• Title/Summary/Keyword: Six species

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Seasonal Variation in the Species Composition of Bag-net Catch from the Coastal Waters of Incheon, Korea (인천연안 낭장망 어획물 종조성의 계절변동)

  • Song, Mi-Young;Sohn, Myoung-Ho;Im, Yang-Jae;Kim, Jong-Bin;Kim, Hee-Yong;Yeon, In-Ja;Hwang, Hak-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.4
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    • pp.272-281
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    • 2008
  • Seasonal and annual variation in the species composition of bag-net catch in the coastal waters of Incheon, Korea were examined from April 2000 to November 2004. To analyze seasonal variation of the fisheries data, we implemented a self-organizing map(SOM), an unsupervised artificial neural network, with the catch amount of 97 species. Over 5 years, we caught 68 species of fish, 23 species of crustaceans and six species of cephalopods. The total number of fish species were gradually increased during the study period. The number of species was higher during the spring than the autumn. The SOM identified four groups of the sampling months based on seasonal changes in communities. In the spring, the dominant species were Leptochela gracilis and Pholis fangi; whereas, in the autumn, Engraulis japonicus and Portunus trituberculatus were dominant species in bag-net catch. Our results will be used to estimate seasonal and annual variation in fisheries resources of Korean coastal waters.

Effects of Thermal Effluents from Wolseong Nuclear Power Plant on Macroalgal Composition and Community Structure (월성원자력발전소 온배수가 해조류 종조성 및 군집구조에 미치는 영향)

  • Choi, Han-Gil
    • ALGAE
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    • v.23 no.2
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    • pp.151-162
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    • 2008
  • Marine algal flora and community structure were seasonally examined at three sites in the vicinity of the Wolseong nuclear power plant in Korea from February to November 2006. A total of 126 seaweeds including 25 green, 31 brown, 70 red algae, and 1 marine plant were identified. The greatest number of species occurred at Jeonchonri (101 species) followed by intake (88 species) and discharge (29 species) during the study period. Of 126 seaweeds, 76 annuals and 13 warm tolerance species were recorded. Dominant species based on important value (IV > 10) were Ulva pertusa and Enteromorpha linza at intake, U. pertusa and Padina arborescens at discharge, and Sargassum horneri and Corallina pilulifera at Jeonchonri shore. Annual average biomass exhibited a wide range of variations, from 40.67g m-2 in dry weight at discharge to 133.69g m-2 at Jeonchonri. Among six functional groups, dominant group was coarsely-branched form at intake and Jeonchonri, but it was different at discharge site as filamentous form. Seaweed community structures of discharge site were distinguishable in decreasing species richness, biomass, species diversity index (H’), richness index (R), and evenness index (J’). Also, the ratios of green algae, warm tolerance species, annual algae, filamentous form and dominance index (DI) remarkably increased. Such phenomenons of discharge site are usually found under environmentally stressful conditions such as high disturbance. Thus, I can conclude that the heated effluents of nuclear power plant act as environmental stress influencing seaweed community structures and it can be detected with various community indices.

Species Compositon and Seasonal Variations of Fishes Collected by Winged Stow Nets on Anchors off Namhae Island (남해도 연안해역에서 낭장망에 의해 어획되는 어류의 종조성 및 계절변동)

  • Heo, Seong-Hoe;Gwak, Seok-Nam
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.34 no.3
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    • pp.309-319
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    • 1998
  • Species composition and seasonal variations of fishes collected by winged stow net on anchors in the coastal water off Namhae Island was studied from May 1989 m April 1990. During the study period, a total of 56 fish species were collected. Engraulis japonicus, Conger myriaster, Trichiurus lepturus, Sardinella zunasi, Ammodytes personatus, and Thryssa kammalensis predominated. These six species accounted for 93.9% of the total number and 81.3% of the total biomass of fishes collected. Fishes collected by winged stow nets on anchors were primarily small fish species or early juveniles of large fish species. Both abundance and species composition of fishes changed with season. Seasonal peaks of number of species occurred in spring and fall, while those of number of individuals and biomass occurred in spring. The lowest number of individuals and biomass were observed in winter. Low species diversity indices were observed in summer. These low diversity indices in summer were mainly due to predominance of E. japonicus which accounted for approximately 90% of all fishes collected. More species and greater biomass were collected during nighttime.

