Michael Foley, Yuko Stender, Amarjit Singh, Paul Jokiel, Ku‘ulei Rodgers


A multifunctional structure is being designed for the Kahului Harbor, Maui, Hawai‘i, to mitigate operational problems caused by wave energy while also providing coral reef habitat. There is limited information on how the design of a coastal structure can be manipulated to enhance the ecology of targeted coral communities. To inform the ecological engineering of an artificial coral reef, the relationship between substrate characteristics and coral colonization was investigated through coral recruitment experiments and study of field conditions. Three concrete compositions that differed by the use of basalt, limestone, or recycled aggregates were tested in field and laboratory experiments to determine the impact of each substrate on the recruitment of juvenile hermatypic corals. The concrete test plates were deployed in three environments for a period of about one year, after which the coral recruits on each plate were identified and counted. No significant difference was found in the average number of coral recruits on the concrete mixed with basalt, limestone and recycled aggregate (60 ± 9, 83 ± 17 and 77 ± 14, respectively). Significant differences in coral recruitment were found due to the laboratory tanks, deep water, and shallow water field tests environments (86 ± 11, 135 ± 15 and 4 ± 1, respectively). These results highlight the importance of environmental site conditions for the development of coral reef habitat. A field study was conducted in the vicinity of purposed artificial reef site to relate the topographic features of the surrounding environment to the levels of live coral coverage. The benthic zone was surveyed using a drop camera system and by divers who recorded in-situ observations. Of the area surveyed, the highest density of coral coverage (>90% cover on 60% of the area) was found on an adjacent natural reef area that was characterized by spur and groove geomorphology with a high degree of macro- and microtopographic complexity. In contrast, sparse coral cover was discovered on the concrete armor units of the existing east breakwater structure, while no live coral cover was observed on the sand and carbonate rubble substrate at the proposed artificial reef location. The high degree of coral coverage on the adjacent natural reef suggests that the artificial coral reef design should emulate the natural spur and groove structure with regards to topographic complexity on multiple scales, orientation with wave direction, and water depth.


submerged breakwater; multipurpose reef; coral recruitment; mitigation; benthic survey; topographic complexity; concrete mix design; shoreline protection; armor units

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Anderson, J., K. Milliken, D. Wallace, A. Rodriguez, and A. Simms. 2010. Coastal impact underestimated from rapid sea level rise, Eos, 91, 205-206.

Baine, M. 2001. Artificial reefs: a review of their design, application, management and performance, Ocean & Coastal Management, 44, 241-259.

Battista, T.A., B.M. Costa, and S.M. Anderson. 2007. Shallow-water benthic habitats of the main eight Hawai'ian Islands (DVD), NOAA Technical Memorandum NOS NCCOS 61, Biogeography Branch, Silver Spring, Maryland.

Bernal-Sotelo, K. and A. Acosta. 2012. The relationship between physical and biological habitat conditions and hermatypic coral recruits abundance within insular reefs (Colombian Caribbean), Revista de Biologia Tropical, 60, 995-1014.

Burt, J., A. Bartholomew, and P.F. Sale. 2011. Benthic development on large-scale engineered reefs: a comparison of communities among breakwaters of different age and natural reefs, Ecological Engineering, 37, 191-198.

Burt, J., A. Bartholomew, A. Bauman, A. Saif, and P.F. Sale. 2009. Coral recruitment and early benthic community development on several materials used in the construction of artificial reefs and breakwaters, Journal of Experimental Marine Biology and Ecology, 373, 72-78

Cesar, H.S.J., and P.J.H. van Beukering. 2004. Economic Valuation of the Coral Reefs of Hawai'i, Pacific Science, 58(2), 231-242

Chapman, M.G. and A.J. Underwood. 2011. Evaluation of ecological engineering of “armoured” shorelines to improve their value as habitat. Journal of Experimental Marine Biology and Ecology 400, 302-313

Clinton, B. 1998. Executive Order 13089--coral reef protection, Weekly Compilation of Presidential Documents, 34(24), 1099.

