increase of superficial air velocities, but decreased with the increase of foam overflow heights. Concentrations of all the water quality variables in the foam condensates increased with the increase of foam overflow height, but decreased with the increase of superficial air velocities. TSS, protein, and phosphate enrichment factors were within the range of 6.4-39.4, 1.6-7.3 and 1.2-3.9, respectively. Low values of TAN, $NO_2,\;and\;NO_3$ enrichment factors were obtained and they indicate that foam fractionation is rot an effective way to remove dissolved inorganic nitrogen. The calculated maximum daily removal values for TSS and protein were 10.9 and 1.4g, respectively.

• 한국수산과학회지
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• 제46권6호
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• pp.761-768
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• 2013

We conducted two feeding trials to investigate the optimal feeding frequency of juvenile Korean rockfish Sebastes schlegeli fed a commercial diet of expanded pellets containing 47.2% crude protein, 9.2% crude lipid, and 14.5% ash at two different water temperatures. In the first experiment, triplicate groups of 20 fish with an average weight of 2 g were fed an equal amount of diet (5.97% based on body weight) at one of six feeding frequencies (2, 3, 4, 5, 7, or 9 meals/day) for four weeks at $17.5^{\circ}C$. After four weeks, we measured weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), and protein efficiency ratio (PER). Fish fed diet five meals/day grew significantly better than those fed nine meals/day. The second experiment used identical experimental conditions and feeding regions, except the food ration was slightly less (5.92% based on body weight) and the water temperature was increased to $20^{\circ}C$. After four weeks, we again measured WG, SGR, FE and PER. Fish fed seven meals/day grew significantly faster than those fed 2, 3, 4, or 9 meals/day. Whole-body protein levels in fish fed three meals/day was higher than those fed four meals/day in $17.5^{\circ}C$ water, but whole-body lipids in the fish fed four meals/day was higher than those fed two meals/day in $20^{\circ}C$ water. A second-order polynomial analysis based on WG suggested the optimal feeding frequency for juvenile Korean rockfish was five meals/day at $17.5^{\circ}C$ and six meals/day at $20^{\circ}C$, indicating that fish reared in higher water temperature require higher feeding frequencies.

• 한국수산과학회지
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• 제46권6호
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• pp.753-760
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• 2013

Two feeding trials were conducted to investigate the effects of feeding rate and frequency on growth performance and body composition of juvenile Korean rockfish Sebastes schlegeli reared at $15.0{\pm}0.3^{\circ}C$. In the first trial, three replicate fish groups averaging $2.07{\pm}0.03g$ were fed a commercial diet with one of seven different daily feeding rates: 1.00%, 2.00%, 2.50%, 2.75%, 3.00%, 3.25%, and satiation (3.34%) based on body weight (BW). After four weeks of feeding, fish fed the 3% diet showed significantly higher weight gain (WG) and feed efficiency (FE) than fish that received the other feeding rates. In the second trial, the optimum feeding frequency was evaluated with three replicate fish groups averaging $2.04{\pm}0.03g$. Fish were fed a commercial diet at 2.87% BW with six different daily feeding frequencies: 2, 3, 4, 5, 7, or 9 meals. After four weeks of feeding, WG, specific growth rate, FE, and protein efficiency rate in fish fed 3 meals $d^{-1}$ were significantly higher than those of fish fed 7 or 9 meals $d^{-1}$. In both feeding trials, proximate composition of the entire body changed depending on the feeding rate or frequency. A broken-line regression analysis based on weight gain suggested that the optimum daily feeding rate and frequency for juvenile Korean rockfish at $15^{\circ}C$ was 2.9% BW $d^{-1}$ and 2-3 meals $d^{-1}$, respectively.

