• ALGAE
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• v.30 no.2
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• pp.139-146
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• 2015

Urchin barrens have been a major issue of rocky coastal ecosystems in temperate regions. In South Korea, the east coast and Jeju Island have especially been a focus because the area of barren ground increases in spite of continual efforts to install artificial reefs. This study approached the urchin barrens issue in South Korea, by focusing on a correlational analysis of urchin and macroalgal abundance. Urchin density and algal species coverage were obtained using a quadrat image analysis. Subtidal sites were then classified into three groups according to the average densities of urchins to evaluate the characterization of the macroalgal community: no urchin (NU) zone; transition (TR) zone, $4inds.\;m^{-2};$ and urchin (UR) zone, ${\geq}8inds.\;m^{-2}$. The average urchin density in the study site was $4.7inds.\;m^{-2}$ and 57 macroalgal species were found in the study site. From the NU zone to UR zone, total species number, species diversity index and evenness gradually decreased, whereas the dominance index increased. The algae species with negative correlations were Grateloupia divaricata, Polysiphonia morrowii, Chondracanthus intermedius, Delesseria violacea, Desmarestia viridis; and those with positive correlations were the crustose corallines, Sargassum horneri. Other species were not significantly correlated with urchin density. The significant correlations indicate that the abundance of some macroalgal species is proportionally regulated by sea urchin density. This study also shows how macroalgal vegetation changes in response to an urchin's density gradient in a natural condition; and there is a TR zone that existed with respect to an intermediate level of algal abundance.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.273-278
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• 2016

The seasonal variations in species composition and abundance of the fish assemblage were studied in the rocky subtidal habitat around the Jam-do, Jinhae. Fish samples were collected monthly from September 2007 to July 2008 using a pot. During study, a total of 48 fish species belonging to 24 families were collected. The dominant species were Sebastes longispinis, Pseudoblennius cottoides, Sebastes inermis, Rudarius ercodes, Ditrema temminckii, Ernogrammus hexagrammus, which accounted for 71.0% of the total number of individuals collected. The number of species, number of individuals, biomass and diversity greatly fluctuated showing a peak in the number of species, number of individuals and species diversity in autumn, whereas the biomass was the highest in spring. Abundance of dominant species varied with season. S. longispinis was abundant during spring and summer, while the abundance of P. cottoides was higher during autumn and spring. S. inermis occurred with high number in September, December and May, whereas R. ercodes occurred exclusively during autumn.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.177-190
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• 2009

Species composition and abundance of marine organism in the Nakdong River estuary were investigated seasonally from November 2007 to November 2008. During the study period, a total of 169 species, 93 families, and 6 taxa were collected in the study area. Species included were 2 species in Bivalvia, 11 in Cephalopoda, 43 in Crustecea, 8 in Echinodermata, 6 in Gastropoda, and 99 in Pisces. The seasonal dominant species in number of individuals were Acropoma japonicum in autumn, Apogon lineatus in winter, Siphonalia spadicea fuscolineata in spring, and Crangon hakodatei in summer. Dominant species in abundance were Chelidonichthys spinosus in autumn, Liphius litulon in winter and spring, and Raja kenojei in summer. The number of species and their abundance, the species composition, and the diversity indices fluctuated with seasons. The organisms were divided into 17 groups by seasonal variation using a self-organizing map.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.202-220
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• 1997

A total of 57 species of fish species was collected by a trawl from the eelgrass bed in Kwangyang Bay. The dominant species were Pholis nebulosa, Syngnathus schlegeli, Leiognathus nuchalis, Pseudoblennius cottoides, Sebastes inermis, Favonigobius gymnauchen, which accounted for 69.9% of the total numbers of fish collected. Fish collected in the study area were primarily small fish species or early juveniles of large fish species. Only about 10% of fishes which were collected in the eelgrass bed exceeded 15cm in standard length. Seasonal variations in both species composition and abundance were major characteristics in the study area. The peak abundance occurred in spring, while the number of species was the highest in fall. However, both the number of species and abundance of fishes showed the lowest values in winter. High species diversity indices were observed in fall. Temperature, eelgrass standing crop and abundance of food organisms influenced seasonal changes of the fish community in the study area. More abundant and more diverse fishes were collected during nighttime than daytime.