Demirbilek, Z., L. Lin, W.C. Seabergh, H. Mase, and J. Zheng. 2009. Laboratory and numerical studies of hydrodynamics near jetties, Coastal Engineering Journal, 51, 143-175.

Dupont, J.M. 2008. Artificial reefs as restoration tools: a case study on the West Florida Shelf, Coastal Management, 36:5, 495-507

Ferse, S.C.A., M.M. Nugues, S.B.C. Romatzki, and A. Kunzmann. 2013. Examining the use of mass transplantation of brooding and spawning corals to support natural coral recruitment in Sulawesi/Indonesia. Restoration Ecology, 21, 745-754.

Foley, M., and A. Singh. 2011. Engineered reef for shoreline and harbor protection, In: Modern Methods and Advances in Structural Engineering and Construction, ISEC-6.

Gilliam, D.S. 2012. A Study to Evaluate Reef Recovery Following Injury and Mitigation Structures Offshore Southeast Florida: Phase II. Nova Southeastern University Oceanographic Center. Dania Beach, Florida, 77 pp.

Google Inc. 2013. Google Earth (Version [Software].

Hoegh-Guldberg, O. 2011. The impact of climate change on coral reef ecosystems, In: Coral reefs: an

ecosystem in transition, Springer Science+Business Media, 391-403.

Hoeke R.K., P.L. Jokiel, R.W. Buddemeier, and R.E. Brainard. 2011. Projected changes to growth and

mortality of Hawai'ian corals over the next 100 years, PLoS ONE, 6(3): e18038.

Hodgson, G. 1985. Abundance and distribution of planktonic coral larvae in Kāne‘ohe Bay, O‘ahu,

Hawai‘i, Marine Ecology Progress Series, 26, 61-71.

Hughes, T.P., A.H. Baird, D.R. Bellwood, M. Card, S.R. Connolly, C. Folke, R. Grosberg, O. Hoegh-

Guldberg, J.B.C. Jackson, J. Kleypas, J.M. Lough, P. Marshall, M. Nystrom, S.R. Palumbi, J.M. Pandolfi, B. Rosen, and J. Roughgarden. 2003. Climate change, human impacts, and the resilience of coral reefs, Science, 301, 929-933.

Jokiel, P.L. and J. Naughton. 2001. Coral reef mitigation and restoration techniques employed in the Pacific Islands: II. Guidelines, Oceans 2001 MTS/IEEE Proceedings, IEEE, 313-316.

Jokiel, P.L. 2008. Biology and ecological functioning of coral reefs in the main Hawai'ian Islands, B.M. Riegl and R.E. Dodge (eds.), Coral Reefs of the USA, 489 – 517.

Kolinski, S.P, and E.F. Cox. 2003. An update on modes and timing of gamete and planula release in Hawai‘ian scleractinian corals with implications for conservation and management, Pacific Science, 57, 17-27.

Kosmatka, S.H. and W.C. Panarese. 1988. Design and Control of Concrete Mixtures, 13th ed., Portland Cement Association, Skokie, Illinois, 205 pp.

Mohammed, T.U., H. Hamada, and T. Yamaji. 2003. Marine durability of 30-year old concrete made with different cements, Journal of Advanced Concrete Technology, 1, 63-75.

Nakamura, T. 2010. Importance of water-flow on the physiological responses of reef-building corals, Galaxea, Journal of Coral Reef Studies, 12, 1-14.

Naughton, J. and P.L Jokiel. 2001. Coral reef mitigation and restoration techniques employed in the Pacific Islands: I. Overview, Oceans 2001 MTS/IEEE Proceedings, IEEE, 306-312.

Nozawa, Y., K. Tanaka, and J. Reimer. 2011. Reconsideration of the surface structure of settlement plates used in coral recruitment studies, Zoological Studies, 50, 53-60.

