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I.C.T. NISBET 



ever, I think that few of us would disagree 

 that the largest single threat in the area as a 

 whole is posed by oil, not only by the prospect 

 of large-scale drilling for oil on the Alaskan 

 continental shelf but also by prospective 

 spills during transportation and deliberate 

 dumping from ships. 



My guess is that the second most important 

 threat to the seabirds of the northern North 

 Pacific is the presence of introduced preda- 

 tors, especially foxes and rats, at the breeding 

 colonies. Much of the damage inflicted by 

 these predators may already have been done, 

 but I think their continuing presence is likely 

 to have as great a negative effect on the bird 

 populations as anything else discussed at the 

 conference. 



The relative importance of the other identi- 

 fiable threats to the birds is even more conjec- 

 tural. Drowning of diving birds in fishnets is 

 obviously of great potential impact, but its 

 importance depends greatly on the rapidly 

 changing practices of fishermen. This problem 

 must be kept under close surveillance, and the 

 establishment and enforcement of interna- 

 tional agreements will be critical. 



Mineral development has not been men- 

 tioned much. It is my understanding that 

 there are prospects for substantial onshore, 

 and perhaps offshore, developments of heavy 

 metal minerals. These are likely to lead to 

 local disturbance in the coastal zone, and the 

 tailings in particular may well pose a threat to 

 coastal and inshore birds. 



Ocean dumping has not been mentioned. I 

 do not expect that there will be much dump- 

 ing of toxic chemicals from Alaskan indus- 

 tries, but we must remember that this area is 

 downstream from Japan and the Soviet 

 Union. I do not know the current practices of 

 these countries, but the unregulated dumping 

 of toxic substances from some European 

 countries apparently has led to large-scale 

 pollution problems in the North Atlantic. 



On present evidence, persistent pesticides 

 and polychlorinated biphenyls (PCB's) do not 

 seem to pose a significant threat to north 

 Pacific seabirds, although high levels of 

 PCB's have been reported in shearwaters off 

 the California coast. In my judgment, we have 

 probably turned the corner in regulating these 



chemicals, at least in the northern hemi- 

 sphere, and their impact will probably not be 

 allowed to get worse. 



Human disturbance is obviously going to 

 get very much worse, both from the influx of 

 new human populations who will be involved 

 in more industrialized activities in Alaska and 

 from the likely increase in tourism. A matter 

 of particular concern is the prospective influx 

 of natural history tours, which can have 

 major adverse effects if not carefully 

 regulated. 



Finally, we should not forget the impact of 

 natural phenomena, including climatic 

 changes and vulcanism. Bearing in mind the 

 experience of Katmai, we might expect a natu- 

 ral disaster to strike a major bird colony at 

 any moment. 



Practicability of Conservation 



Experience from other countries, as related 

 in various papers at this conference, has 

 shown that conservation of seabirds is pos- 

 sible and practicable, even in remote and inac- 

 cessible areas. We have heard today particu- 

 larly about conservation programs and 

 achievements in Europe and New Zealand. 

 W. H. Drury spoke briefly about experience in 

 eastern North America and F. Salomonsen 

 told us how the bird populations of the 

 Faeroes Islands have been managed for sus- 

 tained yield. 



At least in the North Atlantic, where the 

 history of the bird populations is much better 

 known, the conservation situation has been, 

 and probably still is, very much worse than 

 that now prevailing in the North Pacific. 

 Looking back on 200 years in the North At- 

 lantic, we find that two major marine species 

 have been extinguished, at least one and prob- 

 ably two or three others became endangered, 

 and almost all the seabirds were drastically 

 reduced in numbers (at least in temperate lati- 

 tudes). Starting in the late 19th century when 

 many species first received effective protec- 

 tion, most showed impressive recoveries, but 

 some have declined again in the last 30 years. 



We can learn several lessons from that ex- 

 perience. One is that we can do great damage 

 to seabird populations in a very short time if 



