• 한국수정란이식학회지
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• 제28권1호
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• pp.73-78
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• 2013

The present study examined the histological characteristics of adult testis in the long-beaked common dolphin (Delphinus capensis) from Korean waters and the localization of DEAD-box polypeptide 4 (DDX4; a germ cell marker) and vimentin (a Sertoli cell marker) expression in the dolphin testis compared with that in terrestrial mammals, including dogs and rats. The seminiferous tubules of dolphin testis have very small or completely closed lumens, and spermatogenic cells and Sertoli cells within the tubules cannot be differentiated. Immunohistochemical analysis showed that, in the dolphin testis, DDX4- and vimentin-positive cells were scattered extensively within the tubule, whereas in the dog and rat testis, DDX4 immunoreactivity was localized in spermatogenic cells of the adluminal compartment, and vimentin immunoreactivity was localized in Sertoli cells of the basal compartment in the seminiferous epithelium. These results suggest that the histological characteristics of the seminiferous tubules in the dolphin testis differ from those of terrestrial species.

• Animal cells and systems
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• 제13권4호
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• pp.419-427
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• 2009

The Minke whale, Balaenoptera acutorostrata, is the smallest baleen whale in the suborder Mysticeti. Because this species inhabits coastal areas, it became a main target species of coastal small-type whaling in the North Atlantic and the Northwest Pacific Oceans, and the species' population size dramatically decreased because of over-exploitation. As a result, the International Whaling Commission declared a global moratorium on whaling and launched the development of a management procedure for protecting the whales. Morphological studies, whaling history analysis, and genetic studies conducted mainly by Japanese scientists showed the existence of one unique "E" stock that inhabits the waters around the Korean peninsula and mixes with the "O" stock in the southern part of the Sea of Okhotsk. We used the mitochondrial DNA control region polymorphism of 348 Minke whales bycaught or stranded in Korean waters from 30 October 1998 to 25 June 2005 to assess the whale population structure by year. The frequency of the 10 major haplotypes from the 40 identified haplotypes was not significantly different among groups, suggesting that a subpopulation was not present. A comparison of the genetic distances calculated with Tamura-Nei's method showed that the distances between groups were lower than those within groups, which suggests that there was no genetic difference in the Minke whale populations. The Fst comparison between groups and the phylogenetic tree constructed using the unweighted pair group method with arithmetic mean (UPGMA) and Neighbor Joining (NJ) method also detected no obvious sub-stock structure.

• 한국수산과학회지
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• 제40권4호
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• pp.201-209
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• 2007

Line transect sampling in a sighting survey is one of most widely used methods for assessing animal abundance. This study applied distance data, collected from three sighting surveys using line transects for finless porpoise that were conducted in 2004 and 2005 off the west coast of Korea, to four models (hazard-rate, uniform, half-normal and exponential) that can use a variety of detection functions, g (x). The hazard-rate model, a derived model for the detection function, should have a shoulder condition chosen using the AIC (Akaike Information Criterion), as the most suitable model. However, it did not describe a shoulder shape for the value of g(x) near the track tine and underestimated g (x), just as the exponential model did. The hazard-rate model showed a bias toward overestimating the densities of finless porpoises with a higher coefficient of variation (CV) than the other models did. The uniform model underestimated the densities of finless porpoise but had the lowest CV. The half-normal model described a detection function with a shape similar to that of the uniform model. The half-normal model was robust for finless porpoise data and should be able to avoid density underestimation. The estimated abundance of finless porpoise was 3,602 individuals (95% CI=1,251-10,371) inshore in 2005 and 33,045 individuals (95% CI=24,274-44,985) offshore in 2004.

• 한국수산과학회지
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• 제44권6호
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• pp.709-716
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• 2011

To investigate the distribution and migrations of sea turtles occurring in Korean waters, an adult female green sea turtle Chelonia mydas was tagged with a satellite transmitter and released at Busan in October 2009. The confirmation was made for the first time that the released green sea turtle migrated back to Korea after visiting Jeju Island and Japan for approximately 9 months. The green sea turtle spent the winter in Jeju and Japan because of low water temperatures in the East Sea and South Sea during winter months, which were not suitable for turtle survival. Compared with an immature green sea turtle that was released at Jeju Island, the adult green showed a markedly different migration pattern, suggesting that juvenile and adult greens move differently because of their peculiar life cycle and their stage of maturity, in addition to responses to temperature changes. Additional satellite tracking with increased representation of species, sexes and sizes of turtles, and regions is required to gather information on the distribution and movements of sea turtles in Korean waters.

• 한국어병학회지
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• 제26권3호
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• pp.289-294
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• 2013

제주도에서 좌초된 뱀머리돌고래, Steno bredanensis에서 Enterococcus faecium이 분리 되었다. E. faecium은 간, 비장, 신장, 심장, 폐에서 $1.54{\times}10^6$ cfu/g까지 분리 되었다. E. faecium KCCM 12118과 분리균주 사이의 효소 활성은 차이가 없었고 생화학적 특성은 같거나 유사하였다. 모든 분리균주는 6 종류 항균제에 대해 다재내성을 갖고 있었으나 chloramphenicol과 vancomycin에 대한 내성은 없었다.

