• 한국수산과학회지
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• 제52권6호
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• pp.740-744
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• 2019

Pacific white-sided dolphins Lagenorhynchus obliquidens inhabit cool temperate waters; in Korean waters, they concentrate near the coast of Gangwon and Gyeongbuk from late autumn to early spring. We collected 15 individuals from Yeongduk, Gyeongju, Ulsan, and Busan between December 2018 and February 2019 and analyzed their stomach contents. Fresh prey items were identified to the species level, and residual stomach contents that were unidentified due to digestion were filtered through a sieve to find fish otoliths and cephalopod beaks. The most important prey items of Pacific white-sided dolphins were cephalopods, composing 68.0% of the diet by occurrence. Fishes were the second largest dietary component, making up 32.0% of the diet by occurrence. Of the cephalopod species consumed, Watasenia scintilans was the principal prey item.

• Applied Microscopy
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• 제27권2호
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• pp.189-196
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• 1997

The ultrastrucures of Xenopus otic vesicle from normal embryo (st. 43) and induced otic vesicle from animal cap assay with Activin A were compared. Activin A was applied to the presumptive ectoderm at various concentrations for three days at $20^{\circ}C$. The results were almost identical to the reference studies, but it was found that the otic vesicle was induced at the concentration of 10 ng/ml in to)v rate. This otic vesicle may be secondarily induced by the neural tissue showed commonly at the concentration of 10 ng/ml. Otoliths were observed as three or four-axis crystaline bodies in the lumen of otic vesicle. In electron micrograph of the normal embryo, two kinds of microvilli were observed on the apical position of hair cells. One was small and common, the other was large-sized and sparsely distributed. In both cell of otic vesicle, mitochondria, golgi apparatus and multivesicular body were rich, so, they showed a lot of similarities in ultrastructure. However, the otolith was not found and microvilli were overexpressed in the otic vesicle induced by Activin A.

• 한국수산과학회지
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• 제22권1호
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• pp.36-40
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• 1989

The eels, Anguilla japonica, were reared in a tank with daily feeding for up to 97 days, and otoliths were regularly collected for the observation of their microstructures. Microscopic observation of the thin-sectioned otolith under dark field provided significant information on daily growth increments as well as the difference in visual contrast shown by the increments. Clearly defined elver mark formed during the metamorphosis from leptocephalus to the elver can be considered as the origin of the age for the sedentary yellow eel in continental water. The close correspondence between the number of increments outside elver mark and chronological age in days from the beginning of feeding indicates that increment deposition on a daily basis was initiated with the start of feeding for the sedentary yellow eel. Either 7 or 14 daily growth increments were grouped together into 2 alternative units, each distinguished by prominent checks or by visual contrast. The absence of any apparent environmental variations with 7 or 14 day period in the reared tank implies that the phase of the moon could be a zeitgeber for the endogenous rhythm.

• 한국수산과학회지
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• 제37권4호
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• pp.307-311
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• 2004

Age and growth of red tongue sole (Cynoglossus joyneri), were studied using samples from the coastal waters off Yeosu, Korea, from January to December, 2001. Sagittal otoliths had relatively clear annuli. Marginal index of otolith dropped sharhly in August suggesting that each annulus was formed once a year In August. Monthly changes in the gonadosomatic index indicated that spawning peaked between July and September. The oldest fish observed in this study was 4 years old for both of females and males. Relationships between the otolith radius (R) and total length (L) were: L=14.1R-0.098 for females, and L=11.9R+1.83 for males. Relationships between total length and body weight $(W)\;were:\;W=0.0021L^{3.24}\;for\;females,\;and\;W=0.0014L^{3.39}$ for males. Growth in length of the fish was expressed by the von Bertalanffy's growth equation as:$L_{t}=29.06\;(1-e^{-0.19(t+2.40)})\;for\;females\;and\;L_{t}=27.44 (1-e^{-0.17(t+2.84)})$ for males.

• 한국해양학회지:바다
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• 제13권1호
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• pp.83-88
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• 2008

미세채취기를 이용하여 보구치(Argyrosomus argentatus)의 이석으로부터 탄산염 시료를 매우 조밀하게 채취하여 성장에 따른 고해상의 안정동위원소비의 변화를 조사하였다. 이석의 ${\delta}^{18}O$값과 ${\delta}^{13}C$값은 성장에 따라 점진적으로 증가하는 경향을 보였다. 그러나, 이러한 증가는 서식환경의 변화에 의한 것이 아니라, 초기성장동안 어류의 생리적인 작용에 의한 영향을 많이 받다가 점차적으로 줄어들면서 해양환경에 평형을 이루는 것으로 해석된다. 이 연구 방법과 결과는 앞으로 다른 어류의 이석으로부터 고해상의 안정동위원소 변화를 획득하여 어류의 성장과 서식환경의 변화를 연구하는데 적용할 수 있는 가능성을 제시한다.

• 한국어류학회지
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• 제26권3호
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• pp.194-201
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• 2014

태안 연안에서 이각망에 어획된 숭어 이석을 관찰하여 연령을 사정하고, 이석 윤문의 폭으로부터 체장을 역추정하여 성장을 추정하였다. 태안 연안 숭어는 외해에서 산란하여 유어기를 보낸 후 성어가 연안으로 들어온 것으로 보이며, 관찰한 숭어의 전장은 239~605 mm 범위였으며, 400~550 mm 크기의 개체가 주를 이루었다. 나이는 1~7세 범위였고 3~5세어가 가장 많았다. 전장(L, mm)은 이석의 장반경(R, ${\mu}m$)에 유의하게 일차 비례하였다(L=15.3+87.9 R). Frazer-Lee의 방법으로 추정한 각 연륜이 형성되었을 때의 전장은 1세어의 평균(${\pm}SD$)은 $316{\pm}40.6mm$로 초기 성장이 빨랐으며, 각 나이에서 그 범위가 넓어 개체에 따른 성장률 차이가 큰 것으로 보인다. 역추산한 전장은 Von Bertalanffy의 성장식 $L_t=542[1-{\exp}\{-0.493(t+0.769)\}]$로 유의하게 회귀되었다.