• 한국어류학회지
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• 제25권1호
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• pp.1-8
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• 2013

나프탈렌이 조피볼락의 생존과 아가미의 조직학적 변화에 미치는 영향을 관찰하였다. 실험에 사용된 조피볼락은 전장 $10.36{\pm}0.49cm$, 전중 $16.28{\pm}1.86g$, 270개체이며, 실험기간은 28일이었다. 실험농도는 6개 농도구를 설정하였다(대조구, 에탄올(solvent) 대조구, 0.5, 1.0, 1.5, 2.0 mg Nap $L^{-1}$). 실험기간 동안 사망개체를 매일 파악하여 생존율로 환산하였으며, 실험 종료 후 생존개체의 아가미는 조직표본 제작 후 조직손상의 정도(degree of tissue change (DTC))를 파악하였다. 생존율은 대조구, 에탄올 대조구, 0.5 및 1.0 mg Nap $L^{-1}$에 노출된 개체들은 90% 이상을 나타냈다. 1.5 및 2.0 mg Nap $L^{-1}$에 노출된 개체들은 노출 후 약 20일부터 급격히 감소하여 각각 80%와 62.2%를 나타냈다. 아가미의 조직학적 변화는 새엽 및 새판 상피세포의 증식이 대조구를 포함해 전 노출 농도구에서 관찰되었으며, 농도 증가에 따른 DTC의 증가는 나타나지 않았다. 하지만, 새판 상피층의 탈락 및 융합, 새판 모세혈관 확장, 울혈, 동맥류 및 괴사는 농도의존적 증가를 보였다. 특히 새판의 융합, 모세혈관 확장 및 울혈은 1.0 mg Nap $L^{-1}$ 이상의 농도에서 관찰되었으며, 동맥류와 괴사는 1.5 mg Nap $L^{-1}$ 이상의 농도에서만 관찰되었다. 이와 같은 결과는 생존율의 감소와 아가미의 조직학적 변화가 밀접한 관련이 있으며, 나프탈렌의 독성영향을 결정하는데 있어 DTC의 유용성을 보여준다.

• Fisheries and Aquatic Sciences
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• 제18권2호
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• pp.203-209
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• 2015

Low-value fish is the most commonly used feed in Asian fish farms despite the fact that its application is controversial in regard to the sustainability and biosecurity of aquaculture. In this study, the causal agent of a disease outbreak at a Korean rockfish Sebastes schlegeli farm was investigated to determine whether the low-value fish used at the farm was the source. Infected Korean rockfish and Pacific sand eel used as feed were sampled from the farm, and bacterial cultures recovered from the internal organs of all sampled rockfish were isolated as pure cultures and later identified as Vibrio harveyi. The causal agent of the disease was also isolated from the kidneys of some of the sampled Pacific sand eels. This study provides additional evidence that the low-value fish used as feed at fish farms can be a key source of infectious diseases.

• 한국어병학회지
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• 제17권3호
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• pp.191-198
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• 2004

$estradiol-17\beta$ ${E_2}$에 노출된 미성숙 조피볼락의 혈장 내 vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium (Ca), glutamate pyruvate transaminase (GPT) 및 hepatosomatic index (HSI)의 일시적인 변화가 조사되었다. 70% 에탄올에 녹여진 ${E_2}$ (5 mg/kg B.W.)를 조피볼락 치어의 복강에 주사한 후 0, 1, 3, 6, 9, 12 및 15일에 혈장이 수집되었다. 전기 영동상에서 주사 후, 3일째 약 170 kDa의 위치에 염색성을 나타내는 VTG 밴드가 검출되었다. 밴드의 염색성은 6일째 더욱 강하게 나타났지만, 시간의 경과와 더불어 흐려져 15일째에는 노출 전 처럼 VTG 밴드가 관찰되지 않았다. 혈장 내 ALPP와 Ca는 1일째부터 급격히 증가했으며 VTG 변동과 유사하게 6일째 가장 높은 농도를 나타낸 후, 시간의 경과와 더불어 점점 감소해 15일째는 노출 전과 유사한 값을 나타내었다. GPT는 투여 1일부터 급격히 증가해 3일에 최고치를 나타낸 이후 시간의 경과와 더불어 감소하는 경향을 나타냈으며 HSI의 경우도 1일째부터 증가해 3일째에 가장 높은 수치를 나타낸 후, 점점 감소해 ${E_2}$ 투여전과 유사한 수치를 나타내었다. 이들 결과로 E2에 노출 된 이후 조피볼락의 혈장 내 ALPP, Ca, GPT 및 HSI는 혈장 VTG와 유사한 증․감을 나타내는 것을 알 수 있었다. 따라서, ALPP, Ca, GPT 및 HSI는 VTG와 더불어 연안 생태계 내에서 외인성 ${E_2}$ 노출에 대한 생물학적 지표로서 사용 가능할 것으로 판단되어진다.