• 한국수산과학회지
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• 제54권6호
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• pp.989-999
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• 2021

The sound of finless porpoises Neophocaena asiaeorientalis was recorded with an acoustic recorder to confirm their emergence in the South Sea of South Korea in February, June, and November 2020. Sea water temperature and salinity were also measured. In addition, a sighting survey was conducted to observe the behavior of the finless porpoises and the marine environment, and the clicks of the finless porpoises were recorded every day. The results showed that they always emerged in the survey area. The finless porpoises mainly foraged, whereas some played or rested. The water temperature range of areas where the finless porpoises emerged was 7.5-23.5℃. Assuming that the number of clicks corresponds to the number of finless porpoises, the finless porpoises emerged the most during spring. The emergence decreased during winter and was the lowest during autumn. The finless porpoises emerged more during the daytime than during the nighttime in all seasons, indicating a temporal difference in the usage of the survey area. This might be due to the movement of prey organisms according to regional characteristics. A long-term survey and research on habitat use and environment is needed to manage and conserve the finless porpoises.

• 한국해양바이오학회지
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• 제7권2호
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• pp.35-41
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• 2015

Whales are marine mammals that are fully adapted to aquatic environment. Whales breathe by lungs so they require adaptive system to low oxygen concentration (hypoxia) while deep and prolonged diving. However, the study for the molecular mechanism underlying cetacean adaptation to hypoxia has been limited. Hypoxia-inducible factor (HIF) is the central transcription factor that regulates hypoxia-related gene expression. Here we identified HIF-binding sites in whale genome by phylogenetic footprinting and analyzed HIF-target genes to understand how whales cope with hypoxia. By comparison with the HIF-target genes of terrestrial mammals, it was suggested that whales may retain unique adaptation mechanisms to hypoxia.

• 한국수산과학회지
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• 제54권4호
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• pp.517-525
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• 2021

Trawl fishing is a major concern worldwide, and there is considerable debate about its impact on marine ecosystems. In this study, we used the vessel monitoring system (VMS) data collected in the southwest Atlantic Ocean from 2016 to 2019 to estimate the fishing effort and trawled area. Spatial distribution of trawl activities according to the latitude and longitude and the hotspots where fishing was concentrated each year were identified. Trawling activities of the Korean vessels were mainly distributed between 40-52°S and 56-63°W. The species caught during the fishing period comprised five Cephalopoda, three Chondrichthyes, ten Osteichthyes, and other fish. The Argentine hake Merluccius hubbsi and Argentine shortfin squid Illex argentinus were the dominant species in the catch.

• 한국환경생태학회지
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• 제25권2호
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• pp.123-131
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• 2011

2007년 4월부터 5월까지 시험조사선을 이용하여 동해의 해양성 조류 분포조사를 실시하였다. 조사 기간 동안 동해 연안에서 총 10과 23종 1,379개체의 조류가 관찰되었으며, 이 중 6과 14종 1,324개체는 해양성 조류였다. 해양성 조류의 발견율은 2.5 birds $km^{-2}$였다. 가장 높은 발견율을 보인 종은 슴새(Calonectris leucomelas)로 전체 관찰개체수의 74.5%를 차지하였다. 이밖에 발견된 조류 중 1% 이상을 차지한 주요종은 바다쇠오리(Synthliboramphus antiquus)(8.3%), 아비(Gavia stellata)(5.0%), 제비갈매기(Sterna hirundo)(2.1%), 회색머리아비(Gavia pacifica) (2.0%), 괭이갈매기 (Larus crassirostris)(1.1%) 순으로 나타났다. 해양성 조류의 개체수는 동해 중남부 해역인 $36^{\circ}N{\sim}37^{\circ}N$ 사이에서 가장 많았으나 종다양도 지수(H')는 동해 남부 해역인 $35^{\circ}N{\sim}36^{\circ}N$에서 가장 높은 값을 보였다. 발견된 대부분의 종은 해안선에서부터 멀어질수록 발견율이 줄어들었다. 발견된 주요종 이외에도 뿔쇠오리(Synthliboramphus wumizusume), 흰부리아비(Gavia adamsii), 쇠부리슴새(Puffinus tenuirostris), 붉은발슴새(Puffinus carneipes)와 같은 희귀종을 관찰하였다. 본 조사와 동시에 행해진 밍크고래(Balaenoptera acutorostrata) 목시조사의 자료를 통해 볼 때 슴새의 분포 패턴과 밍크고래의 분포 패턴 사이에서 높은 상관관계를 나타냈다. 아비류(Gavia spp.)의 분포는 공간적으로 분리되는 양상을 보였다.

• 수산해양교육연구
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• 제28권3호
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• pp.861-871
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• 2016

The coastal water of Korean Peninsula is the major habitat for finless porpoises. However, hundreds of finless porpoises are currently caught incidentally by stow-net fishery every year. To prevent the mass mortality of finless porpoises and conserve marine animals, Busan Aquarium has been designated as a "Marine Life Ex-Situ Conservation Institution and Marine Animal Conservation Center," and Cetacean Research Institute, under the National Institute of Fisheries Science have started RRR (rescue, rehabilitation and release) project together since 2011. From 2012 to 2013, four individuals of finless porpoises had been rescued and two of them finally released to their original habitat after fully recovered in July 2013. As a result, according to growth curve of finless porpoise of Korea more than 140 cm of body length, 38 kg of total weight referred to adult, results of observation of the change in the hormone revealed that mating time of finless porpoises is January, Jun and July. To become the initial institution which rescues, treatment, husbandry and releases finless porpoise in Korea.