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with good recovery in February, continuing through May. The downcurrent stations did 

 not experience a decline until February and there was substantial recovery by May. The 

 upcurrent reference stations did not show declines in density in either November or 

 February, but exhibited gradual increases in density through the four seasons. 



Several species showed this or a slightly different pattern of seasonal change 

 in abundance. The most dramatic population decline was experienced by the corophiid 

 amphipod Erichthonius rubricornis , an epifaunal suspension feeder. Most of the population 

 changes observed near the rig site can be correlated with changes in sediment grain size 

 characteristics. This probably was due primarily to the scouring action of winter storms, 

 particularly between November, 1981 and February, 1982. It also is possible that 

 accumulation of drill cuttings near the rig between November and February could have 

 contributed to the population changes observed. Evidence of drilling fluid accumulation 

 did not occur until May, by which time most species had shown substantial recovery. 

 Thus, no short-term adverse changes in the benthic infaunai community have been 

 identified to date which can be related to accumulation of materials from drilling 

 discharges in sediments near exploratory rigs. 



6.6 Bottom Still Photographs 



Bottom still photographs taken at regional and site-specific stations provided 

 visual evidence of seasonal changes in the surface texture and color of the bottom, and 

 patchiness of epifaunal invertebrates and demersal fish. No evidence of drill cuttings or 

 drilling fluid accumulation on the bottom was found in any photograph. This is not 

 surprising, because the chemical evidence provided by Bothner et al., (1982) indicates that 

 only very small amounts of these materials accumulated per unit area of bottom near the 

 rig sites. 



Several regional stations, particularly those at the same depth interval, 

 showed similarities in surface topography, amount of detritus or biological cover, and 

 sediment type. Biological cover was most dense in July and May. There was evidence of 

 bottom scour, including pronounced ripple marks, in November and particularly February 

 at many stations. Bottom scour was most evident at the shallower stations. 



7. KEY PARTICIPANTS IN THE PROGRAM 



The Georges Bank Benthic Infauna Monitoring Program has been a 

 collaborative effort of nearly 100 scientists and technicians. The program leaders are: 



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