• 한국수산과학회지
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• 제51권6호
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• pp.673-681
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• 2018

We isolated and characterized Escherichia coli (E. coli) from oyster Crassostrea gigas and inland pollution sources on Yongnam-Gwangdo island and neighboring areas on the southern coast of Korea in 2014-2015. A total of 222 strains of E. coli were isolated from 132 oysters and 88 samples from inland pollution sources. These 222 isolates were tested for their susceptibility to 24 antimicrobial agents, and 221 isolates were found resistant to the tested antibiotics. Of these 99.5% and 70.7% of the isolates showed very high resistance to rifampin and cephalothin respectively, followed by tobramycin (23.4%), streptomycin (20.2%), tetracycline (19.4%), cefepime (18.9%), ceftazidime (18.9%) and nalidixic acid (16.7%). The resistance rate of E. coli isolated from oysters was higher than that from inland pollution sources. In addition, multiple resistance to at least four antibiotics were present in 73.2% and 26.5% of E. coli isolates from oysters and inland pollution source samples, respectively.

• 한국수산과학회지
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• 제56권3호
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• pp.315-323
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• 2023

The maturity and spawning of the large yellow croaker Larmichthys crocea were investigated using samples randomly collected in the Jeju coastal area, Korea. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), and egg diameter. Additionally, we verified fecundity by size class and total length (TL) at sexual group maturity at 50%, 75%, and 97.5%, as well as by sex ratio (female vs. male). The overall sex ratio of females to males was 1:0.42. The GSI values showed a peak in October, but the spawning season, revealed by the microscopic analysis of gonadal tissue of L. crocea was from October 2021 to March 2022, with the main spawning period from October to November. The fecundity (F) of female L. crocea ranged from 39,232 eggs at 20 to 29.9 cm to 251,003 eggs at 50 to 59.9 cm, with the relationship between TL and F being 80.244TL-1641.6. In females, TL at 50%, 75%, and 97.5% maturity was 22.4, 24.3, and 29.0 cm, respectively.

• 한국수산과학회지
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• 제56권5호
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• pp.691-700
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• 2023

This study examined the seasonal variations of subtidal marine algal community structures along four sites in Jejudo Island, Korea, from February 2016 to November 2018. A total of 147 marine algal species were identified, including 13 green (8.84%), 26 brown (17.69%), and 108 red algae (73.47%). During the study period, the number of species was highest in Sagye (116 species) followed by numbers in Sinheung (98 species), Bukchon (90 species) and Sinchang (73 species). Ecklonia cava, Peyssonnelia caulifera, Synarthrophyton chejuense, Corallina aberrans and Corallina crassisima occurred at all study sites and in all seasons. The average annual biomass of marine algal flora was 746.29±88.85 g wet wt./m² and ranged from 652.25 g/m² at Sinheung to 979.91 g/m² at Sagye. The brown alga E. cava was the most dominant species, occupying 42.85% (319.80 g/m²) of the total seaweed biomass. Subdominant species were C. crassissima and Undaria pinnatifida, comprising 10.22% (76.29 g/m²) and 9.66% (72.13 g/m²), respectively. A similarity analysis showed that there were regional differences in the algal communities, with three distinct groups.

• 환경생물
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• 제36권3호
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• pp.377-384
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• 2018

저염분 순치기간에 먹이를 섭취함으로서 얻을 수 있는 초기 유생의 생리적 변화는 다음과 같이 요약할 수 있다. 하루 동안의 순치기간에 염분농도에 따른 유생의 생존율은 차이를 보였지만 각 염분구간별 먹이섭취 유무에 따른 생존효과는 유사하였다. 그러나 먹이섭취 시 유생이 에너지원으로 활용할 수 있는 cholesterol, triglyceride의 증가가 있었으며 삼투압에 영향을 미칠 수 있는 glucose 농도가 유의적으로 증가하였다. 또한 저염분 순치기간 동안에 스트레스, 조직손상 및 대사작용의 지표가 되는 BUN과 creatine의 감소가 있었다. 먹이섭취로 인한 소화효소의 활성이 먹이를 섭취한 실험구 모두에서 증가하였다. 그러므로 유생발달과 함께 중요한 소화, 순환, 생식기관이 형성되며 탈피 성장을 위한 신진대사가 빠르게 진행되는 유생시기에 저염분 순치가 효율적으로 이루어져 향후 지속적인 성장을 유도하기 위해서는 먹이를 섭취하는 것이 더 효과적인 것으로 판단되었다.

• 한국어류학회지
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• 제31권2호
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• pp.90-100
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• 2019

본 연구는 평창의 남한강 지류 기화천에 출현하는 어류 군집 구조 및 Phoxinus phoxinus와 Rhynchocypris kumgangensis의 분포 특성을 파악하고자 2013년 3월부터 11월까지 조사하였다. 조사기간 동안 총 6과 19종의 어류가 출현하였으며, 개체수 및 생체량 우점종은 R. kumgangensis (Individuals 44.7%, Biomass 30.2%), 아우점종은 P. phoxinus (Individuals 27.7%, Biomass 15.9%)이었다. 고유종은 Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis, Coreoperca herzi 등 10종이었고, 멸종위기종은 P. tenuicorpus, G. brevibarba, P. phoxinus 등 3종이었고, 천연기념물 Hemibarbus mylodon이 출현하였다. 양식용으로 국외에서 도입된 Onchorhynchus mykiss와 국내 이입종인 Oncorhynchus masou masou가 확인되었다. 우점종인 R. kumgangensis는 모든 조사지점에서 출현하였으며, St. 6을 제외하고 b값이 3.0 이상이고 K값의 기울기가 양의 상관성을 보였다. P. phoxinus는 조사지점 St. 3~St. 6에서 출현하였으며, St. 3과 St. 4에서만 안정적인 개체군 상태를 나타내었다.

