• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.159-165
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• 2008

Intertidal benthic algal communities on the shores of Gujido and Daeyeonpyeongdo islets, Korea, were examined in October 2007. At both sites, 45 seaweeds including 7 green, 6 brown and 32 red algae were identified. The number of species at Gujido(38 species) was 1.5 times higher than at Daeyeonpyeongdo(25 species), but seaweed coverage was very similar with about 20%. Dominant seaweeds in terms of coverage and importance value were Hildenbrandtia sp., Caulacanthus okamurae, Ulva pertusa, and Gelidium amansii at Gujido and U. pertusa, Hildenbrandtia sp., Gelidium divaricatum at Daeyeonpyeongdo. The vertical distribution pattern of the seaweeds was G. divaricatum-U. pertusa, Hildenbrandtia sp.-U. pertusa, Hildenbrandtia sp., Ishige okamurae from upper to lower intertidal zone but seaweed zonations were not observed on the Gujido rocky shore. At both sites, coarsely-branched forms were the dominant functional group in species number and percent cover(among benthic algal species). The rocky shores of the two sites were dominated by crustose coralline and green algae, whose presence generally results in decreased seaweed biodiversity and community stability. Therefore, the shores of the Yeonpyeongdo islets are of considerable environmental concern and should be monitored for seaweed species composition and community structure.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.231-236
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• 2009

This study describes biological environmental characteristics in natural habitats of Haliotis diversicolor in the coastal area of Sungsanpo located in the eastern coast of Jeju-do, Korea. The field survey was monthly conducted from May 2006 to February 2007. H. diversicolor, sea urchin, turban shell and marine algae were collected by two divers using SCUBA. The species composition of demersal fishes were seasonally investigated by fish traps in 2007. During the study period, more than 67% of H. diversicolor and sea urchin were found in the depth shallower than 5 m, and more than 64% of turban shell were found in the depth deeper than 3 m. The dominant algal species in May were generally Undaria pinnatifida, Ecklonia cava, Sargassum. spp. and coralline algae. Most of demersal fishes collected by the fish traps were wrasses which have been reported as a major predator of young abalone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.265-273
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• 1986

The marine algal communities of Yonhwa-do at the southern coast of Korea were investigated in aspects to quantitative analysis of their structure and dynamics. As a result, 114 species, including 2 blue-green, 69 red, 25 brown and 18 green algae, were identified. The R/P value(2.8) is higher than that of other regions of the southern coast of Korea. Sheet and filamentous groups of the functional groups of algae showed higher composition rate in spring and summer than in autumn and winter, but coarsely branched and thick leathery groups showed an opposite tendency. Cluster analysis based on species presence suggested the existence of 5 distinct groups in spring, but 3 groups in the other seasons. The species exhibiting important value above 20 were as follows: Porphyra suborbiculata, Corallina pilulifera, Hizikia fusiforme, Sargassum thunbergii, Undaria pinnatifida, Ishige okamurai, Chondria crassicaulis, and crustose coralline algae. The coverage of algal communities composed only of crustose coralline algal complex was higher than that of other algal complex, but occurrence frequency of these two communities was indifferent. It is suggested that the occurrence in high quantity of crustose coralline algae from this area is related to grazing by herbivorous animals.

• Ocean Science Journal
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• v.41 no.3
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• pp.163-173
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• 2006

A draconematid nematode species, Dracograllus filipjevi Allen and Noffsinger, 1978, is described from the washings of shallow littoral coralline algae at Guryongpo in the eastern coast of Korea. This species is recognized by the following characteristics: larger body size, number of posterior sublateral adhesion tubes (9 in male and 12-13 in female) and subventral adhesion tubes (8-9 in male and 9-10 in female), the absence of cephalic acanthiform setae on rostrum, the presence of longitudinally areolated body cuticle with dot-like punctations, the presence of some cuticular collar in swollen pharyngeal region, the shape of amphidial fovea (large, elongate, and loop-shaped in both sexes), the absence of preanal corniform setae, and the absence of lateral differentiation on narrow body region. Morphological features of the species using differential interference contrast photomicrographs are described in detail in the present work. The is the first report of D. filipjevi in Korea.