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Floristics of Halophytes and Hydrophytes in the Jungseonpo, Gwingok, and Gwangyangseo Rivers (중선포천, 관곡천, 광양서천에서 염생식물과 수생식물상 분포)

  • Huh, Man Kyu
    • Journal of Life Science
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    • v.30 no.2
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    • pp.186-190
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    • 2020
  • Halophytes are physiologically adapted to withstand the high salinity of water and saline soil. This study was conducted to elucidate the distribution of halophytes and hydrophytes in the Jungseonpo River (Sacheon-ci, Gyeongsangnam-do), Gwingok River (Hadong-gun, Gyeongsangnam-do), and Gwangyangseo River (Gwangyang-ci, Jeollanam-do) in Korea. A total of six species of halophytes and ten species of hydrophytes were collected in the Jungseonpo River. Halophytes in the Gwingok River and Gwangyangseo River numbered five species and 11 species, respectively. Hydrophytes in the Gwingok River and the Gwangyangseo River numbered 13 species in five families and 16 species in eight families, respectively. Of these, Phacelurus latifolius, endemic to the west and south coast of Korea, is an endangered species in the context of investigating the ecology and conservation of halophyte species. Many individual halophyte species have been diminished due to reduced habitable area caused by sand dune destruction. The rivers in the three areas on the south coast were also different in terms of distribution of salt plants due to regional differences, and they were all different from the well-developed west coast. Seven species, including Rosa wichuraiana, have been added to South coasts compared to past records.

Altitudinal diversity and distribution of butterflies inhabiting Mt. Jirisan, South Korea (지리산 나비의 고도에 따른 다양성과 서식 분포)

  • Lee, Sanghun;Ahn, Nahyun;An, Jeong-Seop
    • Korean Journal of Environmental Biology
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    • v.38 no.4
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    • pp.497-506
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    • 2020
  • This study surveyed the altitudinal diversity and distribution of butterflies inhabiting Mt. Jirisan. Field surveys were conducted thrice (May, June, and July) using a line transect method along four routes in 2015. During the survey, a total of five families, 58 species, and 769 individuals were collected. Of the species collected, the majority belonged to the family Nymphalidae (28 species), followed by Hesperiidae (nine species), Pieridae (eight species), Lycaenidae (seven species), and Papilionidae (six species). As for the individuals, Pieridae accounted for the largest number (333 individuals), followed by Nymphalidae (309 individuals), Lycaenidae (63 individuals), Hesperiidae (33 individuals), and Papilionidae (31 individuals). A cluster analysis performed on the butterfly species distinguished three altitude zones. The butterflies showed different ecological traits in each of the altitude zones. Analysis of the altitudes of the habitats of eight dominant species revealed that each species inhabited a particular altitude. This study confirmed the hypothesis that continuous monitoring will identify changes in the altitudinal distribution and diversity of butterflies on Mt. Jirisan in response to climate change.

Post-release Monitoring after Reintroduction of Captive-reared Korean Endangered Frog, Pelophylax Chosenicus

  • Park, Chang-Deuk;Kwon, Kwanik;Yoo, Nakyung;Lee, Jung-Hyun;Kang, Dong-Won;Park, Jong-Sung;Yoo, Jeongwoo;Kim, Keun-Sik;Yoon, Ju-Duk
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • v.2 no.2
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    • pp.114-119
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    • 2021
  • To restore the Gold-spotted pond frog (Pelophylax chosenicus), a Korean endangered frog, 600 captive-reared individuals were reintroduced between August and September 2019 into an aquatic garden in the National Institute of Ecology where P. chosenicus had previously inhabited. After reintroduction, six post-release monitoring sessions were conducted from August 2019 to May 2020. Monitoring was performed using three methods (counting calls, observation, and capture) from sunset to midnight near release sites, eliminating potential threat factors. Snout-vent lengths and body weights of recaptured individuals were measured before they were released immediately. We noted that both snout-vent lengths and body weights of recaptured individuals were slightly higher than those before. The average recapture rate was 4.66%. Reintroduced frogs were recaptured at the last monitoring session conducted in May 2020, indicating that these reintroduced frogs hibernated during the winter successfully. We found that these reintroduced frogs successfully settled after release. This result will be useful for establishing management strategies for endangered frogs in Korea. Particularly, post-release monitoring could be an essential approach in the restoration program of a target species.

