102 



were surprised. I do not feel that the success was due entirely to the 

 net modifications. The EUzabeth GJ. is a magnificantly equipped 



ship, and her captain and crew arc supremely skilled and efficient. 

 I have never seen such a complicated operation conducted at sea. 

 and I have never seen any operation conducted at sea with such 

 perfection* 



The chase and the setting of the net are difficult procedures and 

 they were carried out superbly; and as you saw in the film, it is an 

 exciting sight. The nets are willful, tricky creatures and a great deal 

 depended on the ('.■/. captain'.- skill in using wind, waves and cur- 

 rents to help keep the net distended, on using speedboats to prevent 

 folds and buckling in the nets and on aligning and straightening 

 out the backdown area and the superapron properly. 



It is also important to have the forces on the net so well balanced 

 that the. cork line can he raised or sunk at will, to prevent losses of 

 fish should the tuna stray into the backdown area. 



The ( '.-/. lost only about 1.7 percent of her turn catch during 

 backdowns on this trip. 



The combination of pairs of eyes we had on this trip produced 

 behavioral information which may have been known previously by 

 this person and that, hut which had not been put together and 

 made understandable and useful. You have heard in the film the 

 shipper action. This is a behavior I have seen often in my training 

 films. I think of it is as sulking. It had to be put together through 

 biologists and fishermen working together. 



Another problem is the stray animals that are deep in this net, 

 away from the backdown area, and go unnoticed until the net is 

 drawn in. James Coe points out that you can easily tell if any such 

 animals have been left behind by sticking your head underwater and 

 listening — they whistle all the time. 



It seems important to have a person checking porpoises from be- 

 low the water surface before backdown is terminated. There is a 

 real hazard from sharks in the net. Our photographer was actually 

 attacked once, so Coe, who performed this task for the ( '.■/. worked 

 from a small rubber raft and he was also, with some practice, able 

 to use this raft to help herd reluctant animals out of the backdown 

 apex to freedom. 



I think perhaps my own principal contribution as a scientist on 

 this cruise was that I was able to verify the fishermen's observations 

 that the porpoises exhibited learned behavior. There were half a 

 dozen observations I made of different schools that convinced me as 

 a porpoise trainer that they were ahead of us. They knew what was 

 happening. 



Mr. Leggett. By that you mean that the porpoise have been caught 

 before and they knew how to get out ? 



Ms. Pryor. I think they did. They knew for example where the 

 background areas are. During the setting of the net. they will take 

 up stations quite calmly. I was surprised at how calm they were. In 

 the middle of the net and as far from the boats as they can get before 

 backdown starts, before backdown started, they went to the back- 

 down area. It reminded me of cattle waiting at the gate. They knew 

 where they were supposed to go. They were cooperating. 



