• Title/Summary/Keyword: White Sea

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Distribution of Whales and Dolphins in Korean Waters Based on a Sighting Survey from 2000 to 2010 (목시조사(2000-2010)에 의한 한국 연안 고래류의 종류 및 분포)

  • Sohn, Hawsun;Park, Kyum Joon;An, Yong Rock;Choi, Seok Gwan;Kim, Zang Geun;Kim, Hyun Woo;An, Du Hae;Lee, Young Ran;Park, Tae-Geon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.45 no.5
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    • pp.486-492
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    • 2012
  • In the late 1970s, the National Fisheries Research & Development Institute (NFRDI) started cetacean research to submit the Korean whale catch record to the International Whaling Commission. This continued until the moratorium on commercial whaling in 1986. The NFRDI resumed cetacean research with a pilot whale sighting survey in 1999. Subsequently, the NFRDI has conducted 53 cetacean sighting surveys within the Korean exclusive economic zone between 2000 and 2010. The surveys took a total of 760 days and cruising for 23,866 nautical miles. The finless porpoise Neophocaena asiaeorientalis was sighted most frequently (735 times), followed by the minke whale Balaenoptera acutorostrata (396 times), the long-beaked common dolphin Delphinus capensis (102 times), and the Pacific white-sided dolphin Lagenorhynchus obliquidens (27 times). Minke whales were distributed in the Yellow Sea and coastal area of the East Sea from spring to fall. Pacific white-sided dolphin sightings were restricted to the middle and upper coastal areas of the East Sea in summer. Common dolphins were sighted from east of the southern coast to the eastern coast of the Korean Peninsula from spring to fall. Finless porpoise occurred in all Korean coastal areas, except the middle and upper eastern coast.

Detection of Sequence-Specific Gene by Multi-Channel Electrochemical DNA Chips

  • Zhang, Xuzhi;Ji, Xinming;Cui, Zhengguo;Yang, Bing;Huang, Jie
    • Bulletin of the Korean Chemical Society
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    • v.33 no.1
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    • pp.69-75
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    • 2012
  • Five-channel electrochemical chips were fabricated based on the Micro-electromechanical System (MEMS) technology and were used as platforms to develop DNA arrays. Different kinds of thiolated DNA strands, whose sequences were related to white spot syndrome virus (WSSV) gene, were separately immobilized onto different working electrodes to fabricate a combinatorial biosensor system. As a result, different kinds of target DNA could be analyzed on one chip via a simultaneous recognition process using potassium ferricyanide as an indicator. To perform quantitative target DNA detection, a limit of 70 nM (S/N=3) was found in the presence of 600 nM coexisting noncomplementary ssDNA. The real samples of loop-mediated isothermal amplification (LAMP) products were detected by the proposed method with satisfactory result, suggesting that the multichannel chips had the potential for a high effective microdevice to recognize specific gene sequence for pointof-care applications.

Whitening Method for Performance Improvement of the Matched Filter in the Non-white Noise Environment (비백색 잡음 환경에서 정합필터 성능개선을 위한 백색화 기법)

  • Kim Jeong-Goo
    • Journal of Korea Society of Industrial Information Systems
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    • v.11 no.3
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    • pp.15-19
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    • 2006
  • In shallow water active sonar environment, reverberation which is a non-white noise is one of the main source of performance degradation of target detection. In this case, the received signal is whitened before applying matched filter known as an optimum filter in the presence of white noise. However implementation of this method is very difficult because of the non-stationary characteristic of reverberation. Traditionally reverberation is assumed local stationary. In this paper, we estimate a range of stationary of reverberation signal, and then propose a pre-whitening method which improve the performance of pre-whitening block normalized matched filter in presence of non-white reverberation noise. Proposed whitener shows better whitening performance than traditional whitener because it use later as well as before reverberation of target signal. To evaluate performance of the proposed whitener, an actual measurement data sampled at the East-Sea is used for computer simulation. The target detector with new whitener is shown better performance than detector with traditional whitener.

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Effects of Salinity and Standard Toxic Metal(Cu, Cd) on Fertilization and Embryo Development Rates in the Sea Urchin(Hemicentrotus pulcherrimus) (염분과 표준 독성물질(Cu, Cd)이 말똥성게(Hemicentrotus pulcherrimus)의 수정 및 배 발생률에 미치는 영향)