Analysis of the Correlation Between Ecological Status and Location Environment by Cultivated Land Restoration Type of Geumgang Riverine Ecobelt

  • Lee, Soo-Dong;Back, Seung-Jun;Kang, Hyun-Kyung
    • Journal of People, Plants, and Environment
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    • v.24 no.4
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    • pp.389-401
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    • 2021
  • Background and objective: The purpose of this study is to investigate the ecological status of six areas around Geumgang River that used to be farmlands before they were restored as a riverine ecobelt. This study aims to analyze the correlation between the location environment and ecological status of the sites to identify the environmental factors affecting them. Methods: The sites are classified into four types according to restoration: terraced paddy fields, flat paddy fields, artificial wetland, and landscape forest. The survey items were divided into land use status, plant ecology, and animal ecology. Results: In terms of plant ecology, terraced paddy fields showed favorable naturality with the rate of native species above 90% and the naturalization index below 10%. In terms of animal ecology, the total number of species found in these areas was biggest in terraced paddy fields, followed by flat paddy fields, artificial wetland, and landscape forest. Regarding species diversity, terraced paddy fields also showed abundant species with an average of 1.05 to 1.09. The results of the correlation analysis showed that the forest area around the sites had the most significant effect on species diversity. The grassland and open water area showed a positive correlation with the total number of animal species and the number of dragonflies, confirming that the marshy grassland had a positive effect. As the cultivated land and urbanized area around the sites increased, it had a negative effect on the distribution of native species and the number of animal species that appeared, and a positive effect on the naturalization index. Conclusion: It is necessary to establish preemption and restoration plans for sites such as grasslands adjacent to the forest and terraced paddy fields in order to promote resilience of the diverse species returning to the purchased lands.

A study on species composition and bycatch status of fishes by a three-side fyke net fisheries in Asanho Lake and Chungjuho Lake (아산호와 충주호의 삼각망에 의한 어획물 종 조성과 혼획 실태 연구)

  • Min Ah HEO;Heui Chen AN;Wan Ok LEE;Yong Beam PYEON;Seong Hun KIM
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.59 no.3
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    • pp.196-205
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    • 2023
  • This study investigated the species composition and bycatch status of fishes by fyke net between June and November 2020 in Asanho lake and Chungjuho lake. During the survey period, the catches in Asanho lake were identified as 2,931 individuals of 16 species from a total of six families and in Chungjuho lake were identified as 1,645 individuals of 14 species from a total of eight families. The dominant species in Asanho lake was Erythroculter erythropterus which accounted for 59.6% of the the total number of individuals and 40.5% of the total biomass caught. The dominant species in Chungjuho lake was Lepomis macrochirus which accounted for 48.2% of the the total number of individuals and Erythroculter erythropterus which accounted for 60.2% of the total biomass caught. The bycatch rates of non-commercial species in Asanho lake and Chungjuho lake were 77.0% and 82.6%, respectively. As a result of analyzing the frequency distribution of the total length of Carassius auratus and Siniperca scherzeri, which were the dominant species among commercial species, the bycatch rate of small individuals was 87.1%, and 42.7%, respectively.

Bycatch reduction plan of offshore dredge in the western sea, Korea (서해안 근해형망 어업의 혼획저감 방안)

  • Sug-Tai KIM;Hyun-Young KIM
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.59 no.4
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    • pp.290-300
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    • 2023
  • This study aimed to identify the actual catch situation of offshore dredge gear which is newly regulated in the legislation. It's also conducted to identify the species composition, weight of the catch including the target species and incidental catches, and to provide the basic information necessary for the resource management of aquatic organisms caught by offshore dredge. During the investigation period (from September 2022 to May 2023), a total of 61 species appeared in the test operation sea of Boryeong, Chungcheongnam-do and Gunsan, Jeollabuk-do, with 31 species of fishes, 11 species of malacostraca, six species of gastropoda, five species of bivalvia, three species of cephalopoda, three species of asteroidea, one species each of asteroidea and holothuroidea appeared. According to the results of the test operation conducted in September and November 2022, the non-catch season of Atrina (Servatrina) pectinata, 1,203 shellfishes were caught out of 2,979 caught in number, showing a bycatch rate of 59.6%, and by weight, 157.9 kg of shellfish was caught out of the total catch of 448.4 kg, showing a bycatch rate of 64.8%. On the other hand, in February and May 2023, the catch season for Atrina (Servatrina) pectinata, 3,692 fishsells were caught out of the 4,232 catches in total, showing a bycatch rate of 12.8%, and by weight, 1,185.0 kg of shellfish was caught out of the total catch of 1,293.2 kg, showing an 8.3% bycatch rate.