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Diet Composition of Bullet Mackerel, Auxis rochei (Risso, 1810) in the Coastal Waters of Iloilo, Philippines (필리핀 일로일로 연안해역에 출현하는 몽치다래(Auxis rochei)의 위내용물 조성)

  • Baeck, Gun Wook;Quinitio, Gerald F.;Vergara, Christopher J.;Kim, Hyeon Ji;Jeong, Jae Mook
    • Korean Journal of Ichthyology
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    • v.26 no.4
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    • pp.349-354
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    • 2014
  • The diet composition of bullet mackerel, Auxis rochei was studied using 200 specimens collected from December 2013 to May 2014 in the coastal waters of Iloilo, Philippines. The size of A. rochei ranged from 11.1 to 31.2 cm in fork length (FL). A. rochei was epipelagic feeder that consumed mainly fishes. In addition, A. rochei consumed shrimps, copepods, crab larvae, amphipods and cephalopods. The diet also included small quantities of stomatopods, bivalves, and ostracods. Also, analysis of the prey-specific abundance against the frequency of occurrence shows that A. rochei have a narrow food niche, and are specialized feeder with fish as their dominant prey. Although fishes were the primary in food consumed by all size class. The fishes gradually increased with body size.

Confirmation of carbamate pesticides by liquid chromatography coupled with electrospray ionization mass spectrometry (LC/MS를 이용한 카바메이트계 잔류농약 확인방법)

  • 박준조;금모래;고광춘;박병옥;이성식
    • Korean Journal of Veterinary Service
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    • v.25 no.1
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    • pp.23-29
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    • 2002
  • A method was developed to separate, detect and qualify aldicarb, bendiocarb, carbaryl, carbofuran, ethiofencarb, methomyl, methiocarb, propoxur in meats and fruits. Experimental beef and fork samples were fortified with 0.05mg/kg of carbamate pesticides for analysis. Carbamate-detected pear by HPLC fluorescence detector(HPLC/FLS) are extracted with acetonitril and refined by solid phase extraction(SPE) filled with aminopropyl-bonded silca, In the following step, the injected materials into LC/MS are analyzed to result in the fact that bendiocarb, carbaryl, carbofuran, ethiofencarb, methomyl, methiocarb, propoxur presents several sorts of fraction ions following with; [M+H]$^{+}$, [M+Na]$^{+}$,[M-CONH$CH_3$]$^{+}$, [M-OCONH$CH_3$]$^{+}$. In addition, ethiofencarb presents [M-SCH$_2$$CH_3$]$^{+}$ ion distinctive and aldicarb presents [M+Na]$^{+}$ and [M-OCONH$CH_3$]$^{+}$ ion which is the most decisive fraction ion for pesticides such as bendiocarb, carbaryl, carbofuran, ethiofencarb, methiocarb, methomyl, propoxur excluding [M+H]$^{+}$ ion. However, [M-OCONH$CH_3$]$^{+}$ and [M-OCONH$CH_3$]$^{+}$ fraction ion charactering carbamate pesticides are detected most efficiently with fragment voltage 50ev. As a result, for rluantitative analysis, [M+Na]$^{+}$ ion is the most decisive ion for detection of aldicarb and [M+H]$^{+}$ ion is the most decisive fraction ion for Pesticides such as bendiocarb, carbaryl, carbofuran, ethiofencarb, methiocarb, methomyl, propoxur. Carbaryl-detected pear by HPLC/FLS are analyzed by L/MS and the result shows that [M+H]$^{+}$ and [M-CONH$CH_3$]$^{+}$ ions charactering carbaryl are detected.ering carbaryl are detected.

Maturation and Spawning of Black Seabream Acanthopagrus schlegeli in the Southern Sea of Korea (한국 남해안 감성돔(Acanthopagrus schlegeli)의 성숙과 산란)

  • Kwon, Hyeok Chan;Zhang, Chang Ik;Shin, Young Jae;Kim, Kwang Hoon;Kim, Joo Il;Seo, Young Il
    • Korean Journal of Ichthyology
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    • v.21 no.2
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    • pp.93-99
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    • 2009
  • The maturation and spawning of Black seabream Acanthopagrus schlegeli were investigated using samples randomly collected in the Southern Sea of Korea from March 2007 to February 2008. The FL at 50% sex-changers maturity was estimated to be 26.7 cm. We estimated monthly changes in maturity stages and gonadosomatic index (GSI). The spawning period ranged from March to July, and the peak spawning occurred in May and June. The fecundity (F) was 839,600 eggs at 32.2 cm fork length (FL) to 2,894,913 eggs at 42.0 cm FL, and the relationship between FL and F was expressed as $F=1.264FL^{3.869}$ ($R^2=0.736$). The FL at 50% group maturity was estimated to be 25.8 cm for females and 19.0 cm for males. The sex ratio was 19.9% for female, 20.9% for early sex-changers, 28.7% late sex-changers, 30.5% for male.