  • Hwang, Un-Ki;Rhee, Choong-Won;Kim, Kwang-Seob;An, Kyoung-Ho;Park, Seung-Youn
    • Environmental Analysis Health and Toxicology
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    • v.24 no.1
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    • pp.9-16
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    • 2009
  • Effects of salinity and standard toxic metals on fertilization and embryo development rates were investigated in the sea urchin, Hemicentrotus pulcherrimus. Spawning was induced by injecting $1{\sim}2$ mL of 0.5 M KCl into the coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. The fertilization rate was below 30% when salinity was 20 psu and lower, but was almost above 90% when salinity was 25 psu and higher. The embryo development rate was below 60% when salinity was 25 psu and lower, but was above 80% when salinity was between 30 and 35 psu. The fertilization and embryo development rates in the control condition(not including Cu and Cd) were greater than 90%, but decreased a high negative correlation with the increasing of Cu(r=-0.80, r=-0.78) and Cd(r=-0.90, r=-0.82) concentrations, respectively. The fertilization and embryo development rates were significantly inhibited in the addition of Cu($EC_{50}$=17.30 ppb, $EC_{50}$=10.32 ppb) and Cd($EC_{50}$=364.57 ppb, $EC_{50}$=244.04 ppb), respectively. These results suggest that salinity concentrations for successful fertilization and normal embryogenesis of H. pulcherrimus are above 25 psu and 30 psu, respectively, and the biological assays of fertilization and embryo development rates using H. pulcherrimus are useful methods for the ecological toxicity test of marine pollution elements.

Currant Status of Detection of Aquatic Animal Pathogens in Cultured Juveniles for Stock Enhancement from 2009 to 2012 (방류용 수산종묘의 수산생물 병원체 검출 동향 (2009~2012))

  • Cho, Mi Young;Won, Kyoung Mi;Han, Hyun-Ja;Kim, Hyeun Jeong;Jee, Bo-Young;Kim, Seok-Ryel;Lee, Soon Jeong;Kim, Jin Woo;Park, Myoung Ae
    • Journal of fish pathology
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    • v.26 no.2
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    • pp.99-110
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    • 2013
  • Hatchery-reared seeds provides a key source of animal protein for human consumption and restocking for fishery management. For stock enhancement program, we have inspected the hatchery-reared seeds of 33 species in 2009, 44 species in 2010, 43 species in 2011 and 46 species in 2012 for legally designated diseases. Results showed that abalone was the most abundant in the marine species group and then sea cucumber, olive flounder, rockfish and swimming crab were followed. Crucian carp was the most abundant and then mandarin fish, Korean bullhead, melanian snail and Chinese mitten crab were followed in the freshwater species group. The number of inspection for black sea bream, rock bream, scorpionfish, black scraper, and eel has continuously decreased for four years. The inspection for flathead mullet has been carried out only in 2009. The total number of inspection cases for eight pathogens in this study were 8,476 and disqualification cases were 56 (0.67%) by detection of aquatic animals pathogens such as koi herpesvirus, white spot syndrome virus, red sea bream iridovirus or viral haemorrhagic septicemia virus.

Aquatic animal health management in stock enhancement (방류용 수산종묘의 질병 관리에 대한 고찰)

  • Seo, Jang-Woo;Cho, Mi-Young;Kim, Jin-Woo;Park, Gyeong-Hyun;Jee, Bo-Young;Choi, Dong-Lim;Park, Myoung-Ae;Oh, Myung-Joo
    • Journal of fish pathology
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    • v.23 no.1
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    • pp.85-98
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    • 2010
  • Ministry of Agriculture, Fisheries and Food (MAFF) and National Fisheries Research and Development Institute (NFRDI) have inspected the hatchery-reared seeds of 22 marine species and 11 freshwater species for aquatic animal diseases in stock enhancement program in 2009. Results showed that total 12 local selfgovernments have been restocking the sea with cultured juveniles. Gyeongsangnam-do, Jeollanam-do, Jejudo and Chungcheongnam-do have a preference for marine species seeds to freshwater species. On the contrary, freshwater species were released mostly in Gyeonggi-do, Jeollabuk-do and Chungcheongbuk-do. In the marine species group, abalone was the most abundant as 24.5%, and then sea cucumber (15.2%), olive flounder (11.5%), swimming crab (5.6%), black sea bream and rockfish (6.8%), rock bream (5.1%), black rockfish (4.6%) and scorpionfish (4.5%) were followed. Crucian carp was the most abundant as 19.4%, and then eel (17.0%), Korean bullhead (12.3%), melanian snail (12.0%), catfish (8.4%) were followed in the freshwater species group. The total number of inspection cases in this study were 1,080 and disqualification cases were 19 by detection of aquatic animals pathogens such as red sea bream iridovirus (RSIV), koi herpesvirus (KHV) or white spot syndrome virus (WSSV).

