The Breeding Distribution, History and Population of the North Atlantic Gannet (Sula bassana)

Abstract

The world population of the gannet was 165,000 [plus or minus] 9500 in 1939. In 1834 the world population was of the order of 334,000 breeding individuals, of which approx. 2/3 were on the Bird Rocks in the Gulf of St. Lawrence. Thereafter, there was a steady decrease in numbers, mainly owing to the depredations of man at the Bird Rocks, until about 1894, when the world population was of the order of 106,000 breeding individuals. From 1894 to the present day there has been a steady recovery in numbers and an establishment of new colonies, some large and successful, especially in s.-w. Britain. There is no indication that the present rise in numbers will cease. When small numbers of gannets are present in a colony, breeding is abnormally inefficient. Most of the 22 colonies where the gannet now breeds are entirely protected. In the colonies which are still harvested, over-exploitation does not persist, although it is suggested that the taking of young birds at Sula Sgeir should be arranged in the future under planned limits.