A Study on Establishing Measurement of the Record Information Contents In Past History Commission (과거사 관련 위원회 기록정보콘텐츠 구축방안 연구)

  • Woo, Jee-Won;Lee, Young-Hak
    • Journal of Korean Society of Archives and Records Management
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    • v.11 no.1
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    • pp.67-92
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    • 2011
  • With the movement for complete liquidation of the part history began during participatory government, a special law for the liquidation of the past history was enacted and committees related to the past history have been established. Works related to the past history has relatively smoothly progressed even if there have been many obstacles, but as the duration for the special law reached its final point, committees related the past history came to the fork of a road. This study reflects on this reality and focuses on measures for application of the records collected by committees related to the past history and in this way, establish and selected the record information contents was established and selected. The users of the information was classified into professors, students, and history researchers and Committee for the Inspection of Damages by Compulsory Mobilization under Japanese Imperialism, Committee for the Inspection of Japan Collaborators, and Truth and Reconciliation Commission were selected for the committees related to the past history to establish the contents.

Improvement of Positioning Accuracy of Laser Navigation System using Particle Filter (파티클 필터를 이용한 레이저 내비게이션의 위치측정 성능 향상)

  • Cho, Hyun-Hak;Kim, Jung-Min;Do, Joo-Cheol;Kim, Sung-Shin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.21 no.6
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    • pp.755-760
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    • 2011
  • This paper presents a method for improving the positioning accuracy of the laser navigation. As a wireless navigation system, the laser navigation which is more flexible than a wired guidance system is used for the localization and control of an AGV(automatic guided vehicle). However, the laser navigation causes the large positioning error while the AGV turns or moves fast. To solve the problem, we propose the method for improving the positioning accuracy of the laser navigation using particle filter which has robust and reliable performance in non-linear/non-gaussian systems. For the experiment, we use the actual fork-type AGV. The AGV has a gyro, two encoders and a laser navigation. To verify the performance, the proposed method is compared with the laser navigation which is a product. In the experimental result, we verified that the proposed method could improve the positioning accuracy by approximately 66.5%.

Age and Growth Characteristic of Pacific Anchovy, Engraulis japonicus, in the Southern Waters of Korea Based on the Year Ring of Otolith and Collection Date (이석 윤문 및 채집시기를 이용해 분석된 남해 멸치(Engraulis japonicus)의 연령과 성장특성)

  • Lee, Hae Won;Hwang, Sun Do;Kim, Heeyong
    • Korean Journal of Ichthyology
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    • v.33 no.1
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    • pp.31-36
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    • 2021
  • In order to understand the age and growth characteristics of Pacific anchovy, Engraulis japonicus, the 506 otoliths of individuals collected in the southern waters of Korea in 2004 were analyzed. Monthly age of anchovies was estimated based on the age determined through the year rings and their collection date. The growth parameters obtained using the monthly folk lengths were a theoretical maximum body length of 132.9 mm, a growth coefficient of 0.1079/month and a theoretical age of 0.0262 month when the fork length is zero. The growth equation of von Bertalanffy presented by the growth parameters was Lt=132.9(1-e-0.1079(t-1.0262)). The estimation of growth parameters based on the monthly age established through year ring and collection date was deemed appropriate for understanding the growth characteristics of anchovies.

A Study of Growth and Age Structure for Chub Mackerel, Scomber japonicus Caught by a Large Purse Seine in the Korean Waters (한국 주변해역에서 대형선망으로 어획한 고등어(Scomber japonicus)의 성장과 연령구조 연구)

  • Jung, Kyung-Mi;Kim, Heeyong;Kang, Sukyung
    • Korean Journal of Ichthyology
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    • v.33 no.2
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    • pp.64-73
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    • 2021
  • We examined the growth and age structure for chub mackerel caught by a large purseseine in the Korean waters from January to December 2015. A total of 459 specimens were used for otolith analysis, ranging from 19.6 cm to 46.0 cm in fork length. Translucent zone was regarded as an annual mark, and age was counted using the information of the number of translucent zone, capture date, edge type of the otolith and nominal birthdate of 1 January. Annuli in otoliths were mainly formed in May, coinciding with the spawning season. Estimated ages were 0~6 years, and the von Bertalanffy growth models were not significantly different between male and female. Sex-combined growth model was obtained as FLt=39.3×{1-exp[-0.90×(t+0.033)]}. Among the chub mackerel caught in 2015, the age 2 group had the highest proportion (30.9%), and the age 0 to 2 group accounted for 88.5% of the total catch.

