holes in the winter may attract fish, but low dissolved oxygen during the summer 

 may result in low fish populations. The majority of the offshore borrow pits 

 observed by CERC did not accumulate organics or have low dissolved oxygen. 

 Saloman, Naughton, and Taylor (1982) and Culter and Mahadevan C1982) noted 

 rapid filling of offshore borrow pits at Panama City Beach, Florida, and no 

 water quality problems. Turbeville and Marsh (1982) noted that a borrow pit 

 off Hillsboro Beach, Florida, had not filled with sediments after 5 years and 

 water quality was generally good in the pit. Courtenay, et al. (197A) and 

 Courtenay, Hartig, and Loisel (1980) observed no significant water quality 

 problems at a borrow pit off Broward County, Florida. These contrasting 

 conditions of the various borrow pits were related to the differing physical 

 and chemical conditions, i.e., currents, sediment movement, and water quality. 

 This indicates a need for a thorough understanding of the area proposed as a 

 borrow site before predicting impacts. 



X. FAUNAL RECOVERY OF BORROW PITS 



Predictions of the recovery rate of animals in a borrow pit following 

 dredging vary. The reason for the variation is that faunal recovery depends 

 on many biotic and abiotic factors and their interaction. 



1. Benthic Communities . 



Repopulation of a dredged area by benthic animals will depend on the depth 

 of the borrow pit, the new surface sediments, and the water quality of the 

 borrow pit. Suitable borrow pits will be recolonized by migration of animals 

 from adjacent areas; however, the reestablished population may not be the same 

 abundance or species composition as before dredging. 



Saloman (1974) observed benthic life in borrow pits dredged off Treasure 

 Island, Florida, in a relatively stable environment (i.e., low waves and 

 current) . He found that the macrobenthic fauna in 3-year-old borrow pits were 

 very small in size and low in abundance and diversity compared to adjacent 

 control areas. Ke hypothesized that as the benthic animals grew larger they 

 sank into the soft sediments that had accumulated in the pits or died due to 

 low dissolved oxygen and high levels of sulfide. Recovery was not apparent. 

 Taylor Biological Company (1978) studied the same borrow pits off Treasure 

 Island, Florida, 4 years after dredging and found the pits were filling with 

 soft sediment and were in a slow state of recovery. They predicted it would 

 take 10 years or more for the borrow pits to completely recover to predredging 

 conditions. 



In contrast, Saloman, Naughton, and Taylor (1982) studied borrow pits 

 before dredging and for 1 year after dredging at Panama City Beach, Florida. 

 They observed an immediate decline in the bottom communities followed by a 

 rapid postconstruction recovery. Recovery was complete after about 1 year. 

 Culter and Mahadevan (1982) studied the same borrow areas as Saloman, Naughton, 

 and Taylor (1982) and concluded, based on benthic community analysis and 

 sediment parameters, that there were no significant differences in benthic 

 populations between the borrow and surrounding areas. However, they did con- 

 clude that because their control sites were in deeper water than the borrow 

 sites and the benthic populations were different, the dredging effects were 

 not completely clear. 



29 



