• 한국수산과학회지
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• 제47권4호
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• pp.424-430
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• 2014

Two major temperature fronts, the Subpolar (Gosung, Gang-won-do; $38^{\circ}-41^{\circ}N$) and Thermal (Jukbyun, Gyeong-sang-buk-do; $36^{\circ}-37^{\circ}N$) fronts, are found in the East Sea along the east coast of Korea. These are located roughly where the Tsushima Warm Current and North Korea Cold Current intersect. To clarify the effect of the Thermal Front, we investigated seasonal variation in fish species composition using set nets in two areas located north (Jangho, Gang-won-do) and south (Hupo, Gyeong-sang-buk-do) of Jukbyun, Gyeong-sang-buk-do, and compared the sea water temperature and salinity. We collected a total of 38 fish species in Hupo and 25 in Jangho. Trachurus japonicus was the most common species at both sites, but the subdominant species differed. At Hupo, the subdominant species were Konosirus punctatus and Diodon holocanthus, whereas Clupea pallasii and Scomber japonicus were subdominant at Jangho. Based on Froese and Pauly (2014), subtropical fishes accounted for 55% of fish in Hupo but only for 33% in Jangho. The difference in fish species composition was most obvious in May and August. According to the Korea Hydrographic and Oceanographic Administration, sea surface temperature and salinity were slightly higher at Hupo than at Jangho. Our findings suggest that the oceanographic boundary resulting from the Thermal Front near Jukbyun, Gyeong-sang-bukdo may have a major effect on the distribution of migratory fish species.

• Fisheries and Aquatic Sciences
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• 제3권1호
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• pp.14-22
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• 2000

The relationship between the distribution of demersal fishes and that of the water masses was examined by using the catches data and hydrographic data in the Yellow Sea and the East China Sea on May 13-19, 1996 and May 10-17, 1997. During the study period, the dominant fish species were Cleisthenes pinetorum herzinsteini, Lophiomus setigerus and Pseudosciaena polyactis. These three low temperature water species accounted for $21-24\%$ of the total catches. The percentage of the low temperature water species was high in the Yellow Sea and the coastal area on the continental shelf of the East China Sea but was low in the vincinity of Kyushu during the study period. In the East China Sea, the isotherm of $15^{\circ}C$ at 50m, mid layer depth, was located more southeast in 1996 than in 1997. The bottom water temperature was about it lower in 1996 than in 1997. The direction of the detided current on the continental shelf of the East China Sea was southward in 1996 and northward in 1997. Yellow Sea Bottom Cold Water (YSBCW) strongly expanded to south in 1996 when the northward current was weak. But, Tsushima Warm Current (TSWC) strongly intruded into the continental shelf of the East China Sea in 1997. As YSBCW expanded strongly to south in 1996, the percentage of the low temperature water species relative to the total catches was high. But, TSWC strongly intruded and the percentage of low temperature water fishes was low in 1997.

• 생명과학회지
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• 제20권12호
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• pp.1902-1905
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• 2010

본 연구는 무지개송어 양식 산업의 생산성 향상을 위한 일환으로 염색체공학 기법을 이용하여 전 암컷 무지개 송어의 대량생산을 유도 하였다. 자성발생 2배체를 유도한 후 17 alpha-methyltestosteron으로 성전환을 성공적으로 유도하였다. 성전환된 수컷에서는 일반 암컷 모양을 띤 생식소가 형성 되었으나, 수정관의 발달은 보이지 않는 전형적인 성전환 개체의 특징을 나타내었다. 성전환된 자성발생 2배체 가짜수컷을 이용하여 정상 암컷과 단순교배로 발안율 55.7%, 부화율 52.9%의 전 암컷 집단 97,850 마리를 얻을 수 있었고, 4개월 사육 후 치어기(6~7 cm)때의 생식소 확인 결과 100% 암컷임이 확인되었다.

