• Journal of the korean society of oceanography
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• 제32권2호
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• pp.63-68
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• 1997

Stable isotope profiles with fine-scale resolution were constructed from the fossil mollusk shells, Mercernaria mercernaria, obtained from the late Pleistocene transgressive deposits of Gomez Pit, Virginia, USA. Incremental sampling were made along the axis of maximum growth to provide high-resolution ${\delta}^{18}$O and ${\delta}^{13}$C records. The ${\delta}^{18}$O shell profiles exhibit a series of pronounced cycles in the overall amplitude, corresponding to strong seasonal variations in temperature, which is apparently positive environmental variable. Contrasts between the patterns of ${\delta}^{18}$O and ${\delta}^{13}$C profiles reflect the relationship influencing the seasonal carbon cycling in the shallow marine environment. Positive anomalies of the ${\delta}^{13}$C values during the summer were observed to be out of phase with the ${\delta}^{18}$O profile. Such relatively heavier carbon source may be alternated due to seasonal methanogenesis during the summer. A hypothesized methane-based system may be operated in the shallow and marginal marine environment, resulting in a ${\delta}^{13}$C enriched bicarbonate pool, in which the heavier isotope seems to be incorporated to the shell carbonate.

• Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.336-343
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• 2023

This study aimed to know the response of deep-sea squid Sthenoteuthis oualaniensis to the light colors of the artificial bait. This experiment used the commercial artificial flashlight baits commonly sold in the fishing shop. The bait has several different light color combinations. The light colors were modified into several light colors by inactivating certain colors and used as treatments. The study is expected to be able to find flashlight bait's most effective color for squid fishing. We applied red-green, green, blue, and commercial bait lights in this study. Each treatment has 3 replications. The effect was expressed as the amount of squid caught. Data were analyzed by one-way analysis of variance. Results showed a significant effect on the number of squid catches. There was significantly different squid catches among the treatments. It indicates that this artificial flashlight bait could be developed to maximize squid catches. This finding can be used for the local fishermen's income and the squid fisheries development.

• 한국해양학회지
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• 제30권5호
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• pp.480-492
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• 1995

제주도 해안을 따라 협재, 애월, 이호, 삼양, 함덕, 세화, 표선, 중문, 화순지역 에 분포하는 해빈퇴적물의 구성성분과 그들을 조절하는 요인들을 알아보기 위하여 이 들 퇴적물에 대한 암석학적인 조사를 실시하였다. 각 지역 퇴적물의 평균입도는 각각 협재 2.2$\psi$, 애월 0.8$\psi$, 이호 1.4$\psi$, 삼양 2.4$\psi$, 함덕 1.6$\psi$, 세화 $1.5\psi$, 표선 2.1 $\psi$, 중문 0.4, 화순 0.9$\psi$로 대개 0.4-2.4$\psi$정도이며, 분급도는 표선과 화순지역의 퇴 적물만이 불량하고 애월과 중문지역은 보통이며 나머지 지역은 비교적 양호하다. 각 지역별로 퇴적물을 이루는 주 구성성분들을 살펴 보면, 백색을 띠는 협재, 애월, 함 덕, 세화, 표선지역의 해빈 퇴적물은 탄산염광물로 각질을 이루고 있는 연체동물 (mollusk)과 홍조류(red algae)의 각질파편들이 85%이상으로 포함되며, 흑색을 띠는 이호, 삼양, 화순지역은 화산암암편(rock fragment)이 우세하게 나타난다. 특히, 해빈 퇴적물이 비교적 백색을 띠는 탄산염입자가 우세한 지역 중에서 중문지역의 해빈퇴적 물내에는 화산암 암편의 함량이 다른 지역들 보다 더 높게 나타나며 요선지역에서는 탄산염입자의 암편(intraclast)이 우세하게 나타난다. 입자의 크기에 따른 생물들의 퇴적물에 대한 기여도를 살펴 보면 1-2$\psi$의 크기를 가진 입자들은 주로 석회조류로 이 루어져 있으면, 2-3$\psi$의 입자들은 주로 연체동물의 파편으로 구성된다. 특히, 삼양지 역은 0-1$\psi$를 이루는 구성성분 중 태선류(bryozoan)가 거의 48%를 구성하고 있는 것이 특징이다. 해빈퇴적물의 구성성분을 조절하는 요인들은 하천에 의한 화산암암편의 공 급량, 제주도 해안에 따라 해빈 주변에 분포하는 주변암의 암질(lithology), 연안류 (longshore current)의 방향 및 폭풍의 영향들이 있다. 이호와 삼양지역은 주변에 많 이 분포하는 하천의 발달로 하천을 통하여 공급된 화산암암편의 양이 다른 지역보다 상대적으로 많아 해빈퇴적물이 흑색도 띠며, 그 외의 지역에서는 화산암암편의 공급이 상대적으로 적고 탄산염입자의 공급이 활발하여 해빈퇴적물이 백색을 띠는 것으로 생 각된다. 특히, 중문지역에서는 화산암암편이 주변 하천으로부터 공급되었을 뿐만 아니 라, 이 지역들의 주변에 분포하는 응회암으로부터 폭풍의 영향에 의한 일부 공급되었 을 것으로 생각된다. 또한 표선지역의 해빈퇴적물에 많이 포함되어 있는 탄산염입자의 암편은 천해 교질작용에 의한 고화된 퇴적물이 침식되어 생성된 것으로서, 이는 표선 부근의 천해에서 활발한 천해교질작용이 일어나고 있음을 시사한다.

