Cathodic protection uses sacrificial anodes placed on "sleds" at 

 random intervals around the platform legs and resting on the bottom. A 

 current is put through the connecting wires to the anodes from 

 rectifiers which are on board the platforms. The current produces an 

 ion flow with the result that the sacrificial anode material corrodes 

 away instead of the platform leg. The amount of amperage through the 

 system varies from 400-1800 amps for 4 to 6 rectifiers. This could be 

 enough current to affect marine mammals, at least to the point of 

 alerting them of the presence of an electric field. There has not been 

 much research done in this area. 



The only noticeable effect of any OCS operation on marine mammals 

 was that they would dive when a helicopter flew over. This occurs 

 daily, but not constantly during the day. Therefore this effect may be 

 minimal . 



From all reports, OCS development in the Cook Inlet does not seem 

 to be affecting the marine mammal populations. 



Conclusion 



At present, not enough information is available about the behavior, 

 tolerance, and adaptability of individual species to evaluate the effect 

 of OCS platforms on marine mammals conclusively. The present short 

 study did not discover any adverse effects on large or small whales or 

 dolphins. Anecdotal information tends to indicate that the whales 

 either ignore the platforms or easily avoid them without appreciable 

 change in behavior. Smaller cetaceans and pinnipeds may even find an 

 attractive environment around the platforms. Some caution should be 

 applied because without sufficient baseline information and adequate 

 time for studying any long term effects these results cannot be 

 interpreted in the proper perspectives. 



Recormiendations 



The following changes in experimental design of this project are 

 recommended in order to obtain more reliable data to study the effects 

 of OCS platforms on marine mammals: 



1. Pre-Development Studies. 



Conduct interview programs and observation studies, ideally 

 aerially or nautically, to get baseline information in areas 

 where OCS lease sales are proposed. Conduct studies prior to 

 and during exploration and preliminary drilling, and at some 

 time after drilling has been implemented. 



2. Place Trained Observers on the Platforms. 



Individuals who are trained to identify various species of 

 marine mammals should be placed on each platform to be used in 

 the study with adequate instrumentation such as sextant. 



C-27 



