increase and attract a greater variety and abundance of motile animals 

 (Gustafson, 1972; Saloman, 1974; Maragos, et al., 1977; Courtenay, Hartig, and 

 Loisel, 1980; Holland, Chambers, and Blackman, 1980; Turbeville and Marsh, 1982). 

 Courtenay, Hartig, and Loisel (1980) surveyed a borrow site off Hallandale, 

 Florida, 7 years after dredging and found a remarkable increase in fish species 

 except for the shallow-water burrowing dusky jawfish. The absence of this fish 

 was attributed to habitat alteration. One of the earliest studies on the effects 

 of dredging was recorded by Ingle (1952) for work done at Mobile Bay, Alabama. 

 Here also, no effect on fish was observed in the region 23 to 46 meters from 

 an active dredge. 



Holland, Chambers, and Blackman (1980) reported an increase in number of 

 fish at an offshore borrow site following dredging in the vicinity of Lido Key, 

 Florida. Mean trawl catches increased after dredging ceased, which was inter- 

 preted as an increase in fish population. They related the increase in abun- 

 dance of fish to the creation of new habitat and the increase in available 

 food. Saloman (1974) observed fish fauna at Treasure Island, Florida. He 

 noticed that the abundance and diversity of fishes were higher in the borrow 

 areas after dredging ceased. Maragos, et al. (1977) noted that fish were 

 attracted to a sand mining operation in Hawaii. This was related to the un- 

 covering and suspension of food that attracted the fish. Beneficial effect of 

 dredging operations was also observed by Viosca (1958) who attributed the 

 congregation of fishes near dredges in Louisiana to better availability of food 

 and nutrients. Gustafson (1972) noted that borrow pits in San Francisco Bay, 

 California, served as a haven for many game fish such as the striped bass 

 {Rooaus saxatilis) . 



4. Effects on Corals . 



Lack of locomotion and sensitivity to reduced light renders these organisms 

 susceptible to damage, especially when unplanned, careless dredging operations 

 are conducted offshore. However, with proper planning, impacts on corals can 

 be minimized in most cases. Courtenay, Hartig, and Loisel (1980) and Marsh, 

 et al. (1980) found high abundance and diversity of reef biota, corals, alcyo- 

 narians, and sponges 7 years after a dredging operation at Hallandale Beach, 

 Florida. They concluded that in some cases corals can recover from dredging if 

 the dredging impacts are held to a minimum. 



Maragos, et al. (1977) conducted environmental surveys of an offshore mining 

 delivery system in Hawaii. They surveyed abundance, distribution, and response 

 of corals by diving observations and sampling before, during, and after a 2- 

 month field test. A "control" site was always surveyed on the basis of bio- 

 logical, physical, and geological similarities of the sand recovery sites. The 

 most significant, immediate impact of the mining operation was due to the 

 dragging of anchors and cables which collapsed adjacent reef rock and destroyed 

 some mollusks and echinoderms. Maragos (1979) resurveyed the area 5 years 

 after dredging and found some long-term impacts associated with erosion and 

 scouring at the base of coral in the dredged area. Some of the coral slumped 

 or tilted and some formed overhangs that broke off. 



Bak (1978) noticed that during a dredging operation in the Antilles the 

 light intensity decreased from about 30 percent surface illumination to 1 

 percent surface illumination at depths of 12 to 13 meters. Corals, which 



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