• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.3
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• pp.208-214
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• 2008

This study monitored a variety of marine communities during monthly or bimonthly censuses from February 1999 to August 2000. The communities investigated included artificial reefs composed of various substrates, which were placed on an area of sandy bottom at 8, 10, and 13m depths in Muronohana, Ikata, Shikoku, Japan. Economically important shell fishes, such as the turban shell and abalone, appeared on the artificial reefs after 1 month of construction. Shell fishes were recorded at levels of five to 20 individuals per reef. A total of 37 species (4 orders, 19 families) were identified during the experimental period. Apagon semilineatus, Trachurus japonicus, Pteragogus sp., and Pterogobius elapoides accumulated over an average of 100 individuals during the study period. Apagon semilineatus, Pteragogus sp., and P. elapoides accumulated over 1,000 individuals on all artificial reefs in May 1999. Trachurus japonicus reached well over 500 individuals in the artificial iron reef during June and July 2000. Higher monthly variation in fish abundance occurred during periods of high temperature, as compared to periods of low temperature between December 1999 and March 2000. More fish were observed in the artificial iron reef than in the artificial concrete reef, because the former offered a broader inner space and the shadows of the roofs served as a shelter for fish.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.280-288
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• 2019

A submerged breakwater is one of the coastal structures used to reduce wave energy and coastal erosion. However, a submerged breakwater has a negative aspect in that a strong rip current occurring around an open inlet due to a difference in mean water levels at the front and rear sides of the structure leads to scouring. Such scouring has a bad effect on its stability. In order to eliminate this kind of demerit, this study investigated an artificial reef of the overflow type with openings. We also developed a program where the flows around the artificial reef of the overflow type could be analyzed numerically. An unstructured grid system was used to cover the various geometries, and the level set method was applied to treat the movement of the free surface. To verify these numerical schemes, hydraulic physical tests were performed on the submerged breakwater and double breaking type artificial reef. Then, the wave height and velocity distribution around the reef were examined using the experimental results. Comparisons between the results of hydraulic and numerical tests showed reasonable agreement.

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.23-32
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• 2019

This study investigated the scour characteristics of artificial reef according to unreinforced and reinforced artificial reefs through laboratory test and numerical analysis. In this study, geogrid was used as a reinforcement of seabed. Three different reinforced areas were selected; one time, three times and five times bottom area of artificial reef. Two-dimensional water channel test was carried out to investigate scour patten of sand and silt grounds. Numerical analysis was also performed to see the velocity vector and scouring patten around artificial reef which was same condition with experiment. The numerical results were in good agreements with the experimental test results. It was found that the geogrid-installed soft ground under artificial reef tends to reduce scour, compared to unreinforced soft ground.

• The Journal of Fisheries Business Administration
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• v.44 no.3
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• pp.103-109
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• 2013

This paper analyzed that the economic effectiveness of the artificial fish reef project in the Tae-an Marine Ranching. Benefit-cost(B/C) model used to indicate the effects of economic valuation. B/C model is based on the sub-models which are Benefit Cost Ratio(BCR), Net Present Value(NPV) and Internal Ration of Return(IRR). First, the Sum of Incremental Benefit and Cost for total vessel by year in Artificial Fish Reef Area(AFRA) estimated 2,381 million won. And then, using 5.5% discounting rates and the survey data, the sub-models showed economically feasible in the all of analysis and analyzed the results as follows. BCR is 2.66, NPV is 28,014million won, and IRR is 22.78%. In conclusion, these results indicated that the artificial fish reef project in Tae-an Marine Ranching would be increase the income of fishermen as well as fish biomass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.3
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• pp.266-272
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• 2013

The objective of this study was to monitor and evaluate the schooling characteristics, including the distribution density (volume backscattering strength) and acoustic size (target strength), of commercially valuable species swimming in response to artificial reefs installed at Suyeong Man, Busan, Korea. Fish aggregations at two artificial reef areas and at a nearby natural rocky reef habitat were recorded and analyzed using a 70 kHz split-beam echo sounder and 330 kHz side-scan sonar from August to September, 2006. An underwater CCTV camera system was also used to observe marine organisms in physical contact with and swimming very close to artificial reefs. During the acoustic observations at three reef sites, useful information about schooling characteristics of fish aggregations responding to artificial reefs were obtained, but more trials are needed to confirm significant differences in schooling behavior and geographical distributions in areas containing natural reef structures and artificial reefs.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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• pp.141-147
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• 2013

An artificila fish-reef is a artificail structure installed at marine ranching under the littoral sea. The artificial fish-reefs provide the function of fish spawning ground, habitation, nursery ground, and enhance the productivity of fising industry devastated by environmental pollution. After the installation of artificila fish-reef, continuous monitoring is demanded to check the validity of artificila fish-reef plan. However, the support of follow-up management is impossible because of the lack of a huge budget and professional manpower. Therefore, the artificial fish-reef combined with IT devices can be controled IT devices through the IT artificial fish-reef management system, and collect the marine environment information for the fair management. This paper shows the example of systematization for the management of artificial fish-reef based on the marine rancing management system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.125-134
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• 1989

A wave overtopping rate from a sea dike of various toe depths is formulated based on a weir model in an unidirectional flow. To evaluate the wave overtopping rate from a seadike on an artificial reef by the weir model, a numerical procedure for predicting wave transformations including the effect of forced wave breaking on the reef is constructed. After confirming the applicability of the model by experiments with regular and irregular waves, the effect of artificial reef on wave overtopping is discussed. So-called individual wave analysis method is shown to be applicable to the wave overtopping caused by irregular waves.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.4
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• pp.220-225
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• 2007

The succession of marine benthic algae and the restoration of an artificial seaweed forest on a porous type (shaped half saw teeth) artificial reef at Jeju island, Korea was studied. Young thalli of Sargassum horneri and Ecklonia cava were attached to different artificial substrates. In general, the succession on the artificial reefs led from filamentous algae to perennial algae and involved more than 25 species that are useful fishery resources, including E. cava. Coralline algae were dominant on the artificial reefs at the Kangjung site. The maximum algal biomass on the artificial reef in October 2005 was $1,990g/m^2$ at Biyang. In conclusion, a climax community and seaweed forest can be attained one year after the substrate is constructed.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.869-872
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• 2006

By this time, various shapes and materials are used in Artificial Reef. A function of Artificial Reef is leading of fishes by adhesion of seaweeds, however, this effect was not enough. In this study, porous concrete containing function materials (protein, carbohydrates, and fat etc.) are investigated to maximize leading effect of fishes. For these, the mechanical characteristics of porous concrete are investigated with void contents and function materials. Also, the diffusion of function materials are compared to suggest the suitable content of functional material.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.169-176
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• 2016

Considering the artificial reef (AR) canyon intervals facilitated by flatly distributed placement models, the wake volumes of 25 AR sets were characterized through the following works. First, twenty-five different canyon intervals were established to investigate how the intervals affect the wake volumes of the AR placement models, each with nine cube-type ARs. Second, the element-based finite-volume method was used to facilitate flow analyses. Third, the so-called wake volume concept was adopted, and finally a reasonable placement interval was found based on the size of the wake volumes and the associated unit propagation indices. From the analysis results, it was found that a maximum wake volume of 25.18 m³ was generated when the longitudinal and transverse intervals were fixed at 6 m and 0 m, respectively. Thus, to magnify the wake volume, it is recommended that artificial reefs be placed at intervals of 6 m (3 times the reef length) in the flow direction, with no intervals in the normal direction, implicitly indicating that an intensively stacked placement model is a better option to efficiently secure a larger wake volume for the cube-type ARs.