Status of the Cetacean Bycatch near Korean Waters (한국 연안 고래류의 혼획 현황)

  • Kim, Doo Nam;Sohn, Hawsun;An, Yong-Rock;Park, Kyum Joon;Kim, Hyun Woo;Ahn, So Eon;An, Du Hae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.46 no.6
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    • pp.892-900
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    • 2013
  • In 2011, the system for conserving and managing cetacean resources in Korea changed. The status of the cetacean bycatch was analyzed using a distribution certificate that was issued by the coast guard. During 2011.2012, 12 species were bycatch in Korean waters: three species of baleen whale and nine species of dolphin. The finless porpoise (Neophocaena phocaenoides) was the dominant species, followed by the common dolphin (Delphinus delphis), harbor porpoise (Phocoena phocoena), and Pacific white-sided dolphin (Lagenorhynchus obliquidens). Among the baleen whales, the common minke whale (Balaenoptera bonaerensis) was first and Bryde's (Balaenoptera edeni) and humpback (Megaptera novaeangliae) whales appeared in the Korea Strait and East Sea, respectively. Among the dolphins, the finless porpoise ranked first in the Yellow Sea. The common dolphin, Pacific white-sided dolphin, and harbor porpoise were more frequent in the East Sea than in other waters. The cetacean bycatch was caused mainly by pots, set nets, gill nets, and stow nets. Among the three species of baleen whale, the common minke whale was caught by pots and set nets, and comprised over 68.9% of the total bycatch in 2011 and 56.2% in 2012. Comparing the bycatch caused by fishing gears by area in 2011 and 2012, 97.9% and 99.6%, respectively, of the finless porpoise bycatch in the Yellow Sea was by stow nets. In the Korea Strait, trawl bycatch comprised 67.3% in 2011 and 73.0% in 2012, followed by gill nets, set nets, and pots targeting finless porpoise and common minke whales. In the East Sea, gill nets were responsible for 46.7% in 2011 and 61.2% in 2012, followed by set nets and pots.

Trypsin Activity in the Digestive Organs and Gastric Evacuation Rate of Litopenaeus vannamei at the Different Rearing Water Temperatures (사육수온에 따른 흰다리새우 Litopenaeus vannamei 소화기관의 trypsin 활성과 배설률)

  • Kim, Su-Kyoung;Kim, Bong-Rae;Kim, Dae-Hyun;Kim, Jong-Seek;Jang, In-Kwon
    • Journal of Aquaculture
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    • v.21 no.3
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    • pp.184-189
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    • 2008
  • Tryptic enzyme activities in the digestive glands (hepatopancreas) and digestive tracts of Pacific white shrimps Litopenaeus vannamei were assayed at three water temperature regimes. At $26^{\circ}C$, trypsin activity in the hepatopancreas was 200% higher than at $23^{\circ}C$ and 300% higher than at $20^{\circ}C$. The highest foregut trypsin activity levels showed no significant difference in the temperature regimes, but the time between peaks in foreguts and midguts shortened at higher temperature. In the midgut, the level of enzyme activity was highest at $26^{\circ}C$ regardless of the amount of ingested feed. The ratio of foregut and/or midgut dry weight to the body wet weight indicated feed movement through the digestive track directly and gave accurate account about the feeding mechanism. Maximum feed ingestion in the foregut was equivalent to 0.6% of the body weight (wet weight) at $23^{\circ}C$, 0.4% of the body weight at $20^{\circ}C$, and 0.5% of the body weight at $26^{\circ}C$. In view of the temperatures chosen for this study, although maximum ingestion was observed at $23^{\circ}C$, the shrimps showed highest enzyme activity, but lowest feed retention time at $26^{\circ}C$ and lowest enzyme activity, but highest retention time at $20^{\circ}C$.

A study of response control on the passive coupling element between two parallel structures

  • Zhu, Hongping;Iemura, Hirokazu
    • Structural Engineering and Mechanics
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    • v.9 no.4
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    • pp.383-396
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    • 2000
  • A new structure-vibration-control approach is proposed which uses a passive coupling element between two parallel structures to reduce the seismic response of a system due to earthquake excitation. Dynamic characteristics of the two coupled single-degree-freedom systems subject to stationary white-noise excitation are examined by means of statistical energy analysis (SEA) techniques. Optimal parameters of the passive coupling element such as damping and stiffness under different circumstances are determined with an emphasis on the influence of the structural parameters of the system on the optimal parameters and control effectiveness. Numerical results including the root mean square values of the response due to the filtered white-noise excitation and the time-histories of response to El Centro 1940 NS excitation are presented.

A Study on the Denoising Method by Multi-threshold for Underwater Transient Noise Measurement (수중 천이소음측정을 위한 다중 임계치 잡음제거기법 연구)

  • 최재용;도경철
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.6
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    • pp.576-584
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    • 2002
  • This paper proposes a new denosing method using wavelet packet, to reject unknown external noise and white gaussian ambient noise for measuring the transient noise which is one of the important elements for ship classification. The previous denosing method applied the same wavelet threshold at each node of multi-single sensors for rejecting white noise is not adequate in the underwater environment existing lots of external noises. The proposed algorithm of this paper applies a modified soft-threshold to each node according to the discriminated threshold so as to reject unknown external noise and white gaussian ambient noise. It is verified by numerical simulation that the SNR is increased more than 25㏈. And the simulation results are confirmed through sea-trial using multi-single sensors.