The pelagic distribution of the Fulmar Fulmarus glacialis off eastern Canada has been used to test Fisher's (1952, 1966) hypothesis that Fulmar numbers are controlled by the availability of offal from the fishing industry. Fulmars are abundant on the fishing Banks off Newfoundland but not on those off Nova Scotia; by contrast, they are fairly common in the unfished waters south of Greenland. The Newfoundland and Greenland waters are colder than those off Nova Scotia, and it seems likely that temperature and other oceanographic factors, not fish offal, control Fulmar distribution in the western Atlantic. Since the ringing returns show that many of these Canadian birds are from British colonies, it is possible that fish offal may not be the key factor in the eastern Atlantic either.
Since there are no reliable quantitative data on the Fulmar's diet, it is difficult to suggest a specific alternative. However, the Fulmar is, over much of its range, a cold-water species; it may eventually be possible to interpret Fulmar distribution in oceanographic terms, the key factor being its macroplanktonic food. However, the Fulmar population in the warmer waters of the eastern Atlantic remains an anomaly; it is not yet possible to explain the differences in ecology between the eastern and western Atlantic birds, either in oceanographic terms, or by the availability of fish offal.