• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.1-9
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• 2019

This study investigated settlement and scouring characteristics of artificial reef reinforced with various reinforcement types to reduce settlement and scouring. Three reinforcement types were prepared: geogrid, geogrid-bamboo mat (GBM) and seaweed-pile mat (SPM). Various laboratory tests such as bearing capacity test, large size settlement test, two-dimensional flow scour test were performed according to different soil types (sand, silt, clay). Laboratory test results indicated that bearing capacity of seabed with a reinforced artificial reef increased and its settlement and scour depth reduced for all reinforcement types. Especially, reinforcement effect tends to be greater in clay soft ground rather than sand and silt grounds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.469-477
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• 2004

This study examined distributional patterns of Asterias amurensis in Tongyeong, the central South Sea of Korea. The density of the sea star was estimated at 10 chosen sites in the inner and the outer parts of the Tongyeong coast from December 2000. The mean density of the species in this area was $2.4ind./m^{2}$. The seasonal surveys conducted at 3 arbitrary chosen sites (i.e., sea cage, reef and soft sediment) also showed that the abundance of the species at the sea cage site $(density:\;3.6\;ind./m^{2};\;biomass:\;250.7\;gwwt/m^{2})$ was significantly higher than at the reef site $(density:\;1.7\;ind./m^{2};\;biomass:\;63.5\;gwwt/m^{2})$ and the soft sediment site $(density:\;0.4\;ind./m^{2};\;biomass:\;18.9\;gwwt/m^{2})$. Densities were higher at sea cages areas than at reefs and soft bottom sites. At sea cage site, A. amurensis population exhibited a strong aggregated distributional pattern. In contrast, at reef and soft bottom sites, A. amurensis population showed a random distributional pattern. The spatial difference in prey species and its abundance was the primary factor determining the spatial heterogeneity of the sea star in its behavior characteristics. Experiments on the feeding preference indicated that A. amurensis had a strong selectivity on its prey, but this selectivity varied between populations living in different sites. In particular, A. amurensis populations at the reef site showed a strong selectivity on various sessile and mobile animals living in reef areas, suggesting that these animal groups may play a role as "windows for the survival of A. amurensis". These results suggest that the distribution of A. amurensis in Tongyeong is closely associated with abundance of prey species and the bottom composition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2307-2312
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• 2014

Artificial reef refers to various structures that facility to construction field format and spawning of marine organisms, sea ranch, forest of the sea, and sea jungle artificially in water, Build a production stable base of marine products, thereby contributing to an increase in the income of fishermen. In the management of an artificial reef, the calculation of the number of square reefs may be that it is a method to perform the submersible is an important part of maintenance is correct. However, cost and diving personnel, depending on the diving situation, there is a difficult thing to implement to coast across the country. Therefore, In this study, We calculated the volume using the multi-beam Echo Sounder and side scan sonar for the reefs of the rectangle are the existing installation. And proposes the improvement of the estimation in accordance with the volume coefficient reef.

• ALGAE
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• v.28 no.4
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• pp.365-369
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• 2013

The objective of this study was to determine the optimal blade size and timing to transplant seed-stock of Ecklonia cava Kjellman onto the reef structure. We used the modified artificial stepped reef structure. A total of 14 units (3.0 m length ${\times}$ 3.5 m width ${\times}$ 1.1 m height) were deployed 7-8 m deep under the water to examine the optimal blade size and timing to transplant seed-stock of E. cava onto the structures. Sporophytes of E. cava <1 cm in length were all died within 1 month of transplantation. The blades of 5-10 cm in length which were transplanted in March 2007 survived and grew well on the artificial reefs. Growth rates of 5-10 cm size class were higher than those of longer blade sporophytes (20-30 cm size class, transplanted in April) while the survival rates showed no difference between the classes of blade size. Both classes of 5-10 and 20-30 cm in length grew until July, and a reduction in size had occurred in September. These results indicate the importance of the blade size of E. cava and timing for successful transplantation of the seaweed on artificial reef structures.