• Animal Systematics, Evolution and Diversity
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• v.19 no.1
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• pp.95-102
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• 2003

A new species of Halacaridae, Copidognathus koreanus is recorded from the Korean coast mostly among intertidal coralline algae. The present new species comes close with C.auroroe Newell, C.curtus (Hall), C.richardi (Trouessart) and C.unolaskensis Newell. Morphological similarities and dissimilarities among them are discussed. This is the first report on the marine halacarid mite from Korea.

• Animal Systematics, Evolution and Diversity
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• v.35 no.2
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• pp.49-56
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• 2019

A new marine halacarid species of the genus Agauopsis Viets, 1927 (Acari: Halacaridae) is recorded from Jeju Island, Korea. Agauopsis tetrasetosa n. sp. belongs to the microrhyncha group in sharing one ventral and three ventromedial spines on tibia of leg I, of which two ventromedial ones are adjacent to each other, with its 20 congeneric members. Agauopsis tetrasetosa n. sp. is most similar to A. miliaris Bartsch, 2005 and A. similis Bartsch, 1979 in sharing the similar chaetotaxy of legs I-IV, positions of the second and fourth dorsal setae, and non 'H'- or 'M'-shaped costae on anterior dorsal plate. However, the new species is distinguished from them by four pairs of perigenital setae in female, the relatively anterior location of gland pores on posterior dorsal plate, and three ventral spines on the tibia of leg II. We describe the new species herein, with detailed illustrations under a differential interference contrast microscope. We also make some brief comments on the affinities between the congeneric species of the microrhyncha group and the new species, based on a tabular key to species of the group.

• ALGAE
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• v.19 no.4
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• pp.339-347
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• 2004

Seaweed community of the sub tidal rocky habitats along the coast of Geumo Archipelago in the central South Sea of Korea is described. This area is characterized by archipelago in which islets are separated by shallow bottom sediments (primary, muddy sand), and turbidity is generally high due to the resuspension of bottom sediments. The hard substrata available for algal attachment are limited to less than 10 m in depth. Thirty sites were randomly chosen along the coast from August 2003 to September 2003 and a 50 m long transect was established at each site. The transect began at a depth of 1 m and ended at the depth of 9 m. The percent cover of all species other than crustose coralline algae was estimated at 2 m depth intervals along the transect using a 0.25 m$^2$ PVC quadrat with 25 squares. Thirty-six species were identified including 6 Chlorophyta, 10 Phaeophyta and 20 Rhodophyta. Species with more than 5% mean bottom cover were Gelidium amansii, Corallina pilulifera, Amphiroa dilatata and Carpopeltis cornea, which formed dense turf-forming algal assemblages at 1-5 m depth. At all sites except S11-S15 located in the western coast of Sorido, bottom covers of seaweed species at the depth deeper than 7 m were less than 6%. The lower limit of algal assemblages was 9 m in depth. We speculate that the limited water clarity and vertical extent of hard substrata available for the settlement of seaweed species are the direct cause of reducing the diversity, abundance and distributional extent of algal assemblages in the area.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.362-372
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• 2011

The relationships among total epiphytes, algal epiphytes and eelgrass ($Zostera$ $marina$ L.) were studied at eelgrass medows from July, 1998 to July, 1999 in Yulim-ri, Yeosu, Korea. Epiphytic diatoms on eelgrass leaves were observed from July to December 1998. From the results of this study, we inferred the following three (3) conclusions : 1) As eelgrass grew older, biomass of epiphytes increased, according to relationships between the leaf length and area of eelgrass and biomass (DW, AFDW and Chl. $a$) of epiphytes. 2) According to the ratio of dry weight, ash-free dry weight and Chlorophyll of epiphytes, the algae with calcareous or siliceous skeletons, such as coralline algae or diatoms, were dominated in the epitphytic algae community. 3) The autotrophic index (AI) calculated from AFDW and Chl. $a$ of epiphytes varied from 151 to 375. However, the period of autotrophic community was shorter than heterotrophic community and the value of AI was high. From these results, we inferred that heterotrophic community, including detritus or microorganisms were dominated in the most of research period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.262-270
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• 2012

