215 



Medina strip net on this back portion is to keep the purpoises from 

 getting tlieir noses caught in there when they go out of the net or when 

 they panic. 



The vessel uses a process which is called backing down. This is the 

 bow of the vessel as you can see. 



As the vessel backs down, tlie portion of the net furthest away from 

 the vessel will sink so that the porpoises can then swim out. It takes a 

 skilled operator to keep the tuna inside the net and the porpoises out. 



You can see from the experiments that are going on, again it is a 

 mixed success-type thing. 



We think this is the most promising at the present time, but we are 

 experimenting with every conceivable thing, the industry and the 

 National Marine Fisheries Service. 



Mr. DiNGELL. You might help the committee by indicating to us 

 the fashion, and the place and the manner of the most acute mortality 

 for porpoises in connection with this operation at a time convenient 

 to you. 



Mr. Pollock. All right, I think. Mr. Chairman, the problem there 

 was an experiment just last week where the Medina net was not used, 

 but we had a problem of a number of porpoises drowning. Wliat they 

 did was panic from the killer whale sound and they then ran into the 

 net, as distinct from getting over it, and they got caught in the large 

 mesh. This caused a problem. 



Mr. DiNGELL. Is it not a fact that the porpoise tends to dive when 

 frightened ? 



Mr. Pollock. He will, to some extent. This Medina net, as I under- 

 stand it, goes down some 40 feet or so and is 700 feet long so the pre- 

 sumption is whenever they do try to get out and dive, they would run 

 into the smaller mesh net as distinct from the main jwrtion of the net. 



67-765 O - 71 - 15 



