• 제목/요약/키워드: Living Resources

검색결과 989건 처리시간 0.029초

Sex Differentiation and Early Gonadogenesis in Sebastes inermis Cuvier

  • Choi, Hee-Jung;Oh, Sung-Young;Myoung, Jung-Goo;Kim, Jong-Man;Hur, Jun-Wook;Park, Min-Ouk;Park, In-Seok
    • Ocean and Polar Research
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    • 제30권4호
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    • pp.401-406
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    • 2008
  • Early gonadal development and sexual differentiation of dark-banded rockfish (Sebastes inermis Cuvier) were followed from parturition to 400 days post parturition (dpp). During this period, average total length (TL) increased from 0.57 to 13.18 cm. Primordial germ cells (PGCs) were first detected at 0.68 cm TL (10 dpp). When fish reached 1.52 cm TL (50 dpp), initial stages of ovarian differentiation were identified by the presence of PGCs containing condensed chromatin and their transformation into meiotic oocytes. At 10.23 cm TL (300 dpp), the ovaries gradually developed into oocytes in the primary yolk stages. Ovary growth was rapid after sex differentiation, but testis tissue continued to multiply without growing until fish reached 6.97 cm TL (200 dpp), after which the production of spermatocytes, spermatogonia, and cyst cells was apparent. Histological analysis of gonadal structure suggested a gonochoristic sexual development pathway. Our analysis of the sex ratio at 400 dpp showed a significantly higher proportion of males.

제주도 근해에서 채집된 가시우럭(Liopropoma japonicum) 후기자어의 외부형태 관찰 (Description of a Postflexion Larva Specimen of Liopropoma japonicum (Döderlein) off Jeju Island, Korea)

  • 김성;유재명;이은경
    • Ocean and Polar Research
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    • 제26권4호
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    • pp.685-688
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    • 2004
  • The morphology of the post-larva of Liopropoma japonicum of the family serranidae is described from one specimen collected off Jeju Island ($32^{\circ}42'N,\;127^{\circ}45'E$) on May 3, 2001. The body is laterally compressed and caudal peduncle deep at 19.4 mm BL. Anus locates at a vertical through posteriormost(8th) dorsal-fin spine. Dorsal fin rays were VIII, 14; anal fin rays III, 10; pectroal fin rays 16; pelvic fin rays I, 5. A caudal fin is rounded. Length of elongate second and third dorsal-fin spines are 499% and 423% of the body length, respectively. A series of 50 sensory pores on body is elongated to caudal fin. Head spination is well developed. Melanophores are moderately large and dense in the head, and are small and rare in teh neck. Being freshly collected, the body color is yellowish-red and tail is semitransparent. The head is yellowish-red and the brain is dark-red.

Benthic Pollution Assessment Based on Macrobenthic Community Structure in Gamak Bay, Southern Coast of Korea

  • Koo, Bon-Joo;Je, Jong-Geel;Shin, Sang-Ho
    • Ocean and Polar Research
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    • 제26권1호
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    • pp.11-22
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    • 2004
  • Benthic pollution assessment based on macrobenthic community structure with environmental variables was carried out at twelve stations during two periods on a presumed pollution gradient in Gamak Bay. Univariate and multivariate methods were applied to investigate structural changes in the benthic communities. A clear gradient of pollution effects on the macrobenthic community was observed from the interior to the exterior of the bay. The community on the northwestern basin was severely disturbed due to a low level of hydrodynamics and a large amount of pollutant input from nearby cities. Exterior regions on the southern basin appeared to have the best benthic environmental characteristics among all stations according to most methods of analysis. Central ridge regions and two stations around the islets in the mouth of the bay exhibited intermediate levels of perturbation when compared to the more disturbed interior and undisturbed exterior regions. Pollution effects on the communities were attenuated at the southern area of the central ridge during spring compared to those of summer, where aquacultural farming was densely distributed. The environmental variables primarily correlated to the macrobenthic community structure were total organic carbon (C), organochlorine pesticides (OCPs), and tributyltins (TBTs), contents found on the surface sediment, as anthropogenic variables indicating organic materials.

자료정규화를 통한 농촌어메니티자원 조사표의 표준화 (Standardized Surveying Method of Rural Amenity Resources with Database Normalization Technique)

  • 김상범;이상영;정남수;이지민;조순재;이정재
    • 농촌계획
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    • 제10권4호
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    • pp.1-7
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    • 2004
  • In Korea, rural community has been becomming unstable by declining of agriculture. In order to solve this problem, there were some trials to activate rural communities by maintaining rural amenities. But, it is difficult to use rural amenities as a development factor to promote rural communities because there are few researches about quantifying rural amenities. In this study, a method fer quantifying rural amenities is suggested using database normalization technique. Previous thirty seven surveying items of rural amenity resources are formally reduced to five common surveying items, seven resources, and eleven surveying tables. Finally, big picture of rural amenity resource map with surveying data for rural development is suggested.

