295 



Mr. Potter. Mr. Pollock, have you all done any research on the re- 

 lationships between the size and the health of the Alaska fur seal 

 population and what is generally going on in the Bering Sea eco- 

 system ? 



This is, I believe, a rather unique system. 



Mr. Pollock. Are you talking about the fur seals now ? 



Mr. Potter. Yes. 



Mr. Pollock. They migrate all the way down. 



Mr. Potter. I know that. 



Mr. Pollock. All the way down the western coast of the United 

 States and beyond. 



Mr. Potter. "Wlien they come back to the rookeries, they are tied to 

 the rookeries for a period of about 2 months ? 



Mr. Pollock. Well, it varies. The older harem bulls come in first, in 

 the late spring, followed by the females. The younger males come in 

 later. 



Mr. Potter. There is still a long space of time that they are resident 

 in the Bering Sea. 



There is some indication that the increased herring fishery in the 

 Bering Sea is having a substantial effect on the health of the fur 

 seal |x>pulation because it is making it harder and harder for the 

 females get enough of food within a few days of the islands, so the 

 pups are starving. 



Dr. Harry. We do have a little bit of information on this and, of 

 course, there have been tremendous takes of fish from the Bering Sea, 

 and this is a changing situation. 



Mr. Dingell. I am curious if this is not a problem of overfishing. 



Dr. Harry. For the fur seals ? 



Mr. Dingell. Yes. 



Dr. Harry. We were curious about this also and, over a period of 

 years, have weighed pups to see if there is any obvious difference in 

 the weight of them. In other words, are they really going hungry ? 



Also, we have been checking the mortality of pups on land before 

 they go to sea, to see if there has been any change. And there has 

 been nothing obvious shown up in either. 



They are not skinnier. The good condition of the pups is an indica- 

 tion of an adec[uate milk supply which, in turn, indicates that the fe- 

 males are getting an adequate supply of food in the vicinity of the 

 islands. There has not been any great change in the mortality of pups 

 on land in recent years. As a matter of fact, if anything, it may have 

 dropped a little. 



Mr. Dingell. Have you done any tests on heavy metals or pesticides 

 in the carcasses of seals that have been sacrificed out there? 



Dr. Harry, Yes. 



Mr. Dingell. Have you seen any changes in DDT, cadmium, or lead, 

 or any of the other heavy metals ? 



Dr. Harry. We, just got some cadmium analyses back and they had 

 a fair amount of it. 



We have not had a chance to look at it. It is brandnew data. 



We have a good deal of old data on mercury and DDT, and fur seals 

 have a good charge of both of these. As a matter of fact, most of the 

 marine mammals do today. 



Mr. Dingell. Are you doing the study on a fairly regular basis ? 



67-765 O - 71 - 20 