Optimizing selection of sexually mature Barbus altianalis for induced spawning: determination of size at sexual maturity of populations from Lake Edward and Upper Victoria Nile in Uganda

  • Aruho, Cassius;Ddungu, Richard;Nkalubo, Winnie;Ondhoro, Constantine Chobet;Bugenyi, Fredrick;Rutaisire, Justus
    • Fisheries and Aquatic Sciences
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    • v.21 no.11
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    • pp.34.1-34.13
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    • 2018
  • Sexual maturity ($L_{50}$), the length at which 50% of fish in a size class are mature, is a key aspect of domestication of new fish species because it guides the procedure for identification of appropriate broodstock size for artificial spawning. In this study, the $L_{50}$ was determined for 1083 Barbus altianalis samples obtained from Lake Edward and the Upper Victoria Nile. Gonads of freshly killed samples were examined macroscopically and verified with standard histological procedures for the maturation stages that were used to determine $L_{50}$. Oocytes and spermatogenic cell sizes were compared for fish obtained from both water bodies. Results indicated that there were no variations in macro gonad features observed for fish from Lake Edward and Upper Victoria Nile. Similarly, there were no significant differences in oocyte sizes (P > 0.05) between the two populations but significant differences in spermatogenic cell sizes were noted (P < 0.05) except for spermatozoa (P > 0.05). This however did not suggest peculiar differences between the two populations for staging the gonads. Consequently, no staging variations were suggested for both populations in determination of $L_{50}$. Sexual maturity was found in the same class size of fork length (FL) 20-24.9 cm and 35-39.9 cm for males and females from both water bodies, respectively. At this FL, however, males were too small, and for good selection of vigor broodstocks for spawning and conservation purposes, they are better picked from class size of 30-34.9 cm FL and above. These findings were crucial for integration of appropriate breeding size in spawning protocol by farmers and fisheries scientists conserving wild B. altianalis populations.

Diet Composition of Spanish Mackerel Scomberomorus niphonius, in the South Sea of Korea (한국 남해에 출현하는 삼치(Scomberomorus niphonius)의 위내용물 조성)

  • Lee, Ju Eun;Seong, Gi Chang;Kim, HeeYong;Moon, Seong Yong;Baeck, Gun Wook
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.5
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    • pp.808-813
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    • 2021
  • The diet composition of Spanish mackerel Scomberomorus niphonius, was investigated using 853 specimens collected using two-boat trawl, stow net, gill net and set net from January to December 2019 from the South Sea of Korea. The size of the specimens ranged from 25.2 to 114.8 cm in fork length. S. niphonius fed mostly on fishes. Its diets also included small quantities of shrimps, cephalopods, crabs, stomatopods, etc. Among them, Engraulis japonicus was the dominant species. The dietary composition of S. niphonius exhibited significant differences based on their size. The proportion of Trichiurus japonicus increased as body size of S. niphonius increased, whereas the proportion of E. japonicus decreased gradually. As the body size of S. niphonius increased, the mean weight of prey per the stomach (mW/ST) tended to increase significantly (one-way ANOVA, P<0.05).

Reproductive Characteristics of Pacific Anchovy Engraulis japonicus from the Southern Waters of Korea (남해안에 서식하는 멸치(Engraulis japonicus)의 산란 특성)

  • Moon, Seong Yong;Baeck, Gun Wook;Lee, Mi Hee;Kim, Heeyong;Jung, Kyung Mi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.6
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    • pp.927-937
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    • 2022
  • The reproductive characteristics of Pacific anchovy, Engraulis japonicus were investigated using samples randomly collected from the southern waters of Korea between January and December 2021. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), egg diameter, fecundity, and fork length (FL) at sexual groups maturity of 50%, 75% and 97.5%, and sex ratio (female:male). GSI value showed two peaks in May and August; however, microscopic analysis of E. japonicus gonad tissue revealed that the spawning period was from March to October. The main spawning seasons for the entire populations were from April to June and August to September. The overall sex ratio was female-biased (1 females, 0.89 male). The fecundity (F) of female anchovies ranged from 429 eggs at an FL of 8.0 cm to 13,824 eggs at an FL of 14.9 cm and the relationship between FL and F was 0.0788FL4.422. The FL at 50% group maturity was 8.26 cm for female anchovies. Based on the results, we suggest that the reproductive cycle in Pacific anchovies may be related to pulses in water temperature and the sexual cycle of the fish.