• Title/Summary/Keyword: eelgrass bed

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Variation in abundance and species composition of fishes in eelgrass (Zostera marina) bed and around Geomundo (거문도 연안 잘피밭과 주변해역의 어류 종조성 및 양적변동)

  • SIN, Kyung-Soo;HAN, Kyung-Ho;BAEK, Jeong-Ik;LEE, Sung-Hoon;LEE, Won-Kyo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.4
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    • pp.484-492
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    • 2015
  • The purpose of this study is to compare the ichthyofauna between the eelgrass bed waters located in the open sea and the nearby sea free of eelgrass, and this study collected a total of 26 species. Comparing the fish collected on the eelgrass bed (St.2) of Geomun-do coast with the fish collected on the coastal waters (St.1) void of the nearby eelgrass bed, the fish collected from the eelgrass bed included 19 species, 413 individual with 16,110.6g in weight while the fish collected from the coastal waters void of the eelgrass bed included 19 species, 290 individuals with 12,961.5g in weight. Accordingly, it was found that the population size and biomass of the fish collected from the eelgrass bed were higher than the coastal waters void of the eelgrass. This study could identify that diversity, richness, evenness index except dominance were also much higher even in the result of cluster analysis.

Growth and Estimated Production of Acanthogobius flavimanus in an Eelgrass (Zostera marina) Bed and Unvegetated Tidal Flat of Dongdae Bay

  • Kwak, Seok-Nam;Huh, Sung-Hoi;Kim, Ha-Won
    • Animal cells and systems
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    • v.13 no.3
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    • pp.315-321
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    • 2009
  • The growth and estimated production of Acanthogobius flavimanus (1.9${\sim}$24.7 cm TL) were investigated in an eelgrass bed and unvegetated tidal flat of Dongdae Bay, Korea from March 2006 to February 2007. Growth in fish total length was expressed by the von Bertalanffy's growth equation as: $L_t=43.238(1-e^{-03138(t+02507)})$. Estimated densities, biomass, daily and annual production, and P/B ratio were higher at eelgrass bed than those of at unvegetated tidal flat. Monthly variation in daily production was large; the peak numbers occurred in November 2006 ($0.0014g/m^2$/day) at eelgrass bed, whereas was $0.002g/m^2$/day in July 2006 at unvegetated tidal flat. The eelgrass bed has been supported to maintain capacity of higher production of A. flavimanus than those of in unvegetated tidal flat.

Seasonal Variation in the Biomass of Eelgrass (Zostera marina) and Epiphytic Algae in Two Eelgrass Beds around Namhae Island in Korea

  • Kwak, Seok-Nam;Huh, Sung-Hoi
    • Fisheries and Aquatic Sciences
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    • v.12 no.3
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    • pp.219-226
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    • 2009
  • Seasonal variation in the biomass of eelgrass (Zostera marina) and epiphytic algae in two eelgrass beds (Dongdae and Aenggang Bay) around Namhae Island was investigated throughout 2005. Shoot density and eelgrass biomass differed across months and locations. Peak shoot density occurred from April to August 2005, whereas eelgrass biomass was higher in July and August 2005. Shoot density as well as eelgrass biomass were higher in Dongdae Bay compared to Aenggang Bay. A total of 21 epiphytic algal species (4 Chlorophyta, 2 Phaeophyta, and 15 Rhodophyta) were collected, and dominant species included Polysiphonia japonica, Lomentaria hakodantensis, Symphyocladia latiuscula, Champia sp., and Heterosiphonia japonica. Seasonal variation in both the species composition and biomass of epiphytic algae was substantial: peak epiphytic algal biomass occurred in January and December 2005. We also observed high epiphytic algal biomass in the eelgrass bed of Dongdae Bay. Seasonal changes in the biomass of eelgrass and epiphytic algae were primarily influenced by water temperature, whereas those of the epiphytic algal community were also correlated with eelgrass (substrate) morphology and growth, the life cycle of epiphytic algae, and physical characteristics within eelgrass beds. The spatial variation of eelgrass density and biomass were also limited by sediment characteristics.

Creating Eelgrass Beds Using Granulated Coal Ash (석탄회 조립물을 이용한 잘피군락 조성에 관한 연구)

  • Kim, Kyunghoi;Hyeon, Yejin;Hibino, Tadashi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.7
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    • pp.814-820
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    • 2016
  • In order to utilize coal ash for eelgrass beds, a pilot plant experiment was carried out. Eelgrass was transplanted to on artificial bed made of granulated coal ash. Successful settlement of eelgrass was achieved and the density of the eelgrass increased at an exponential rate through vagetative propagation after 24 months. An increase in biodiversity in and around the artificial eelgrass bed was observed after the transplant took place. From the results of this experiment, it can be concluded that granulated coal ash is a suitable material for creating eelgrass beds.

