The value of tagging as a marking technique for seals

Abstract

Seals are difficult animals to study because they are inaccessible for much of their life cycle. However, the offspring are born synchronously on land, often in densely populated breeding assemblies. In many species this offers an opportunity to mark them, particularly the young, in large numbers. Marking studies on the Northern fur seal Callorhinus ursinus began over a century ago in Alaska, and since then many techniques have been used (Scheffer, 1950). Tagging was first used to mark Weddell seals Leptonychotes weddelli in 1903 (Hickling, 1962) but was not used in the United Kingdom until 1951. The very first seal tagged, a Grey seal pup Halichoerus grvpus born on the Fame Islands, England, was recovered from Norway—a result which led to sustained enthusiasm for marking schemes at all the major British Grey seal breeding assemblies (see Hewer, 1974).

Dr Summers is a graduate of the Universities of London and Aberdeen. He joined the Seals Research Division in 1972 to study the ecology of Grey and Common seals with particular reference to the assessment and management of British stocks.

Susan Witthames is a graduate of the University of London. She joined the Seals Research Division in 1971 and until recently co-ordinated records of all seal tagging activities undertaken in the British Isles.