The Future

With the cessation of commercial whaling and sealing in the Antarctic Sector of the Pacific, one is tempted to say there cannot now be any serious threat to the survival of the animals in that isolated region. Indeed, we have seen that for some marine mammals the signs are encouraging — the populations are increasing rapidly (fur seals) or slowly (blue whales), and there are substantial numbers of other species still present (sperm whales, crabeater and Weddell seals).

There are, however, some disquieting facts as yet not fully understood or explained — the well documented decrease in elephant seal numbers at Mac-quarie Island and elsewhere in the Southern Ocean (Pascal, 1985), and the still very small numbers of southern right whales and humpbacks, whale species that have had the longest protection from exploitation.

It now seems obvious that the removal of huge numbers of whales and seals from the Southern Ocean over the past 200 years must have affected the Antarctic ecosystem: the competitive balance is such that a change in the abundance of any one species in the food web can have consequent changes in the abundance of other species. Laws (1977,1981) referred to the possible increased availability of krill and other low-level consumers, such as fish and squid, and warned of the consequences to the Antarctic ecosystem of high levels of uncontrolled harvesting of those species. Already there have been significant depletions of Antarctic and Subantarctic fish stocks, indicating poor management of that resource (see Bed-dington, 1987).

One concern is that extensive harvesting of krill, for example, could reduce the food resources available to the depleted baleen whale populations, and thus restrict their recovery. Krill is potentially the largest resource in the Southern Ocean, and can be marketed whole, processed into proteins and vitamins used in cheese manufacture, or used for fish meal to feed farm animals.

New threats to the Southern Ocean ecosystem include pollution (oil, plastics, abandoned fishing gear, etc.) and environmental changes such as global warming due to the "greenhouse effect", with consequent changes in ocean current patterns.

The conservation of marine mammals in the Antarctic Sector of the Pacific has been commented on by many writers over the past century. It must be emphasized that successful conservation still depends on the dynamics of the Antarctic ecosytem, of which we are still largely ignorant, being constantly addressed through international scientific effort, and a satisfactory international management regime being developed within the Convention of Antarctic Living Marine Resources, which can be enforced under the Antarctic Treaty. The machinery for co-operative research is in place and operating (BIOMASS — "Biological Investigations of Marine Antarctic Systems and Stocks" — isa 10-year non-governmental programme co-sponsored by the FAO and the International Association of Biological Oceanographers), and the IWC conducts research on whales within that framework. There must be continuing international logistic and financial support for such programmes to ensure their long-term survival. The welfare of marine mammals in the Antarctic ecosystem may well depend on them.

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