Okihiro, M., R.T. Guza, W.C. O'Reilly, and D.D. Mcgehee. 1994. Selecting Wave Gauge Sites for Monitoring Harbor Oscillations: A Case Study for Kahului Harbor, Hawai‘i, Scripps Institution of Oceanography, University of California, La Jolla, California, U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi, 27 pp.

Perkol-Finkel, S. and Y. Benayahu. 2005. Recruitment of benthic organisms onto a planned artificial reef: shifts in community structure one decade post-deployment, Marine Environmental Research, 59, 79-99.

Perkol-Finkel, S., F. Ferrario, V. Nicotera, and L. Airoldi. 2012. Conservation challenges in urban seascapes: promoting the growth of threatened species on coastal infrastructures. Journal of Applied Ecology, 49, 1457-1466.

Rogers, J.S., S.G. Monismith, F. Feddersen, and C.D. Storlazzi. 2013. Hydrodynamics of spur and groove formations on a coral reef, Journal of Geophysical Research: Oceans, 118, 1–15.

Sargent F.E., D.G. Markle, and P.J. Grace. 1988. Case Histories of Corps Breakwater and Jetty Structures, Report 4, Technical Report REMR-CO-3, U.S. Army Corps Engineers, Pacific Ocean Division, Vicksburg, Mississippi, 50 pp.

Seleem, H.E., A.M. Rashad, and B.A. El-Sabbagh. 2010. Durability and strength evaluation of high- performance concrete in marine structures, Construction & Building Materials, 24, 878 -884.

Spieler, R.E., D.S. Gilliam, and R.L. Sherman. 2001. Artificial substrate and coral reef restoration: what do we need to know to know what we need, Bulletin of Marine Science, 69, 1013-1030.

Stender, Y., P.L. Jokiel, and K.S. Rodgers. 2014a. Thirty years of coral reef change in relation to coastal construction and increased sedimentation at Pelekane Bay, Hawai‘i, PeerJ, 2:e300.

Stender, Y., M. Foley, K. Rodgers, P. Jokiel, and A. Singh. 2014b. Ecological and management considerations for a multi-objective submerged breakwater: a potential for harbor protection and habitat enhancement for coral reefs in Kahului, Maui. In Prep.

Storlazzi, C.D., A.S. Ogston, M.H. Bthner, M.F. Field, M.K. Presto. 2004. Wave- and tidally-driven flow and sediment flux across a fringing coral reef: Southern Molokai, Hawai‘i, Continental Shelf Research, 24, 1397-1419.

Sundar, V., and S.A. Sannasiraj. 2013. Kahului Harbor: Numerical modeling on artificial submerged breakwater, Final Report, Department of Ocean Engineering, Indian Institute of Technology, Madras, India.

Svane, I. and J.K. Petersen. 2001. On the problems of epibioses, fouling and artificial reefs, a review, Marine Ecology, 22,169-188

Thompson, E.F., and Z. Demirbilek. 2002. Wave Climate and Wave Response, 2025 Plan, Kahului Harbor, Maui, Hawai‘i, Technical Report, Coastal and Hydraulics Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi, 78 pp.

U.S. Department of Commerce. National Oceanic and Atmospheric Administration. National Marine Fisheries Service. 2014. Endangered and threatened wildlife and plants: Final listing determinations on proposal to list 66 reef-building coral species and to reclassify Elkhorn and Staghorn corals, 50 CFR Part 223, Docket No. 0911231415-4826-0.4 RIN 0648-XT12,

U.S. Environmental Protection Agency. 2004. Memorandum of Agreement: The Determination Of Mitigation Under The Clean Water Act Section 404(B)(1) Guidelines, ml#6

Wamsley, T., H. Hanson, N.C. Kraus. 2002. Wave Transmission at Detached Breakwaters for Shoreline Response Modeling, ERDC/CHL CHETN-II-45, U.S. Army Corps of Engineers.

Ziemann, D. 2003. Kahului Commercial Harbor 2025 Master Plan Environmental Assessment: water quality, marine biological and natural resources impacts assessment, Oceanic Institute, Waimanalo, Hawai‘i, 47 pp.