However, I believe that the highest research priority should be given to obtaining basic information on reproductive success and life table data for some representative species. Clearly, we cannot study many species in detail, but in selecting key species for such studies we should pick a variety of ecological types—for example, at least one generalist species and one specialist, one sedentary species and one migrant, one species at a high trophic level and one at a low trophic level.
For the purpose for which we convened this symposium—conservation—I do not think that we need detailed knowledge of the factors which regulate populations. Such knowledge is, of course, of immense biological interest and will ultimately be needed for effective long-term management. However, it does not have immediate or even medium-term relevance to the urgent problems of conservation that we now face. What we do need to do is to set up some long-term studies of a few carefully selected species—preferably long-lived species—so that we can trace the effect of environmental fluctuations on their performance for a long period.
Vulnerability of the Resource
We already understand a number of factors that make some of these bird populations particularly vulnerable to the kind of human activities which we can envisage in the next decade or two. Most of the breeding birds concentrate on islands where they are vulnerable to predators and to human disturbance. Many of them concentrate in flocks on human fishing grounds and over other areas of the continental shelf which are likely to be the focus of human activity in the near future. In particular, some of the birds are known to concentrate in the passes through the Aleutian Islands, where they will be particularly vulnerable to future oil spills. In all these ways the birds are concentrated in areas where they are likely to receive disproportionate impacts from human activity and exploitation.
One point that has been barely mentioned in this symposium is the effect of molting on the vulnerability of some of these populations. The eiders, for example, concentrate on molting grounds in the Arctic. The exact location of these molting grounds may not be fully known, but we certainly know that the birds molt somewhere in an area where they will be vulnerable to oil spills (and also to human hunting if the people who move to the Arctic choose to hunt them). Nor are eiders the only species that are flightless when they molt. Some alcids and loons are also flightless for short periods and, hence, particularly vulnerable to oil spills during molt.
Past Damage to the Resource
In the speech opening the symposium, Assistant Secretary Reed referred to this biological resource as still relatively unspoiled. While "relatively" may be an appropriate word, we do have spectacular evidence of changes and damage to these bird populations. The use of the Aleutian Islands for fox farming seems to me a quite horrifying situation. We know also that the early whalers and sealers exploited seabird populations. Although I know of little specific information about the effects of such exploitation on birds in the northern North Pacific, D. G. Ainley in his survey of historical records from the Farallon Islands has shown very clearly the massive effects of human exploitation of birds, starting early in the 19th century. In our area of discussion alone, one species (the spectacled cormorant) is extinct and another (the short-tailed albatross) became virtually extinct and is still very rare. I believe that one or two southern hemisphere species, which must have been substantial elements in the northern summer bird population, have also been seriously depleted as a result of human activity on their breeding grounds.
Several speakers emphasized the importance of long-term fluctuations in bird populations resulting from natural causes, including some examples from the North Pacific. Other types of human activity must also have had some indirect effects on the birds. For example, whaling and sealing in the 19th century must have provided large amounts of food for scavenging birds and eliminated important competitors for the larger fish-eating birds. A similar experiment is now in progress as the predatory fish are being overfished.
Major Threats to the Bird Populations
We now know enough about the distribution and ecology of the seabirds to identify the major threats to them that are likely to be posed by the projected increase in human activity in the coming decades. The relative importance of these threats clearly varies from species to species and from area to area. However, 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.