• Ocean and Polar Research
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• 제44권4호
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• pp.331-338
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• 2022

The high latitude scleractinian coral Alveopora japonica Eguchi, 1965 occurs in high density in the shallow rocky subtidal in Jeju Island, forming coral carpets. Despite its ecological role providing a unique habitat for other benthic organisms, the benthic fauna associated with the A. japonica coral carpet is poorly known. To identify fauna associated with the coral carpet, we explored three sites dominated by A. japonica and one control site on northwestern Jeju Island in May 2013. Using SCUBA, we collected A. japonica and the epibenthic mega-fauna associated with the colonies in 1×1 m² and identified them to the species level. At a depth of 10 to 15 m, A. japonica colonies heavily covered the seafloor, forming a layer called a coral carpet, with a density of 94 (Keumneung-ri), 133 (Biyangdo), and 155 (Gwidok-ri) colonies/m². Thirty-four molluscan species were identified from the four sites, including 20 bivalves and 14 gastropods. The coral carpets were enriched with sessile bivalves compared to the control site, as we identified twenty bivalve and eight gastropod species from the coral carpets. Most bivalve species associated with the coral carpets had tropical-subtropical affinities, while gastropods were mainly subtropical and subtropical-low boreal species. Leiosolenus lischkei M. Huber, 2010, in the family Mytilidae and Barbatia steamsi (Pilsbry, 1895), in the family Arcidae, were the two most abundant bivalve species in the coral carpet, L. lischkei being a borer, and B. stearnsi a nestler. The tropical to subtropical Pacific star shell Astralium haematragum (Menke, 1829)was the most abundant gastropod at the study sites. The bivalves and gastropods associated with the coral carpet were small-sized juveniles or sub-adults, suggesting that the coral carpet provides a micro-habitat for the bivalves and gastropods.

• Fisheries and Aquatic Sciences
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• 제8권2호
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• pp.76-82
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• 2005

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components C1, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to $492\;\mu{g}$ STXeq/100 g in mussels and 0 to $48\;\mu{g}$ STXeq/100 g in oysters. Mussels at Gijang and Sujeong-ri contained the most PSP toxin contents ($492\;\mu{g}\;STXeq/100\;g\;and\;252\;\mu{g}\;STXeq/100\;g,\;respectively$), exceeding the quarantine level ($80\;\mu{g}$ STXeq/100 g). Their dominant toxin components were C2, C1, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in AZexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.

• 한국수산과학회지
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• 제54권5호
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• pp.685-690
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• 2021

Harmful shell-boring species of the genus Polydora (Polychaeta: Spionidae) were frequently reported from commercially important mollusk species in Korea, Japan and China. The traditional approach based on the morphological characteristics showed limitations for species discrimination among shell-boring species. Therefore, DNA barcoding was adopted to identify Polydora species using molecular markers. Two Polydora species (P. haswelli and P. hoplura) in abalone shells were reported from our previous molecular phylogenetic study. In this study, we additionally reported the presence of shell-boring Polydora haswelli in commercially sold shellfish. The taxon-specific cox1 marker used in this study successfully allowed the isolation of P. haswelli from cockle Scapharca subcrenata, mussel Mytilus galloprovincialis, oyster Crassostrea gigas and scallop Argopecten irradians. Polydora hoplura was not found in these shellfish species. The genetic variations were found on the intraspecific level of P. haswelli and the same genotype was also detected in different shellfish species. This result can provide information on a new host and accurate parasitic Polydora species. Moreover, this report can be used as the biodiversity data of Polydora species on the invasion and transition of harmful Polydora species in mollusk aquaculture farms.

