• Title/Summary/Keyword: Seasonal abundance

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A Study on Meiofauna Community in the Subtidal Sediment outside of the Saemangeum Seadike in the West Coast of Korea (새만금 외해역 조하대 퇴적물에 서식하는 중형저서동물 군집에 관한 연구)

  • Kim, Kwang-Soo;Lee, Seunghan;Hong, Jung-Ho;Lee, Wonchoel;Park, Eun-Ok
    • Ocean and Polar Research
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    • v.36 no.3
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    • pp.209-223
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    • 2014
  • The community structure of benthic meiofauna was investigated from seasonal surveys at seventeen stations off the Saemangeum area, in 2007. Ten meiofaunal taxa were identified. Nematodes were the dominant faunal group in all seasons and harpacticoids were dominant only at a few stations. The mean density of meiofauna was 383 indiv. $10cm^{-2}$, highest in May and November (434 indiv. $10cm^{-2}$), lowest in February (284 indiv. $10cm^{-2}$). Meiofaunal mean biomass was $80.49{\mu}gC{\cdot}10cm^{-2}$, highest in November ($99.54{\mu}gC{\cdot}10cm^{-2}$), lowest in February ($51.56{\mu}gC{\cdot}10cm^{-2}$). Cluster analysis revealed that the study area was composed of three benthic meiofaunal communities. There were significant correlations between major meiofaunal groups and sediment composition and the concentrations of heavy metals. The abundance of harpacticoids are positively correlated with silt (0.559, p < 0.01) and clay (0.340, p < 0.01), and negatively correlated with sand (-0.548, p < 0.01). Harpacticoids also showed positive correlations with heavy metals. The community structure of meiofauna in the study area varied seasonally in response to the change of sediment composition.

Changes in Species Composition of Fishes in the Nakdong River Estuary (낙동강 하구역 어류의 종조성 변화)

  • KWAK Seok Nam;HUH Sung-Hoi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.2
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    • pp.129-135
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    • 2003
  • Species composition and seasonal variations in abundance of fishes in the Nakdong River estuary were investigated using an otter trawl seasonally from September 2001 to July 2002. These data were compared with those obtained before the construction of the estuary barrage in 1987. A total of 3,648 fishes that comprised 30 species in 21 families were collected. Acanthogobius flavimanus and Leiognathus nuchalis predominated, and they were responsible for $71.2\%\;and\;67.8\%$ in the number of individuals and biomass, respectively. The next abundant fish species were Platycephalus indicus and Liparis tanakai. Compared with data obtained before the construction of the estuary barrage in 1987, abundances of Acanthogobius flavimanus, Platycephajus indicus, Liparis tanakai, Tridentiger trigonocephalus and Lateolabrax japonicus increased, while those of Pholis fangi, Repomucenus valenciennei, Sardineila zunasi and Scomber japonicus decreased. These results seems to be related to change of sediment environment caused by irregular discharge of freshwater with variation of sea water movement in the Nakdong River estuary.

Finless porpoise, Neophocaena phocaenoides, Distribution in the South Sea of Korea (남해안 상괭이(Finless porpoise)의 분포)

  • Choi, Seok-Gwan;Park, Kyum-Joon;Kim, Hyun-Woo;Lee, Young-Ran;Park, Ji-Eun;Moon, Dae-Yeon;An, Yong-Rock
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.6
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    • pp.665-669
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    • 2010
  • To confirm the distributon of finless porpoise, Neophocaena phocaenoides, in the South Sea of Korea, data on bycatch, stranding, and drifting of finless porpoises from 1999 to 2009 were used and a sighting survey was conducted from the R/V Tamgu No. 9 and 10 in June and November, 2009 and March, 2010. The total number of bycaught, stranded, and drifting finless porpoises was 607, with position being known for 186 of these. At the center of Yeosu, there were few position data on bycaught, stranded, and drifting finless porpoises, and data could not confirm the distribution of finless porpoises. Thus, there were limits on the usefulness of bycaught, stranded, and drifting data for confirming the distribution of finless porpoises. In the three sighting surveys, the sighting rate was highest at 0.231 ind./n.m. in the western South Sea in June, 2009. Sighting rate was less than 0.1 ind./n.m. in November, 2009 and March, 2010. This is likely to be due to seasonal migration in western South Sea. All sighting rates in the eastern South Sea were over 0.13 ind./n.m.. According to the results of the sighting survey, finless porpoises are distributed around the islands and inner bay along the path of the research vessel in the South Sea. There were numerous finless porpoises in the offshore areas of Mokpo, Yeosu, Tongyeong, Dadaepo, and Gaduk-do. This study will be utilized as part of a future abundance assessment of finless porpoise in the South Sea of Korea.

