were shaded and unable to escape the sediment, lost their zooxanthellae and 

 died. Additionally, the calcification rate in some corals was also suppressed. 



Marszalek (1980) also studied the environmental impact of siltation 

 (generated by dredging) on coral communities in Dade County, Florida. The 

 stony corals were affected mostly by the accumulation of silt and turbidity. 

 The same author recorded the results of dredging in 1978 near Haulover Cut, 

 Miami Beach, Florida, where corals were surveyed after approximately 1 year. 

 Soft corals and sponges showed no signs of damage, but hard corals exhibited 

 bleaching and reduction in colony size. Marszalek attributed the effects on 

 hard corals to the length of exposure to turbidity and sedimentation, rather 

 than to just sedimentation. The lack of adverse effects on soft corals was 

 perhaps due to their upright body, flexibility, and the current action 

 removing the silt. 



Spadoni (1978, 1979) reported on the effects of dredging on coral growth 

 in connection with a beach nourishment project at Delray Beach, Florida. Five 

 reef stations were monitored before, during, and after the beach nourisbjnent 

 project. Water and sedimentation samples were also collected and diver obser- 

 vations were made throughout the monitoring period to investigate the effects 

 of the dredge cutterhead and positioning of the anchor on nearby corals. The 

 investigator concluded that turbidity and sedimentation had no observable 

 effects on reef corals. However, reef damage did occur due to the dredge 

 anchor and anchor cable dragging across the reef. The damage consisted of 

 uprooted soft corals, fragmented sponges, and overturned or scarred coral 

 heads. The most severely damaged area was that with the highest reef topog- 

 raphy . 



5. Effects on Sea Turtles . 



The effect of borrowing on sea turtles is unknown because of the lack of 

 information on this species. Little is also known about the young turtles 

 that return to the ocean soon after their birth on the beaches. There is 

 concern that the turtles will be affected by dredging machinery at inshore and 

 offshore borrow sites, especially because of their relatively slow locomotion, 

 and they are known to hibernate in some deep navigational channels during the 

 winter (Carr, Ogren, and Moven, 1980). Future borrowing projects involving 

 sea turtles should be coordinated with U.S. Fish and Wildlife Service and 

 National Marine Fisheries Service. 



6. Water and Sediment Quality . 



Nutrient release as a result of dredging does not appear to be a major 

 problem offshore because of dispersal by currents and dilution. However, this 

 may be a problem if nourishment material is taken from confined areas in the . 

 inshore. Changes in water and sediment quality at inshore and offshore borrow 

 pits have been identified as potential problems. Deep borrow pits in stable 

 areas can result in the accumulation of organic material and the stagnation of 

 bottom water in the pits. Saloman (1974) and Taylor Biological Company (1978) 

 observed this condition in offshore borrow pits at Treasure Island, Florida. 

 Pisapia (1974), who reviewed the literature on the impacts of inshore dredge 

 holes, reported that inshore dredge holes in areas where currents are low gen- 

 erally accumulate high concentrations of organic material and are considered 

 poor-quality aquatic habitats. He also noted that warm waters in the dredged 



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