Seaweeds provide habitats in which marine animals can spawn and develop, and serve as a food supply for algaegrazing species such as sea urchins and abalone. Recently, seaweed species have disappeared from coastal ecosystems, leaving barren ground, defined as habitats that have lost their algae forests and where coralline algae containing calcium carbonate components have become encrusted on rocks. The biological causes of barren ground include grazing by herbivores and excessive seaweed harvest. The environmental harm caused by the spread of barren ground includes accelerated eutrophication following the reduction in seaweed, which plays an important role in oceanic purification. In the present study, we identified the relationships between various seaweed species and the occurrence of barren ground. Subtidal benthic macroalgal flora and community structure were observed seasonally on barren ground along vertical transects of rocky shores of Bihwa, Samchuck, and the east coast of Korea from February to November 2006. Fifty-eight seaweed species were identified, including 7 green, 15 brown, and 36 red algae species. There were between 6 and 28 species among seasons. Over the whole study period, average seaweed biomass (g wet wt $m^{-2}$) was 241.90 g, with a seasonal range of 25.26 to 760.34 g. Seaweed biomass declined with increasing seawater depth and ranged between 91.26 and 422.08 g. The vertical distribution of algae was characterized by Undaria pinnatifida and Sargassum honeri at 5 m, S. honeri and U. pinnatifida at 10 m, and U. pinnatifida and Agarum clathratum at 15 m depth. Seasonal patterns in community indices were not found. Community indices showed different patterns along vertical shoreline gradients; the dominance index increased but the richness, evenness, and diversity indices decreased with seawater depth. Sea urchin density was 8 to 24 individ. $m^{-2}$ in Bihwa. These urchin populations had significantly aggregated spatial patterns and recurrent destructive grazing appeared to be occurring.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.627-638
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• 2022

This study was conducted at a village fishing farm on 4 peaks on the main island of Jeju Island and 2 peaks on an inhabited island to compare the distribution characteristics of seaweeds along the coast of Jeju Island from May to December 2018. A total of 101 species of seaweeds were surveyed, including 13 species (12.9%) of green algae, 24 species (23.8%) of Phaeophyta, and 64 species (63.4%) of Rhodophyta. The largest number of seaweeds appeared in May and the fewest in October, showing typical features of a temperate sea area. The number of seaweed species that appeared was 66 and 65 species at the water depths of 5 m and 8 m, respectively, and the largest was 74 species at 12 m. The number of seaweeds that appeared by area was the largest at 66 species on Udo Island, an eastern island near Jeju Island, and the lowest at 27 species in Pyoseon-ri, an eastern part of Jeju Island. The important values of emerging species were high in the order of, Ecklonia cavaand Corallina crassissima at 21.1% and 20.3%, respectively, Corallina aberransat 9.2%, Amphora ephedraeaat 6.2%, and Sargassum macrocarpumat 4.4%. Among seaweeds, an average of 11.2 species of coralline algae appeared, and the mean importance value was 32.6% in the sear area. The lowest importance value was 14.7% on Udo Island, and the highest was 41.0% in Pyoseon-ri. The mean ecological evaluation index (EEI) of seaweed colonies ranged from 2.1 to 10. It was the lowest at the water depth of 12 m in Pyoseon-ri in May and June and was 7.3 or higher in other areas, indicating good condition. This study rated the standardized ecological grade I for the water depth of 12 m on Udo Island and grade II for the water depths of 5 m and 8 m in Sagye-ri and on Chujado Island. Grade III was the water depth of 5 m and 12 m in Pyoseon-ri and Guideok 2-ri and the water depth of 5 m and 8 m in Pyeongdae-ri, and grade IV was the water depth of 8 m in Guideok 2-ri.