No. 2 fuel oil decreases embryonic survival of great black-backed gulls

The great black-backed gull (Larus marinus) is widespread in the northern hemisphere, breeding south to Britain and Ireland on the European side of the Atlantic and to Long Island in the United States where populations have increased markedly during the last 50 years (DRURY 1979). With growing exploitation of oil resources, seabird populations are being increasingly threatened by accidental oiling of individuals and the subsequent contamination of their eggs and young. It is generally agreed that gulls and terns, which spend much of their time airborne, are less vulnerable to oil pollution than alcids and seaducks (BOURNE 1968, VERMEER AND ANWEILER 1975). Nevertheless, oiled great black-backed gulls were sighted after the Argo Merchant spill off Nantucket Island in December 1976, demonstrating that this species of gull can be affected by surface oil (GROSE AND MATTSON 1977). In this paper we wish to report results of two concurrent studies in which eggs of the great black-backed gull were externally contaminated with No. 2 fuel oil.