by 19 70 they were rare. By 19 71, no live lame llib ran chs were found 

 in the harbor. 



Effects of the effluent were less at the stations in the turning basin 

 and not detectable at the stations in the approach canal seaward of the 

 turning basin. On the grass flats to the west of the Safe Harbor 

 turning basin, echinoids were killed by the effluent but the rest of 

 the fauna and flora remained relatively stable from 1968 to 1971. 



Effusions following the start-up of the desalination plant after 

 maintenance operations caused more biological damage than effluent 

 from the normally operating desalination plant, especially at shallow 

 water stations normally not subjected to effluent. Maintenance work 

 increased as the study progressed with the result that effusions were 

 more common in the fall of 19 70 and the winter and spring of 19 71 

 than earlier in the study. 



l^en the harbor fauna was assessed in June, 19 70 there was a signifi- 

 cant difference in the deep versus the shallow fauna at all stations. 

 As the study progressed, and effusions became more common, the differ- 

 ences between the shallow and deep stations became less pronounced. 



By the spring of 19 71, effusions had depleted the shallow water Safe 

 Harbor fauna and the shallow stations were not greatly different from 

 the deep stations. In the turning basin, however, and at the station 

 in the innermost portion of the harbor, the shallow stations remained 

 different from the deep stations throughout the study, indicating the 

 impact of the deeper effluent stratum was more extensive, geographically, 

 than the impact of the periodic effusions. 



Effusions, however, caused more deaths of experimental animals than the 

 effluent, even at stations in the turning basin. Between October, 19 70 

 and October, 19 71 no experimental animals died at the biological stations 

 when the plant was operating normally. Prior to October, 19 70 numerous 

 experimental animals died during normal operating conditions and it was 

 evident that 'normal' effluent was deleterious. Later in the study, 

 however, effusions became so frequent that the test organisms were 

 eliminated by transient peaks of contaminants before the long-term 

 effects could cause mortalities. The success of at least two and possibly 

 three of the more abundant organisms in Safe Harbor can be attributed to 

 their ability to avoid the transient peaks of contaminants associated 

 with effusions from the desalination plant and their ability to tolerate 

 the steady-state conditions. Fish were able to swim out of the turbid 

 effusions and were observed doing so. Smaller species of fishes which 

 fled into holes and crevices in the canal wall did not escape and some 

 of these were found to have hepatic lesions similar to those found in 

 fish experimentally poisoned with copper. 



Barnacles, by sealing their shells with an operculum, also avoided the 

 toxic effusions and were able to inhabit rocks immediately in the path 



