• 한국수산과학회지
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• 제37권1호
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• pp.7-12
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• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• 한국양식학회지
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• 제7권3호
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• pp.135-150
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• 1994

은어의 효과적인 인공 종묘 생산을 위하여 자어의 성장과 생존율에 대한 먹이생물의 영양 가치에 대해 실험하여 다음과 같은 결과를 얻었다. 자어의 rotifer type에 따른 먹이효율을 조사하기 위해 3개 rotifer type (L-type, S-type, Us-type rotifer)을 각각 단독 또는 혼합하여 공급하였을 때 자어의 생존율은 모든 실험구에서 차이가 없었으나, 성장은 3 개 type rotifer를 모두 혼합하여 공급한 실험구에서 가장 높았다. Rotifer와 Artemia nauplius를 Chiorefla effipsoidea, 유지효모, 건조분말 Spimlina Platenis, Super Selco로 영양 강화시켜 자어에 공급한 영양 강화 실험에서 건조분말 S. platenis와 Super Selco를 혼합하여 영양 강화시킨 실험구에서 가장 높은 성장과 생존율을 보였다. Rotifer와 Arremia nauplius 공급시 자어의 사육 수조에 green water의 효과를 조사하기 위해 Chforefia ellipsoidea, 건조분말 Spimfina platensis, 광합성 세균(Rhodopseudomonas capsulatus)을 green water 원으로 사용하였을 때 건조분말 Sprinlina platenis와 광합성 세균을 혼합하여 공급한 실험구에서 가장 높은 성장과 생존율을 나타냈다.

• 한국수산과학회지
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• 제40권4호
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• pp.183-186
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• 2007

The effect of live food and commercial diet on sweetfish Plecoglossus altivelis culture was assessed by determining the daily growth rate and feed conversion ratio. After feeding for 8 weeks, the Moina macrocopa diet resulted in a higher growth rate of 5.101 compared to commercial (3.441) and Artemia (2.729) diets. In addition fish fed the M. macrocopa diet had the weight gain, averaging 41.29 g at the end of the experiment. The content of n-3 highly unsaturated fatty acids (HUFA) was highest in the commercial diet, while free fatty acids were not detected in the M. macrocopa diet. Triglycerides, the energy source in fishes, constituted 40.0% of the M. macrocopa diet, which was significantly higher than in the commercial and Artemia diets at 20.0 and 12.0%, respectively These results indicate that freshwater M. macrocopa can be used as feed for sweetfish larvae, even without docosahexaenoic acid (DHA) enrichment from Artemia.

• 한국수산과학회지
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• 제52권5호
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• pp.496-510
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• 2019

We investigated the reproductive characteristics of the sweetfish Plecoglossus altivelis, including changes in the gonadosomatic index (GSI), frequency of gonad developmental stages, and abundance of drifting larvae, in three streams (Gangjeong, Yeonoi, and Ongpo) on Jeju Island from May 2004 to December 2005. The GSI values of female P. altivelis in all Jeju streams began to increase in September and reached a maximum in October and November. Peak GSI values in males occurred in Gangjeong from October to November, in Yeonoi from November to January, and in Ongpo from September to October. The gonadal development of P. altivelis was classified into four stages: growth (March to October), maturity (September to December in females; July to December in males), spawning (September to January), and degeneration (October to March in females; after November in males). Drifting larvae were collected from October to January. These results suggest that the main spawning activity of P. altivelis in Jeju streams occurs from October to November. The information about the reproductive characteristics of P. altivelis obtained in this study is critical to fishery management for this species.

• Parasites, Hosts and Diseases
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• 제28권4호
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• pp.253-256
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• 1990

1989년 8월 강원도 양양군 현북면 광정천과 양양읍 남대천에서 잡은 은어에서 요꼬가와 흡충 피낭유충 감염상을 조사하였다. 광정천산 은어는 조사한 28마리 모두(100%)가 피낭유충 양성이었고 어체 마리당 89∼521개 (평균 224개), 어육 g당 12∼55개 (평균 22개)의 감염량을 나타내었으나, 남대천산 은어(6마리)에서는 피낭유충이 검출되지 않았다. 이상의 결과로 강원도 양양군 현북면 지역이 요꼬가와흡충 유행지의 하나임을 확인하였다. Key words: Metagonimus yokogawai, metacercarial prevalence, sweetish, Kwangjung·stream, Namdae-stream, Yangyang·gun(Kangwon-do)

• 생태와환경
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• 제40권2호
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• pp.337-345
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• 2007