한국산 Opistognathidae (후악치과) 어류의 1 미기록종 Opistognathus iyonis에 대하여 (First Record of the Jawfish, Opistognathus iyonis (Opistognathidae, Perciformes) from Korea)

  • 명정구;조선형;김종만;김용억
    • 한국어류학회지
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    • 제11권2호
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    • pp.139-142
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    • 1999
  • 1998년 6월, 10월에 경상남도 통영군 좌사리제도 부근 수심 10~30 m에서 낚시로 채포한 한국 미기록 어종에 대하여 보고한다. 채집된 개체의 전장은 82.7 mm, 76.9 mm로서 체형은 원통형이며 등 쪽은 연록색 바탕에 불규칙한 갈색 무늬를 가지며 배 쪽은 엷은 황색을 띤다. 눈과 입이 매우 크며, 옆줄은 등지느러미 기저 부근에 위치하며 등지느러미의 줄기부 중앙 아래까지 이어진다. 우리 나라에서는 처음으로 발견된 이 종은 Opistognathidae (후악치과)에 속하고 Opistognathus iyonis로 동정되었으며, 입이 크고 등지느러미에 검은 점을 가진 특징으로서 "흑점후악치"로 명명하고자 한다.

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마이크로세틀라이트 마커 분석을 이용한 남서태평양 일대에 서식하는 남방톱날꽃게(Scylla serrata)의 유전적 다양성 (Genetic Diversity of the Mud Crab Scylla serrata in Micronesia based on Microsatellite Marker Analysis)

  • 장요순;이순길;노충환;오승용
    • Ocean and Polar Research
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    • 제31권4호
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    • pp.319-326
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    • 2009
  • Analysis of four microsatellite markers from Mud Crab Scylla serrata revealed that there is high level of genetic diversity within this species. Genetic diversity of S. serrata was calculated using allele diversity, observed heterozygosity, expected heterozygosity (Het-exp), polymorphic information content, gene differentiation and Nei's $D_{A}$ distance. Mean polymorphic information content value was 0.797, which reflected high level of polymorphism across the loci of S. serrata. The Palau population has the highest genetic diversity (Het-exp=0.871), while the Kosrae population has the lowest genetic diversity (Hetexp=0.806). However, the geographical genetic distance among S. serrata populations from Yab, Chuuk, Pohnpei, Kosrae, and Palau were low (0.2009${\sim}$0.3350). These results suggest that despite their wide distribution, S. serrata are no different in geographical genetic diversity within the five sampled locations.

퇴적촉진 구조물 설치에 따른 중형저서동물 군집구조 및 변동 (Community Structure and Spatial Variation of Meiobenthos Associated with an Artificial Structure)

  • 민원기;김동성;이재학
    • 한국수산과학회지
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    • 제39권spc1호
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    • pp.223-230
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    • 2006
  • We investigated the spring and summer community structure of meiobenthos in a tidal-falt near Iwon, Korea, in 2002 and 2003. In total, 12 meiofaunal groups were found in the study area among which nematodes were the most dominant. Benthic foraminiferans, harpacticoid copepods, polychaetes, and crustacean nauplli were also dominant groups at all sites. The total density of meiobenthos at each station was be 246-2,177 ind./$10cm^2$. As the depth of sediment increased, the density of meiobenthos at each station gradually decreased. Changes in the vertical distribution of meiobenthos in the study area occurred mainly near the sediment surface (0-1 cm). Generally, between spring and summer the density of nematodes increased, and the density of other dominant meiofaunal groups (benthic harpacticoids, crustacean nauplii, benthic foraminiferans) decreased near the sediment trap the control site of sediment traps compared to that at the control site. The results of cluster and multidimensional scaling plots indicate that the meiofaunal community changed following construction of a low artificial wood groin structure.

Morphological and Molecular Classifications of Genus Pholis

  • Lee, Sung-Hoon;Jang, Yo-Soon;Baik, Chung-Boo;Han, Kyeong-Ho;Myung, Jung-Goo;Lee, Jin-Hee;Choi, Sang-Duk;Kim, Seon-Jae;Kim, Jong-Oh;Hwang, Jae-Ho
    • Animal cells and systems
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    • 제13권4호
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    • pp.453-460
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    • 2009
  • Morphological and molecular classifications were attempted in an effort to establish species-specific classifications of three species of the genus Pholis in Korea; these species were subjected to morphological and molecular methodologies using body measurements, RFLP, RAPD, and phylogenetic trees using the nucleotide sequences of mitochondrial 16S and 12S ribosomal DNAs, cytochrome c oxidase I, and cytochrome b. The data demonstrated that the three species of genus Pholis are distinct from each other, both morphologically and genetically.