• ALGAE
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• v.19 no.2
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• pp.149-151
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• 2004

Freshwater algae make up a very important portion of the autotrophic component of the aquatic food web. Therefore, the study of freshwater algal structure and biomass is central to aquatic ecosystem studies. Due to variations in cell shape and size for each species (or taxon) and survey site, cell abundance (or cell numbers per chosen volume) often leads to misrepresentation of the true importance of some species because of the great differences in size of various algae. Thus, it is necessary to investigate the freshwater algal species of a site in order to calculate the cell volume. Although direct cell counting, species volume measurement, as well as biomass calculation are time-consuming and requiring specialists in taxonomy.

• Mycobiology
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• v.45 no.2
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• pp.97-100
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• 2017

Endangered native plant habitats and populations are rapidly disappearing because of climate and environmental changes. As a representative, the abundance of the first-class endangered wild plant, Cypripedium japonicum, has been rapidly decreasing in Korea. The purpose of this study was to evaluate the distribution of rhizosphere and endophytic fungi on C. japonicum in its native habitat. A total of 440 rhizosphere and 79 endosphere fungi isolates were isolated and identified on the basis of their molecular characteristics. Sixty-five genera and 119 fungi species were identified in this study. The genus Trichoderma showed the highest abundance among both rhizosphere and endosphere fungi. Mortierella, Hypocrea, and Penicillium spp. were also relatively dominant species on C. japonicum. The community structures of rhizosphere and endosphere fungi were similar, but endosphere fungi showed greater diversity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.1
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• pp.37-46
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• 2024

This study was conducted to provide the basic information on environment effects on appearance of ichthyoplankton in the Yeongsan River Estuary in Spring and Summer from 2018 to 2020. Data were obtain from the database of 'Coastal Ecosystem' in "National Survey of Marine Ecosystem." Among the abundance ichthyoplankton species, the Gobiidae spp. dominated, accounting for 85% of the total abundances with the secondary dominant species being the Parablennius yatabei, representing 3% of the abundances. Cluster analysis results revealed a composition differentiated between spring and summer. The Yeongsan River Estuary is known to be significantly influenced by the opening and closing of estuarine gates. In this study, the fluctuation in the number of occurrence groups and abundance among the years and season is attributed to the phenomenon of high water temperature period and the freshwater discharge.

• Journal of Aquaculture
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• v.17 no.1
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• pp.51-57
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• 2004

Species composition and seasonal change were examined monthly with shrimp assemblage caught in the coastal waters of Solido, Korea. Samplings were conducted in Solido using a beam trawl from June 2000 to May 2001. In the study period, a total of 16 species of shrimp belonging to six families were collected. Species was dominated by Palaemon gravieri, Crangon hakodatei, Trachysalambria curvirostris and Metapenaeus joyneri. Higher abundance of shrimp occurred in September and November, and lower abundance in June. Species diversity was reached its maximum (0.82) in November and its minimum (0.06) in January. Shrimp species in the study area can be grouped into three groups on the basis of their occurrence patterns: resident, seasonal and temporary species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.829-836
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• 2017

This study investigated the species composition and abundance of floating fish eggs to determine the timing and location of spawning of fish inhabiting the coastal waters of Sagye, Jejudo Island. Eggs were collected with a Bongo net bimonthly from May 2009 to February 2010. Identifications were based on nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Eggs were determined to belong to 43 distinct taxa, 35 of which were identified to the species level. The assemblage spanned eight orders, 23 families, and 32 genera. The number of taxa collected varied from month to month, with 14 taxa (12 species) found in June 2009, 11 taxa (10 species) in October 2009, 10 taxa (nine species) each in August 2009 and February 2010, eight taxa (six species) in April 2009, and five taxa (four species) in December 2009. Five abundant species (Branchiostegus japonicus, Engraulis japonicus, Pseudolabrus sieboldi, Goniistius zonatus, and Halichoeres tenuispinis) together represented 52.8% of the total number of eggs collected during the study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.385-392
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• 2005

Seasonal variation of abundance and species composition of ichthyoplankton were studied in the coastal water off Tongyoung, Korea. Monthly samples were collected using a ring net which were towed horizontally at 4 different stations from March, 1998 to February, 1999. A total of 74 species representing 35 families and 8 orders were found. Of these species 40 species (17 families) were Perciformes. Of the fish larvae couected Engraulis japonicus, Repomucenus sp., Parablennius yatabei, Synechogobius hasta, and Tridentiger sp. were the dominant species representing $80.6\%$ in total number of individuals. The number of species was highest in August and lowest in December; number of individuals was highest in May and lowest in November. The diversity index (Shannon and Wiener Index) was highest in march, and lowest in December.