• Title/Summary/Keyword: Oryuk islets

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Monthly Variations of Cirriped Larvae near Oryuk Islets off Busan, Korea (부산 인근 오륙도 주변에 출현하는 만각류 유생의 월별 출현 양상 변화)

  • Choi, Jungwha;Kang, Junghun;Park, Wongyu
    • Korean Journal of Environmental Biology
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    • v.33 no.2
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    • pp.230-239
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    • 2015
  • Monthly variations of cirriped larvae near Oryuk islets off Busan were investigated at four stations from January 2012 to January 2013. Zooplankton was vertically collected, using NORPAC net (mouth 45 cm, mesh $200{\mu}m$), from the surface to 1 m above the bottom. 12 species belong to five genera of 4 families were identified including one unidentified species. Cirriped larvae occupied small portion of total zooplankton, ranging 0.02 to 4.1% of total zooplankton densities. The densities varied monthly from $1inds.m^{-3}$ to $715.1inds.m^{-3}$, which was highest in September and lowest in February. Chthamalus challengeri, Balanus glanula, B. improbisus, B. nubilus and Octomeris sulcata were dominant species and accounted for 70.1% of total cirriped larvae. Larval densities of cirripeds between stations were not significantly different (F=0.237, p=0.870). The larval communities were grouped into two groups by cluster analysis. We discussed the distribution patterns of cirriped larvae in relation to oceanographic characteristics in the study area.

Variation of Community Structure of Decapods by Season and Depth near Oryuk Islets off Busan, Korea (오륙도 주변해역 십각류의 계절별 수심별 종조성과 군집구조)

  • PARK, Hyun-Jung;PARK, Won-Gyu;CHOI, Jung-Wha;LEE, Bo-Ram
    • Journal of Fisheries and Marine Sciences Education
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    • v.29 no.1
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    • pp.257-269
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    • 2017
  • The occurrence variations of decapods by season and depth off Oryuk Islets, Busan were investigated at seven stations in April and October 2009, July 2010 and January 2011. Decapods were collected by SCUBA diving at 5 m and 10 m depths. 46 species belonging to 18 families in 3 orders were identified. Pilumnus minutus, Pugettia intermedia, Pachycheles stevensii, and Paguristes japonicus were dominant species, comprising 73.0% of total decapods. P. minutus and P. intermedia were abundant in all seasons (except summer) while P. stevensii and P. japonicus were abundant in fall and summer. Dominant species were divided into three groups (resident species, seasonal species and temporary species) on the basis of their occurrence patterns. P. minutus and P. intermedia were resident species while P. stevensii, P. japonicus were temporary species. The species number, density and biomass of decapods were fluctuated by seasons. They were highest in fall and lowest in winter. This study implied that the variations of species number and density of decapods were significantly related with seasonal change of water temperature.