Feeding Habits of Lateolabrax Japonicus in the Eelgrass ( Zostera Marina ) Bed in Kwangyang Bay (광양만 장피밭에 서식하는 농어 ( Lateolabrax Japonicus ) 의 식성)

  • Heo, Seong-Hoe;Gwak, Seok-Nam
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.34 no.2
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    • pp.191-199
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    • 1998
  • Feeding habits of Lateolabrax Japonicus collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. L. Japonicus was a carnivore which consumed mainly amphipods (gammarid amphipods and caprellid amphipods), crabs, caridean shrimps and copepods. Its diets included small quantities of fishes, mysids, polychaetes, tanaids and isopods. Three distinct ontogenetic feeding groups were noted : (1) 1~2 cm SL individuals preyed heavily on copepods. (2) 2~15 cm SL individuals preyed heavily on amphipods. (3) individuals over 15 cm SL preyed heavily on crabs, caridean shrimps and fishes. L. Japonicus showed seasonal changes in prey composition. These changes were not caused by seasonal changes in food availability, but by changes in the size composition of L. Japonicus occurred in the eelgrass bed.

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Species Composition of Fish Assemblage in a Small Scale Eelgrass Bed of Tongyeong, Korea (경남 통영의 소규모 잘피밭 어류군집에 관한 연구)

  • Kim, Jun-Sop;Gwak, Woo-Seok
    • Korean Journal of Ichthyology
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    • v.24 no.3
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    • pp.191-200
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    • 2012
  • Fish species composition in eelgrass bed of Punghwa-ri in Tongyeong, Korea was determined using monthly samples collected by a surf net from November 2010 to October 2011. During the study period, a total of 30 species, 5,511 individuals and 6,933.4 g of fishes were collected. The dominant fish species were Pholis nebulosa, Syngnathus schlegeli, Rudarius ercodes, Pseudoblennius cottoides, Sebastes inermis, and Aulichthys japonicus which accounted for 93.4% of total number of individuals collected. Most fishes collected in the eelgrass bed belong mainly to small fish species or juveniles of large fish species. Eelgrass shoot density reached a peak in April 2011, and then decreased to a minimum in January 2011. The seasonal variation of fish assemblage in an eelgrass bed of Punghwa-ri was correlated to the variations in the water temperature, eelgrass density and biomass, and abundances of major prey organisms.

Comparisons of Fish Assemblages Associated with Eelgrass Bed and Adjacent Unvegetad Habitat in Jindong Bay (진동만 잘피발과 인근 잘피가 없는 해역의 어류군집 비교)

  • Kwak, Seok Nam;Huh, Sung-Hoi;Choi, Chang Geun
    • Korean Journal of Ichthyology
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    • v.18 no.2
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    • pp.119-128
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    • 2006
  • Fish assemblages associated with eelgrass beds and unvegetated area were compared based on specimens collected every month in Jindong Bay. The common fish species were Hexagrammos otakii, Acanthopagrus schlegeli, Lateolabrax japonicus, Pholis nebulosa, P. fangi, Leiognathus nuchalis, Repomucenus valenciennei, and Acanthogobius flavimanus. H. otakii, A. schlegeli, P. nebulosa and L. japonicus were higher abundance in an eelgrass bed than unvegetated area, whereas P. fangi, R. valenciennei and A. flavimanus were higher in unvegetated area. Sillago japonicus, Hippocampus japonica, Takifugu niphobles, Pseudoblennius percoides, Sebastes inermis, Syngnathus schlegeli, Sebastes schlegeli were found in an eelgrass bed, but not in unvegetated area. Most of fish species were primarily small fish species or juveniles of fish species in an eelgrass bed, while larger fish species were found in unvegetated area. The eelgrass bed in Jindong Bay seem to play a nursery role for fishes. Seasonal variations in both species composition and abundance were large in two habitats; higher number of species and individuals occurred May 2002, and April 2002 to July 2002, while biomass was the highest in April 2002 and July 2002. Fish numbers as well as biomass were lowest in January 2002. Species richness, number of individuals and biomass of fishes in an eelgrass bed were significantly higher than those of in unvegetated area. These result suggest that differences in fish species richness and abundances are primarily related to habitat structure. Different habitat preferences were evidenced for the juveniles and adult of several fish species.