• 한국해양학회지:바다
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• 제10권2호
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• pp.124-128
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• 2005

한국 주변해역의 해양시료에서 측정된 탄소동위원소 연대 값을 실제 역년(calendar age)값에 가깝게 변환하기 위하여 국립수산과학원(NFRDI)에서 제공한 핵실험 이전인 1942년에 한국 연안에서 채취한 2종의 연체동물 패각 시료를 이용하여 marine reservoir correction$({\Delta}R)$ 값을 측정하였다. 남서해안에서의 측정된 ${\Delta}R$ 값은 $-117\pm45\;^{14}C\;yr$, 남동해안에서 측정된 값은 $-160\pm35\;^{14}C\;yr$로 계산되었다. 이 값들은 황해의 중국연안에서 측정된 값들의 범위에 속하는데 이는 중국과 한국 연안해역에서 reservoir $^{14}C$ age가 지구규모의 해양 평균 reservoir $^{14}C$ age보다 적은 값을 갖고 있음을 말한다. 이들 지역의 낮은 ${\Delta}R$ 값은 아마도 담수유입의 영향을 반영하는 것으로 생각된다. 본 연구에서 제시된 ${\Delta}R$값은 한국 주변해역에서 측정된 탄소동위원소 연대 값을 실제 역년 값에 가깝게 변환시킬 수 있도록 도움을 줄 것이다.

• Fisheries and Aquatic Sciences
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• 제20권6호
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• pp.8.1-8.18
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• 2017

Background: Metallothionein (MT) is a multifunctional protein playing important roles in homeostatic regulation and detoxification of metals. Mollusk species have been considered as useful sentinel platforms for MT-based biomarker approaches, and they have been reported to display an extraordinary structural diversity of MT proteins. However, potential diversity of molluskan MTs has not been fully explored and recent updates have suggested the need of revision of evolutionary hypothesis for molluskan MTs. Results: Based on bioinformatic analysis and phylogenetic evidences, novel divergence mechanisms and paths were hypothesized in both gastropod and bivalve MT groups. Our analyses are suggestive of the taxon- or lineage-specific domain multiplication/duplication from the ancestral or prototypic MT. Diversification and selection of molluskan MTs might be driven by the needs for acquiring metal selectiveness, specialized novel function, and improved capacity of metal detoxification under environmentally stressed conditions. Conclusion: The structural diversity and variations of molluskan MTs are significantly larger than previously understood. Undoubtedly, molluskan MTs have undergone dynamic divergent processes in their evolutionary histories, giving rise to the great diversity of domain structures in extant MT isoforms. Novel evolutionary paths for molluskan MTs newly proposed in this review could shed additional light onto the revision of the hypothesis for evolutionary differentiation of MTs in the molluskan lineage.

• 수산해양기술연구
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• 제45권1호
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• pp.1-13
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• 2009

Experimental fishing operation by the shrimp beam trawl was carried out to investigate the bycatch in order to develop the selective fishing gear of the shrimp beam trawl fishery. The experimental trawling was performed by the prototype fishing gear in coast sea of Boryeong, Buan, Kangjin, Tongyeong and Geoje from 30 April to 13 November 2005. Bycatches of the experimental trawling were analyzed species composition, total length composition. The results obtained can be summarized as follows; Target fishes caught by the shrimp beam trawl were Palaemon gravieri, Crangon Hakodatei, Trachysalambria curvirostris, Parapenaeopsis tenellus, Rhynchocinetes uritai and Matapenaeus joyneri. And their fishing rate and total length range were 50.0%, 46.0%, 2.6%, 0.4%, 0.3%, 0.3% and 40-80mm, 40-80mm, 120-150mm, 60-80mm, 60-80mm, 60-120mm respectively. Bycatches caught by the shrimp beam trawl consisted of fishes of 30 kinds, 6 kinds of mollusk, 5 kinds of shellfishes and 3 kinds of crabs. The main fish was Engraulis japonicus, Platycephalus indicus, Paralichthys olivaceus, Leiognathus nuchalis and Conger myriaster, their occupied rate were 47.0%, 16.6%, 13.6%, 5.5%, 2.7% respectively, and their total length range were 60-150mm, 80-410mm, 80-600mm, 30-80mm and 150-460mm respectively. A number bycatch rates of shrimp beam trawl fishery were 99.7% in Buan, 60.0% in Kangjin, 14.6% in Boryeong, 10.6% in Tongyeong and 2.7% in Geoje, The weight bycatch rate were 99.9% in Buan, 75.1% in Kangjin, 57.1% in Tongyeong, 47.4% in Boryeong and 15.4% in Geoje.

• 수산해양기술연구
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• 제53권4호
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• pp.349-356
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• 2017

The catch composition of commercially important species of the stationary lift net at Barangay Gines, Miagao, Iloilo, the Philippines was investigated from December 2013 to May 2014 during the different phases of the moon. A total of 486 kg of fish coming from 12 different genera, including mollusk and crustaceans, was caught and identified from the catch of the stationary lift net. Among the 12 genera identified from the catch of stationary lift net, anchovy (Stolephorus), sardines (Sardinella), squid (Loligo) and mysid shrimp (Acetes) were considered to be commercially important due to their value. Acetes catch was highest during the new moon in the month of January. Loligo catch was also high during the new moon except in the month of May. Stolephorus catch was also highest during the new moon except in the month of January. Sardinella catch was highest during the first quarter in the month of February. Full moon had the lowest catch all throughout the duration of the study while new moon had the highest catch during December 2013 to March 2014 and first quarter was the highest in the months of April and May.