• 한국어류학회지
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• 제27권2호
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• pp.133-141
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• 2015

본 연구는 한강 하구역 가숭어 자원생태의 기초정보를 제공하기 위해 2013년 6월부터 2014년 5월까지 총 12개월 동안 한강 하구역에서 어획된 가숭어를 구입하여 연령사정을 실시하였다. 분석 결과, 가숭어의 주 산란시기는 5월로 추정하였고, 윤문은 1월 (연 1회)에 형성하였다. 체장과 체중의 관계식은 $TW=0.0124SL^{3.0133}$($r^2=0.9931$)였다. 가숭어의 매개변수는 이론적 최대 체장 ($L_{\infty}$)은 61.3 cm, 성장계수 (K)는 가숭어 전체 $0.29yr^{-1}$, 체장이 0일 때 이론적 연령 ($t_0$)은 - 0.05 yr로 추정하였다. 해역별 가숭어의 성장을 비교해 본 결과, 가숭어는 하구역에서 주로 성육을 하며, 연령과 성장매개변수를 제공함으로써 추후 가숭어 자원생태 연구에 도움이 될 것으로 판단된다.

• 수산해양기술연구
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• 제26권4호
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• pp.309-316
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• 1990

1986년 5월부터 1988년 4월까지 정기 채집한 545 개체와 정점 채집한 525개체등 합계 1,070개체의 이석을 적출하여 연령 형질로서 사용했다. 이석 연근의 투명대와 불투명대의 관찰 결과, 투명대 형성개시시기는 5월이며, 불투명대 개시시기는 1월이었다. 투명대와 불투명대는 년1회 형성되므로 투명대 외연을 연령표시로서 이용했다. 이석 반경과 표준체장의 관계식으로부터 각륜 형성시의 체장을 역산했다. Lee 현상은 보이지 않았으며, 이석반경과 표준체장은 곡선개계를 나타냈다. 각 연령 형성시의 계산체장은 이용하여 von Bertalanffy 성장식을 다음과 같이 구했다. Male ;Lt=376.9{1-exp[-0.303(t-0.202)]} Female ;Lt=255.7{1-exp[-0.505(t-0.149)]} 여기서, Lt는 표준체장(mm)이고, t는 연령이다.

• 수산해양기술연구
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• 제44권4호
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• pp.312-322
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• 2008

The age and growth of the sandfish, Arctoscopus japonicus were investigated from samples of the eastern sea danish seine and gill net fishery in the East Sea of Korea from February, 2004 to December, 2007. Ages were determined from annuli in otoliths and annuli were formed between December and February once a year. Also, the main spawning period was estimated to be between December and January, thus rings were considered to be annual marks. For the relationship between fork length and total weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length. The relationship between fork length and total weight were $TW=0.0083FL^{3.01}(R^2=0.966)$ for female and $TW=0.0079FL^{3.04}(R^2=0.969)$ for male. The variability in growth was constant as a function of age, revealing an additive error structure. The von Bertalanffy growth parameters estimated by a non-linear method were $L_{\infty}=31.6cm$, K=0.266/year, $t_0=-0.835$ years for female and $L_{\infty}=27.7cm$, K=0.273/year, $t_0=-0.806$ years for male. Growth at age between male and female had a significant difference(P<0.001).

• Journal of Ecology and Environment
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• 제44권3호
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• pp.185-195
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• 2020

Background: The flathead grey mullet Mugil cephalus has the widest distribution among mugilid species. Recent studies based on mitochondrial DNA sequences showed that the species comprises at least 14 different groups, three of which occur in the northwest Pacific. We analyzed the otolith microchemistry of M. cephalus at several locations in Korea to improve understanding of migration pattern and population origin. Results: We collected 123 sagittal otoliths from seven locations and determined their concentrations of eight elements (⁷Li, ²⁴Mg, ⁵⁵Mn, ⁵⁷Fe, ⁶⁰Ni, ⁶³Cu, ⁸⁸Sr, and ¹³⁸Ba) using laser ablation inductively coupled plasma mass spectrometry. Mean otolith elemental ratios differed significantly among the locations. The Sr:Ca, Fe:Ca, and Ba:Ca ratios were significantly higher than others, and useful chemical signatures for investigating the habitat use of M. cephalus populations. We identified five diverse and complicated migration patterns using the otolith data that we collected: estuarine resident (type I), freshwater migrant (type II), estuarine migrant (type III), seawater resident (type IV), and seawater migrant (type V). A canonical discriminant analysis plot revealed separation of two groups (type II in the Yellow Sea vs. other types in remaining locations). Two locations on Jeju Island, despite their close proximity, had fish with quite different migration patterns, corroborating previous molecular studies that distinguished two groups of fishes. Conclusion: We successfully showed that the migration patterns of the Korean mullet varied by location. Only fish from the western sector of Jeju had a unique migration pattern, which is likely confined population in this area. Among the eight otolith elements measured, the Sr:Ca ratio was found to be the best indicator of migration pattern and population origin.