• 한국물환경학회지
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• 제29권2호
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• pp.232-238
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• 2013

Water temperature is key factor influencing growth and reproduction of fish and its increase give rise to various physiological changes including gene expression. Heat shock protein (Hsp), one of the molecular chaperones, is highly conserved throughout evolution and its expression is induced by various stressors such as temperature, oxidative, physical and chemical stresses. Here, we isolated partial cDNA clones encoding 70-kDa Hsp (Hsp70) and $\beta$-actin using reverse transcriptase-PCR (RT-PCR) from gut of Rhynchocypris kumgangensis, a Korean indigenous species and cold-water fish, and investigated expression profiles of Hsp70 under an increase of water temperature using $\beta$-actin as an internal control for RT-PCR. Cloned Hsp70 cDNA of R. kumgangensis showed homology to Ctenopharyngodon idella (96%), Hypophthalmichthys molitrix (96%), Danio rerio (93%) and Oncorhynchus mykiss (81%) Hsp70. Cloned $\beta$-actin cDNA of R. kumgangensis showed homology to D. rerio (98%), H. molitrix (97%), C. idella (97%) and O. mykiss (90%) $\beta$-actin. Both mRNA of Hsp70 and $\beta$-actin were expressed in gut, brain, and liver in R. kumgangensis. Futhermore, expression of Hsp70, in brain, was highly augmented by an increase of water temperature. These results suggest that Hsp70 mRNA expression level in brain can be used as a biological molecular marker to represent physiological stress against an increase of water temperature.

• Ocean and Polar Research
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• 제41권4호
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• pp.233-250
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• 2019

A re-assessment of the age structure of the population of the Antarctic icefish Pseudochaenichthys georgianus based on body length data covering the years 1976-2009 and including larvae and postlarvae collected in 1989 and 1990 allowed us to define age groups 0, I, and II as containing fish with respective body lengths of 6-9 cm, 15-27 cm and 27-39 cm. Age at maturity (first spawning) was found to occur in age group III at body lengths that have been falling from 50.1 cm in 1979 to 45.4 cm in 1992. Considering postlarvae together with adult fish, the v. Bertalanffy growth curve parameters were determined as L_∞ = 60.62 cm, k = 0.4, t₀ = 0.25. Although the reasons for a maturity at shorter body lengths is not fully understood a host of environmental factors like increasing water temperatures and possibly changes in currents, interspecific competition, food availability, etc. are likely to be involved. Global warming (and not primarily overfishing) is likely to have been responsible for the disappearance of larger fish in the surface waters of South Georgia since 1977, for virtually all commercial fishing stopped in the early 1990s. On the other hand, the appearance of numerous younger spawning individuals suggests that larvae do survive in the colder deeper water below 200 m. The biomass of Ps. georgianus oscillates with a 4-year periodicity in contrast to that of the coexisting icefish Chaenocephalus aceratus: the former with a lower biomass in warm years and a higher one in cold years. The biomass of the third species of icefish in the region, i.e. Champsocephalus gunnari, also oscillates, but with a longer periodicity than that involved in the biology of the other two and its biomass increases in contrast to the other two species. The result is that the biomass all three species considered together is rather stable.

• 한국어병학회지
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• 제17권2호
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• pp.83-90
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• 2004

제주도에서 양식되는 돌돔에서 저수온기에 체표에 출혈성 패혈증 혹은 진무름 및 안구백탁이 수반되며 폐사하는 증상이 지속적으로 발견되었다. 이러한 증상의 원인균으로 추정되는 세균을 병어의 체표 및 장기에서 순수분리하였고 형태학적, 배양적 생화학적 조사 및 16S rDNA sequencing 분석 결과 Pseudomonas anguilliseptica로 동정되었다. 본 균주의 병원성 유무를 확인하기 위하여 인위 감염시험을 실시하였고, 그 결과 시험구에서 21일만에 실험어 20마리 모두가 자연감염된 병어와 유사한 증상으로 폐사하였다. 분리균주의 생육 최적 온도는 $\25^circ{C}$였고 생육 최적 pH는 7-8사이로 좁은 범위를 보였다. 낮은 염분농도에서 생육능이 우수하였으며 3%의 염분이 첨가된 배지에서도 생육능이 양호하였다. 약제내성 검사에서는 doxycycline, chloramphenicol, ciprofloxacin, erythromycin, flumequine, nalidixic acid, norfloxacin, ofloxacin에 감수성이 높게 나타났으나 페니실린계의 항생제에 높은 내성을 나타내었다.