2004년부터 2005년에 걸쳐 옥정호 육봉형 은어(Plecoglossus altivelis)의 성장에 따른 식성 및 섭식기관의 변화를 조사하였다. 호소에 서식하는 체장 $25{\sim}40$ mm의 후기자어는 요각류, 물벼룩류 및 윤충류를 주로 섭식하였고, 체장 $50{\sim}60$ mm의 치어는 파리목의 깔다구류, 요각류 및 물벼룩류를 주로 섭식하였다. 반면에 추령천에 소상한 $60{\sim}70$ mm의 치어는 동물성 먹이와 조류를 같이 섭식하였으며, 70mm 이상의 미성어는 Synedra, Cymbella, Navicula 및 Pinnularia와 같은 부착 조류를 주로 섭식하였다. 또한 성장 및 먹이생물과 관련하여 이(teeth)와 위 (stomach)의 형태도 바뀌었다.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.78-84
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• 1984

경북 월성군 치슬령 북측 능선에서 기원하여 포항시 송정동에 하구를 형성하고 있는 외출람에 호식하는 담수어와 반철수어에서의 흡충류 피낭유충 기생상을 알아보기 위해 1983연 3월부터 동년 10f3까지 형산강 유역에서 투망, 낚시, 사발모지 등으로 담수어와 반섬수어를 채집하였다. 채집된 어류는 어종별로 분류한 다음 어체 부위별로 흡충류 피낭유충의 기생상을 조사함과 동시에 신선한 어육 1gram당 피복유충수를 계산하여 감염정도를 추정하였다. 채집된 11종의 어류에서 7종의 흡충류 피습유충과 소속미정 유충을 검출할 수 있었으며, 이 가운데 Exochits oviformis유충은 전 피검어에서 검출할 수 있었고, Metagonimus yokognwai유충은 9종의 어류에서, Cyathocotyle orientalis 유충과 Metacercaria hasegawai 유충, Metorchis orientalis 유충은 6종의 어류에서, 간흡충 피낭유충은 4종의 어류에서 검출할 수 있었으며, 그 기생률은 어종별로 큰 차리를 보였다. 어육 Igram당 간흡충 피낭유충 평균수는 몰개에서는 45.5개로 가장 많았고 납지리에서는 0.05개로 가장 적었으며 참붕어와 돌고기에서는 각각 9.7개, 11.6개로 중간치를 나타내었다. 횡천흡충의 피낭유충수는 붕어, 몰개, 버들치, 납지리, 참붕어, 퍼래미, 같겨니에서 모두 10개 이하 이었는데 비하여 은어에서는 32.9개로서 담수어보다 반철수어에서 그 수가 많았다. 이상의 성적으로 미루어 보아 경북 형산강에 서식하고 있는 담수어와 반철수어의 회를 생식하면 간흡충증과 횡천흡충증에 감염될 것으로 추정된다.

• Parasites, Hosts and Diseases
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• 제25권1호
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• pp.59-68
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• 1987

An epidemiological survey on Metagonimus yokogawai infection was performed in the eastern coast area of Kangwon province. Formalin-ether concentration technique and Stoll's dilution egg counting method were employed to figure out the prevalence and intensity of M. yokogawai infection and eating habits of inhabitants with raw freshwater fish. The results are summarized as follows: 1. The prevalence rate of M. yokogawai infection was 6.6% among a total of 2, 357 examinees; 8.6% (115 out of 1, 345) in male and 4.0% (40 out of 1, 012) in female. 2. The prevalence rates were different by the streams where the examinees were residing: 17.8% along the area of Ohsip-cheon (stream), 11.8% along Maeup-cheon, 1.7% along Hwasang-cheon, 1.3% along Yeongok-cheon, 0.9% along Namdae-cheon, 0.9% along Sa-cheon and 0% in the other streams (Yongchon-cheon, Kangnung Namdae-cheon and Jusoo.cheon) in decreasing order. 3. By social strata, the positive rate was 8.0% (122 out of 1, 521) in general inhabitants and 3.9% (33 out of 836) in school children. 4. By the intensity of infection by means of EPG counts in feces; the light infection (less than 400/EPG) was 74.1%, moderate infection (401-1, 000/EPG) 17.3% and heavy infection (more than 1, 001/EPG) 8.6%. 5. Twelves out of 50 sweetfish (Plecoglossus altivelis) (24%) caught from the streams in eastern coast of Kangwon-Do were infected with metacercariae of M. yokogawai, and the number of larvae detected were 70.7 per 6sh in average. The metacercarial infection rates in fish were also different by the streams; 100% in Ohsip-cheon of Samcheok-Gun, 14.3% in Sa-cheon, 16.7% in Yeongokcheon of Myeongju-Gun and 0% in Namdae-cheon of Yangyang-Gun, respectively. 6. Six hundred ninety live (695) out of 1, 396 inhabitants and school children (49.8%) were experienced in eating raw freshwater fishes (Plecoglossus altivezis, Triboledon hakonensis, Coreoperca sp., Morose sp., Carassius sp. & Cyprinus sp. and Zacco platypus). The data were assayed with the questionnaire collected from the examinees. In summarizing the above results, it is known that the Ohsip-cheon area of Samcheok-Gun is highly infected region, and the other areas of Kangnung Namdae-cheon, Yeongok-cheon and Yangyang Namdae-cheon are very lowly infected or non-infected regions for M yokogawai infection.