• 한국수산과학회지
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• 제54권4호
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• pp.404-410
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• 2021

Although, mouse bioassay for the monitoring of azaspiracids (AZAs) toxins in shellfish has been used previously, the reported method has low sensitivity and it is time-consuming. Recently, there is an interest in the quantitative analysis of AZAs using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purpose of this study is to verify the simultaneous analysis of AZAs in shellfish and tunicate in Korea using LC-MS/MS. To validate the method, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and repeatability were determined. All standard compounds were analyzed within 7 min. The correlation coefficients (R²) of the standard solution was higher than 0.9995 (within the range of 0.8-10.0 ㎍/L). The LODs and LOQs of AZAs in shellfish were 0.08-0.16 ㎍/kg and 0.23-0.50 ㎍/kg, respectively. The accuracy and precision of the method for determining AZAs in shellfish were 87.1-93.0% and 1.23-4.91%, respectively. Consequently, the verified LC-MS/MS method is suitable to analyze AZAs in shellfish and tunicates in Korea.

• 한국수산과학회지
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• 제53권6호
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• pp.894-899
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• 2020

This study investigated the effects of inclusion of pollock oil (PO) in the diet of broodstock on the egg and larval quality of Walleye Pollock Gadus chalcogrammus. The experimental diet comprised of semi-moist pellets prepared either with or without PO (control; Con). The fish assigned to each diet were fed to visual satiation (two meals per day) for 12 weeks. Eggs spawned from both groups of fish were sampled during the spawning season (three months) and the egg and larval quality was determined. Total egg volume, fertilization, and hatchability of eggs from the PO group were higher than those of the Con group. Fatty acid composition of fertilized eggs was not affected by the experimental diet. Oleic acid, eicosapentaenoic acid, and docosahexaenoic acid content in larvae of the PO group was higher than that in larvae of the Con group. These results demonstrate the beneficial effects of including PO in the broodstock diet of Walleye Pollock, specifically on the quality of the eggs (total egg volume, fertilization, and hatchability) and larvae (fatty acid composition).

• 생태와환경
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• 제52권1호
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• pp.65-70
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• 2019

본 조사는 월령이 망(보름)인 2016년 4월 22~23일과 5월 25~26일에 낙동강 하굿둑 갑문과 어도 등 총 4개 지점에서 실뱀장어 이동 가능성에 대한 현장 조사를 실시하였다. 실뱀장어는 총 23개체가 채집되었으며, 지점별로 보면 동편 하굿둑에서 22개체, 서편 하굿둑에서 1개체가 채집되었다. 소상지원 시설물 형태 변화, 즉 갑문의 패들 및 어도의 수문 개방 여부, 인조잔디 및 솔의 설치에 따른 실뱀장어의 채집 개체수의 변화를 보면, 동편 하굿둑 갑문의 경우 5개체에서 15개체로 3배 상승하였고, 2번 어도의 경우 0개체에서 2개체로 상승하였다. 본 조사는 2회 조사 결과로 표본수가 작아 모집단에 대한 대표성은 결여되어 있으나, 낙동강 하굿둑 어도와 갑문 모두에서의 실뱀장어를 채집하여 실뱀장어의 하굿둑 어도와 갑문 이용 가능성을 확인하였다. 뿐만 아니라 하굿둑 어도 및 갑문의 소상지원 시설물 형태변화에 따른 실뱀장어 채집 개체수가 현저한 차이를 보여주고 있어, 향후 실뱀장어 회유시기에는 하굿둑 어도 및 갑문을 능동적으로 운영해야 할 것으로 사료된다.

• 한국수산과학회지
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• 제57권1호
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• pp.53-59
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• 2024

The reproductive biology of the Washington clam Saxidomus purpuratus, from Yeosu, Korea was investigated based on 699 individuals collected from January to December 2022. The sex ratio of this species was not significantly different from a 1:1 (male:female) sex ratio (P>0.05). Monthly changes in gonadosomatic index were analyzed to estimate the spawning season. The reproductive cycle of this species can be divided into the following stages: active (Jan.-Mar.), ripe (Mar.-Nov.), spent (Apr.-Dec.), and degenerative (Jun.-Dec.) stages. The spawning period ranged from March to December with the main periods being from April to June and from September to November. The shell length at 50% female group maturity (SL₅₀) was estimated to be 60.2 mm.

• 한국수산과학회지
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• 제54권2호
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• pp.218-223
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• 2021

In this study, the possibility of use as a cartridge for 3D printing was confirmed by adding calcium to the alginic acid-added surimi mixture. The Alaska pollack Gadus chalcogrammus surimi added with alginic acid was immersed in a calcium solution (1 M calcium carbonate, 1 M calcium chloride, 1 M calcium sulfate, and 0.1 M calcium lactate) to evaluate the physical properties, color differences, and sensory properties of Alaska pollack surimi according to calcium types. As the results, in the case of surimi paste to which 1 M calcium carbonate was added, physical properties were weaker than that of 1 M calcium chloride, but gelation was appropriate and sensory properties was excellent. Addition of 1 M calcium chloride has the best physical properties, but it has a problem of bitter taste. With the addition of 1 M calcium sulfate, it has low solubility and poor physical properties as well as poor elasticity and bad taste. Addition of 0.1 M calcium lactate has weak physical properties but good sensory properties. From these results, 1 M calcium chloride has the best physical properties, but there is a decisive problem in sensory properties, so 1 M calcium carbonate is most suitable for commercial use.