Seasonal and Annual Variations of Catch by Large Purse Seine off Korea (한국 근해 대형선망 어획물의 계절 및 연 변동 분석)

  • Baik, Chul-In;Park, Jong-Hwa;Choi, Kwang-Ho;Hwang, Sun-Do
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.6 no.3
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    • pp.164-179
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    • 2001
  • Spatio-temporal variation in species composition, abundance and distribution of fisheries resources caught by large purse seine off Korea from 1991 to 1994 was analysed. Out of 19 species, Scomber japonicus (54.7%), Sardinops melanostictus (20.4%), Trachurus japonicus (9.1%), and Scomberomorus niphonius (6.2%) were predominated in catch. These 4 pelagic fishes occupied 90% of total catch. Major pelagic fishes caught by large purse seine were dispersed to northward from spring to summer, and migrated to the southern wintering ground during winter. Fishing effort (number of haul) was high in summer, but catch per unit effort showed a peak in winter. The high CPUE in winter seemed to be related to aggregation of the pelagic fish to the wintering ground in the southern sea. After spawning, they were widely dispersed for feeding in warm months.

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Distribution of Southern Earthworm Race in Mulberry Tree Cultivation Area (뽕나무 경작지의 남방계지렁이 분포)

  • Hong, Yong
    • Korean Journal of Environmental Biology
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    • v.32 no.3
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    • pp.263-269
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    • 2014
  • In this study, I investigated the species composition in the Mulberry tree cultivation area from April 2013 to March 2014 at Busan. Five genera and nine species found are as follows: Aporrectodea caliginosa (Savigny, 1826), Bimastos parvus (Eisen, 1874), Eisenia fetida (Savigny, 1826), Drawida japonica (Michaelsen, 1892), Amynthas heteropodus (Goto&Hatai, 1898), Amynthas agrestis (Goto & Hatai, 1899), Amynthas corticis (Kinberg, 1867), Amynthas hilgendorfi (Michaelsen, 1895), and Amynthas sp. A total of 317 individuals of Aporrectodea caliginosa (Savigny, 1826) was collected. Ap. caligionosa and A. heteropodus were found to be the most dominant species during the study period. Interestingly, the maximum population density of Ap. caligionosa was recorded to be in the month of October. Further details analysis indicated that, its population increased rapidly during the breeding season between summer and autumn and thereafter gradually decreased through winter toward the following February. Three growth stages of Ap. caligionosa occurred almost simultaneously with abundance composition of 76% in aclitellum, 12.6% in semiclitellum, and 11.4% in clitellum. Based on my study results, I suggest that this data could be useful for the scientific community to analyze the distribution of southern earthworm species in mulberry tree cultivation area.

Fishing investigation and species composition of the catch caught by a bottom trawl in the Yeo-ja bay, Korea (여자만 저층트롤 어획실태와 종조성)

  • Kim, Joo-Il;Seo, Young-Il;Lee, Sun-Kil;Kim, Sung-Tae;Joo, Hyun;Jang, Sun-Ik;Oh, Taeg-Yun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.43 no.4
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    • pp.241-250
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    • 2007
  • Fishes were caught by a bottom trawl in the Yeo-ja bay of Korea by every three month(March, June, September and December) and seasonal variation of abundance and species composition were studied in 2005. The catches were 1,187kg and were composed of 115 species with 20 hauls by 5 stations. The dominant species caught were Charybdis bimcaulata, Crangon hakodatei, Parapenaeus fissurus, Oratosguilla oratoria, and Thryssa purava. One hundred fifty species were identified as fish(38%), crustacea(20%), mollusca(4%) and others(38%) which including of Asterias amurensis. The amount of species was high in June and September and low in March and December. The diversity index(H') was about 1.2-2.5 and station similarity of fishes caught among the community was 0.009-0.230.

Studies on ecolgy and control for the purplish stem borer (Sesamia inferens Walker) in Korea (한국에서의 벼밤나방(Sesamia inferens Walker)의 생태와 약제방제에 관한 연구)

  • Bae S. H.;Lee J. O.;Lee B. H.
    • Korean journal of applied entomology
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    • v.7
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    • pp.27-32
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    • 1969
  • The purplish stem borer (Sesamia inferens Walker). which was infested in southern part of Korea. attack rice plant. and its damage appear quite serious in some districts. This study was conducted to investigate the life history. seasonal abundance and control of the insect pest. The pest overwinter as larvae and it seems to have 2-3 generations in a year. It takes 56.6 days in the shortest one while the longest one takes 74.6 days. Three peaks of moth appearance are May-June. end of July and end of August, respectively. The effectivencess of insecticides was compared with EPNec $45\%$ and the different granular insecticides in pot experiment. In the result. M. Parathion G. EPNec, Diazinon G and Lebaycid G showed good control of the pest. with the infestation of $12.0,\; 22.9\%,\; 24.7\%,\; and\; 27.3\%$ respectively, while the untreated has $62.6\%$