• Journal of Fisheries and Marine Sciences Education
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• v.11 no.1
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• pp.59-68
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• 1999

The effectiveness of fishery resources enhancement of artificial reef settled in the coast of Cheju Island was determined by using the samples collected by scuaba and caught by the trammel net. The obtained results are summarized as follows; 1. Six types of shellfish were found in the artificial reef area, and the amount of shellfish living in that area was $490{\sim}3,483g/m^2$ according to our research. This shows a high density of shellfish in that area. 2. Ten types of seaweeds were found in the artificial reef area, and the reef living in that area was abundant, with $3,556{\sim}10,550g/m^2$. 3. The amount of a catch of fish in the artificial reef area was 3.5~21.4 times more than in the control area. This result shows the high productivity in that area.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.615-625
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• 2021

The coastal areas around Palau Island and Tonga Island, near the Pacific equator, consist of coral reefs, mangrove and seaweed. In particular, understanding the optical properties of sea surface water in coral reef habitats helps improve the accuracy of remote sensing based habitat mapping and identify tropical ecosystem characteristics. Here, we collected spectral characteristics of sea surface water of Palau Island and Tonga Island and analyzed the concentration of suspended matters, absorption coefficient, and remote sensing reflectance to understand the seawater characteristics of the coral reef habitats. Based on the results of the suspended matter concentration analysis, we developed and verified an empirical algorithm to derive the concentration from satellite data using remote sensing reflectance of three bands, 555, 625, 660 nm, showed a high determinant coefficient, 0.98. In conclusion, coral reef habitats in tropical regions are characterized by CASE-I water in terms of the marine optics with oligotrophic properties, and require monitoring using continuous collection and analysis of field data.

• Animal Systematics, Evolution and Diversity
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• v.20 no.2
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• pp.109-140
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• 2004

Seven new species of cope pods associated with marine invertebrates are described from the Great Barrier Reef, Australia. They are Panjakus bidentis from the scleractinian Pocillopora verrucosa (Ellis and Solander), Scyphuliger humesi, S. vicinus and S. placidus from the scleractinian Acropora squarrosa (Ehrenberg), Doridicola parapatulus from the nudibranch Glossodoris atromarginata (Cuvier), Ruhtra germinata from an unidentified alcyonacean coral, and Collocheres oribullatus from the crinoid Comanthina belli (Carpenter).

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.28-34
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• 2001

The experimental studies for the artificial reef (AFR) subsidence characteristics in the unsteady flow field and in the unsteady flow-wave field were carried out. The difference of scou $r_sidence characteristics between in the steady flow field and in the unsteady flow field wad discussed and also the long-term subsidence characteristics in the unsteady flow field were investigated. AFR subsidence characteristics was discussed with Keulegan - Carpenter number(KC), Reynolds number (Re),. Shields number (Sn) and dimensionless time (t/Tt). And the difference of subsidence characteristics between in the unsteady flow and in the unsteady flow-wave field was discussed.ed.

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.29-29
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• 2001

The experimental studies for the artificial reef (AFR) subsidence characteristics in the unsteady flow field and in the unsteady flow-wave field were carried out. The difference of scour/subsidence characteristics between in the steady flow field and in the unsteady flow field wad discussed and also the long-term subsidence characteristics in the unsteady flow field were investigated. AFR subsidence characteristics was discussed with Keulegan - Carpenter number(KC), Reynolds number (Re),. Shields number (Sn) and dimensionless time (t/Tt). And the difference of subsidence characteristics between in the unsteady flow and in the unsteady flow-wave field was discussed.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.33-38
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• 2001

The subsidence characteristics of artificial reef (AFR) in the unsteady flow such as tidal flow were investigated. The scour and subsidence characteristics were confirmed in the steady flow field. In a main study, the interaction of "Flow - Sediment Movement - Structure Behavior" and scou $r_sidence mechanism were discussed int he unsteady flow field. AFR subsidence characteristics was discussed with Reynolds number(Re*), Shields number(Sn*), dimensionless acceleration of flow (af/g) and dimensionless time (t/T). Most of all, the continuous AFR subsidence from the scour was occurred by periodic behavior of AFR. This behavior is result from the asymmetric ground, and is influenced by maximum velocity, duration time and direction of flow.ow.