The Investigation of the Hydrodynamics of an Artificial Reef - Aquaculture and the Environment: A Shared Destiny - page 79

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The Investigation of the
Hydrodynamics of an Artificial Reef
Yan Liu 1 , Guohai Dong 1 , Yunpeng Zhao 1 ,
Changtao Guan 2,3 and Yucheng Li 1
1 Dalian University of Technology
2 Yellow Sea Fisheries Research Institute
3 Key Laboratory of Fishery Equipment and Engineering
China
1. Introduction
Marine resources have been declining all over the world in recent decades. The natural reefs
of the world are experiencing higher use and pressures, resulting in anthropogenic
influences that are deteriorating coral reefs and causing poor water quality. Artificial reefs
are manmade structures that are placed on the seabed deliberately to mimic some
characteristics of a natural reef. (Jensen, 1998) . Both Japan and the United States have been
using artificial reefs for at least 200 years. The first artificial reef was deployed in Japan in
the 1700s, and the primary goal was to increase fish-catch. Nowadays, artificial reefs in
Japan involve diversified types, integrated materials, complicated structures and large-scale
design. The first documented artificial reef in the United States dates from 1830, when logs
and rocks were sunk off the coast of South Carolina to improve fishing (Williams, 2006) . In
many countries, artificial reefs have become important elements in the plans for integrated
fishery management. Diverse shapes for artificial reefs, such as cube reefs, circular reefs,
cross-shaped reefs and so on, provide favorable circumstances for fish perching, foraging,
breeding and defense from enemies. Most artificial constructions in the marine environment
consist of a variety of non-natural materials. At present, concrete is most commonly
employed as a reef material, including cubes, blocks and pipes. Concrete has also been used
in combination with other reef materials such as steel, quarry rock, tires and plastic (Baine,
2001) . Many of the world's largest artificial reefs have been deployed as part of a national
fisheries program in Japan, where large steel and concrete frameworks have been carefully
designed to withstand strong ocean currents (Seaman, 2007) . Other popular reef building
materials include natural stone and rock, the latter constructed from wide-ranging materials
including canvas, anchor blocks, and others. The different faunal assemblages associated
with artificial reefs are determined by the physical and chemical nature of the reef materials.
Walker, et al (2002) quantitatively compared the fish abundance, fish species richness and
fish biomass on artificial reef modules constructed of various materials.
There are several proposed mechanisms to explain how artificial reefs increase total biomass
production. First, an artificial reef can provide additional food and increase feeding
efficiency, and many studies have reported observations of fishes feeding at artificial reefs.