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Structure and Seasonal Patterns of Ground Beetles Community in Wangpi-Cheon Watershed, South Korea

  • Park, Jinyoung;Jung, Jong Kook;Cha, Jin Yeol;Choi, Jong Bong;Park, Jong Kyun
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • v.1 no.1
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    • pp.41-51
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    • 2020
  • Ground beetle fauna of Wangpi-cheon watershed in Yeongyang-gun to Uljin-gun, Gyeongsangbuk-do was investigated from May to October in 2012. Ground beetles were collected by pitfall trapping. A total of 38 species of 20 genera belonging to 8 subfamilies were identified from 2,486 collected ground beetles. Species richness was high in Pterostichinae (16 species), Carabinae (8 species), Harpalinae (5 species), Callistinae (3 species), Nebriinae (3 species) and others (1 species). Dominant species were Synuchus cycloderus (1,025 individuals) and Aulonocarabus seishinensis seishinensis (332 individuals), Pristosia vigil (133 individuals), and Coptolabrus smaragdinus branickii (117 individuals) in order. Monthly changes in abundance of upper dominante genera Pterostichus, Aulonocarabus, Coptolabrus species and Synuchus, Pristosia, Colpodes species showed that the former had the highest number in August whereas the latter increased in June and September. The genus Pterostichus species were preferred in deciduous forest in Wangpi-cheon watershed, while the genus Synuchus species were collected in mixes forest adjacent to farmland and recreation facilities and the genera Chlaenius, Harpalus species were collected in mixes forest adjacent to farmland nearby stream. Non-metric multidimensional scaling (NMDS), ground beetles and sites could be divided into two distinct groups: St. 1, St. 2, St. 3 group and St. 4 group. Some species such as Pterostichus orientalis orientalis, P. vicinus and P. bellatrix were particularly abundant at St. 4.

Thermal Discharge Effects on the Species Composition and Community Structure of Macrobenthos in Rocky Intertidal Zone Around the Taean Thermoelectric Power Plant, Korea (태안화력발전소 주변 암반조간대에 서식하는 대형저서동물의 종조성 및 군집구조에 미치는 온배수의 영향)

  • Jung, Yun-Hwan;Kim, Hyung June;Park, Heung-Sik
    • Ocean and Polar Research
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    • v.40 no.2
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    • pp.59-67
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    • 2018
  • This study was conducted to understand the distribution and changes of macrobenthos on rocky intertidal areas around Taean thermoelectric power plant, Also, the purpose of this study was to produce a base-line data on the changes in water temperature due to the operation of the power plant and to understand its thermal impact on the macrobenthic community on intertidal rocky bottoms. A field survey was seasonally conducted at 3 rocky intertidal sites around the Taean thermal power plant. There was no seasonal difference in the community parameters such as number of species, mean density, biomass and species diversity during the study period. The major dominant species were Chthamalus challenger, Littorina brevicula, Crassostrea gigas. In comparison with previous study, thermal discharge in the study area did not significantly affect the distribution of dominant species. The structure of the macrobenthic community revealed that there were showed 3 different faunal groups depending on the difference in the mean density of major dominant species. The result of SIMPER analyses to determine which species were the main contributors to the differences between each community, C. challenger, Lottia spp. And Mytilus galloprovincialis, etc., revealed that there was showed a significant difference between each group. The abundance of M. galloprovincialis, showed a significant difference between faunal groups.

Seasonal variation and species composition of fishes communities in artificial reef unit at marine ranching area in the coastal waters off Jeju island, Korea (제주바다목장 해역 내 인공 어초군에 서식하는 어류군집의 종조성 및 계절변동)

  • Oh, Taeg-Yun;Cha, Hyung-Kee;Chang, Dae-Soo;Hwang, Choul-Hee;Nam, Yun-Ju;Kwak, Seok-Nam;Son, Min-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.2
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    • pp.139-147
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    • 2010
  • This study monitored a variety of marine fish communities in artificial reefs unit of the total 5 types (Dice type, Octagonal turtle type, Two-stage tube type, Gazebo type, Tetrapod type) which are located in the marine ranching at Jeju island by scuba diving in May, July, October and December 2009. Underwater photographing was accomplished at total 3 phases (condition of artificial reefs photographing, concentric circle movement photographing and line transect photographing). The preservation condition of artificial reefs facility was very good, and the dominant species were Chromis notatus, Sebastes thompsoni, Oplegnathus fasciatus and Halichoeres poecilopterus. Fish abundance was high in May and June, and low in October and December, 2009. Chromis notatus was dominant at the all types of artificial reefs, Halichoeres poecilopterus for Gazebo type and Tetrapod type of artificial reefs, and Sebastes thompsoni for Dice type, Octagonal turtle type and Two-stage tube type of artificial reefs.