• 한국재난정보학회 논문집
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• 제18권1호
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• pp.194-201
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• 2022

연구목적: 본 연구는 지난 30년(1981~2010년) 동안 우리나라 기후 요인과 근해 어업에서 어획량의 관계를 조사 분석하였다. 연구방법: 본 연구에서 어획량은 한국인 식탁에서 선호되는 7가지 어종을 대상으로 하였다. 본 연구에서는 장기적 추세를 쉽게 파악할 수 있도록 10년 이동평균을 사용하였다. 연구결과: 동 기간 동안 우리나라 연안의 기온과 표층수온(SST)은 모두 상승하였다(p < 0.05). SST의 상승은 기온의 상승과 유의한 상관관계가 있었지만(p < 0.05), 강수량과는 상관관계가 없었다. 2010년에는 1981년에 비해 멸치와 오징어 어획량이 크게 증가한 반면(p < 0.05), 명태는 거의 멸종되어 어획량이 거의 없었다. 이처럼 냉수 어종은 감소하거나 사라지고 어장은 온수 어종으로 대체되었다. 결론: 이러한 결과는 우리나라 근해 어업에서 어획되는 어종이 기후변화, 특히 온난화로 인해 변화했음을 나타낸다. 이는 한반도의 온난화가 가까운 장래에 한국인의 수산물 공급과 식량 안보에 중대한 영향을 미칠 수 있음을 시사한다.

• 수산해양기술연구
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• 제59권4호
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• pp.387-398
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• 2023

Conventional aquaculture faces declining productivity, shifting to recirculating aquaculture system (RAS), known for minimizing water usage and maintaining consistent water temperatures for year-round fish growth. Rainbow trout (Oncorhynchus mykiss), a globally important cold-water species and the third most farmed fish in inland waters of Korea, valued for its fecundity and rapid growth. Dissolved oxygen, an important environmental factor affecting fish production and economics, highlights the need for smart aquaculture practices. Since 2018, the rise of intelligent aquaculture platforms, incorporating information and communications technology (ICT), emphasizes the essential role of RAS implementation. This eight-week study aimed to determine the optimal dissolved oxygen concentration for rainbow trout in RAS, utilizing a device for continuous monitoring, control and record. Dissolved oxygen concentrations were set at 5-6 mg/L, 9-10 mg/L, 14-15 mg/L and 17-18 mg/L. The growth rate significantly decreased at 5-6 mg/L, with no significant differences in other experimental groups. In hematological analysis, growth hormone (GH) was significantly highest at 5-6 mg/L, followed by 9-10 mg/L while Insulin-like growth factor-1 (IGF-1) was significantly lowest at 5-6 mg/L. In conclusion, the optimal dissolved oxygen concentration for rainbow trout in RAS is approximately 9-10 mg/L. Higher concentrations do not contribute to further growth or profitability.

• 한국어병학회지
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• 제26권2호
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• pp.123-128
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• 2013

The outbreak of haemorrhagic speticemia and dermal lesions in cultured Rock sea breem in Jeju Island are frequently associated with keratitis. Prolonged infection leads to the symptoms accompanied by necrosis of fin and skin and the fishes died. Present study aims to study the histopathological changes of diseased fish muscle tissue. The tissue at the initial stage of infection showed normal muscular texture, however in the late stages of infection, muscular lesion had been expanded and hence, necrosis had progressed deeply into muscle tissue. Mild tissue in caudal fin was found with more necrosis, and gill tissues were also collapsed. In Kidney, renal tubules were teared along with tissue destruction (Espada, J et al, 1993). Hence in the present study, we examined the histopathological variation of the infection fishes, and this basic data would be used for future research of in haemorrhagic specticemia and dermal diseases.

• 생명과학회지
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• 제20권11호
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• pp.1634-1639
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• 2010

본 연구는 무지개송어 양식 산업의 생산성 향상을 위해 전 암컷 무지개송어 대량생산을 위한 일환으로 성호르몬에 의한 생리학적 성전환과 자성발생 2배체어를 유도하였다. 생리학적으로 성전환된 수컷을 만들기 위하여 부화 후 첫 먹이를 먹는 시기에 웅성호르몬인 17 alpha-methyltestosterone (MT) 5 mg을 사료에 흡착시켜 사육수온 $13^{\circ}C$에서 적산수온 $800^{\circ}C$까지 처리한 결과 96.7%의 수컷 유도율을 보였다. 또한 정상 수컷 정액을 이용하여 수정 10분 후 $28^{\circ}C$에서 20분간 고온 처리하여 61.7%의 자성발생 2배체가 유도되었다.