Seasonal Variations in Species Composition and Abundance of Fish and Decapods in an Eelgrass (Zostera marina) Bed of Jindong Bay

  • Kwak, Seok-Nam;Park, Joo-Myun;Huh, Sung-Hoi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.3
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    • pp.259-269
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    • 2014
  • The objectives of this study to determine seasonal changes in species composition and abundance of fish and decapod assemblage, and the relationships between environmental factors and their abundance in an eelgrass bed of Jindong Bay. A total of 26 fish species and 29 decapod species were collected by a small beam trawl from an eelgrass bed in Jindong Bay in 2002. The dominant fish species were Hexagrammos otakii, Pholis neulosa and P. fangi and these accounted for 48.4 % in the total number of individuals. Dominant decapod taxa were Palaemon macrodactylus, Charybdis japonica, Pagurus minutus and C. bimaculata. These were primarily small species or early juveniles of larger species. Species composition and abundance varied greatly showing a peak in the number of individuals in April and May, and peak biomass in fish in July and decapods in August. Catch rate was low in winter months both in fish and in decapod. Seasonal changes in the abundance of fishes and decapods corresponded with eelgrass biomass and abundance of food organisms indirectly.

Seasonal Variation in Fish Species Composition in the Coastal Water of Samdong-myeon, Namhae, Korea (남해군 삼동면 연안 어류의 월별 종조성 변화)

  • Kim, Jun Sop;Lee, Yong-Deuk;Lee, Seung Hwan;Park, Jun Su;Gwak, Woo-Seok
    • Korean Journal of Ichthyology
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    • v.30 no.1
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    • pp.55-64
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    • 2018
  • Fish assemblages in a sandy shore and an eelgrass bed were compared based on monthly samples in the southern coastal water of Korea. Samples were collected by a beam trawl in the sandy shore and a surf net in the eelgrass from March to February 2012. The common fish species were Syngnathus schlegeli, Pseudoblennius cottoides, Pholis nebulosa, Favonigobius gymnauchen, Gymnogobius heptacanthus, Pseudopleuronectes yokohamae, Takifugu niphobles. Among them S. schlegeli, Urocampus nanus, P. cottoides, P. nebulosa, T. niphobles were high abundance in the eelgrass bed than in the sandy shore, whereas Acanthogobius flavimanus, Acentrogobius pflaumi, F. gymnauchen, G. heptacanthus, P. yokohamae were high in the sandy shore. Aulichthys japonicus, Hippocampus coronatus, Sebastes inermis, Lateolabrax japonicus, Siganus fuscescens were found in the eelgrass bed, and Thryssa hamiltoni, Mugil cephalus, Inimicus japonicus, Platycephalus indicus, Hexagrammos otakii, Furcina ishikawae, Liparis tanakae, Repomucenus curvicornis, and Eutaeniichthys gilli were observed in the sandy shore. Species composition and abundance varied seasonally in two habitats; The number of species and abundance was high in August and September, while biomass was the highest in April and September. Fish numbers as well as biomass were lowest in February. Number of individuals and biomass of fish in the eelgrass bed were significantly higher than those of in the sandy shore. Some fish preferred to live in the eelgrass were collected in the sandy shore, while fish preferred to live in the sandy shore were rarely collected in the eelgrass.

Feeding Habits of Juvenile Liparis tanakai in the Eelgrass, Zostera marina Bed in Kwangyang Bay (광양만 잘피밭에 서식하는 꼼치 (Liparis tanakai) 유어의 식성)

  • KWAK Seok Nam;HUH Sung-Hoi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.4
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    • pp.372-377
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    • 2003
  • Feeding habits of juvenile Liparis tanakai collected from the eelgrass bed in Kwangyang Bay were studied. L. tanakai (2.0-6.0 cm SL) was a carnivore which consumed mainly amphipods (caprellids and gammarids) and caridean shrimps. Its diets also included a large amount of copepods, polychaetes and small fishes. Three distinct ontogenetic feeding groups were noted: (1) the individuals of 2.0-2.5 cm SL preyed heavily on copepods, (2) individuals of 2.5-4.0 cm SL fed mainly on amphipods. (3) individuals over 4.0 cm SL preyed mainly on caridean shrimps and small fishes. The dietary breadth of each size class showed relatively low value, and this means that juvenile L. tanakai depends on only few kinds of food organisms.