Welsh Journals

SEAL MIGRATION A. L. JOHNSON Some years must elapse before sufficient evidence will have been accumulated, from ringing, on the movements of the grey Atlantic seal to permit such information to be used as the basis for an account of the grey seal's migration. In the meantime, however, a summary of the recoveries of Welsh-born seals reported so far is probably of interest, although it should be borne in mind that the pattern of movement may be peculiar to the Irish Sea-Cornwall group and may change quite considerably when further recoveries, as from the Hebrides and the Farne Islands, are made. The published opinions on migration of experienced seal observers are summarised below R. M. Lockley* and F. Fraser Darlingt are of the opinion that the grey seals' migration takes the form of a general spreading out from the breeding area. R. M. Lockley* believes that a movement greatly in excess of the normal spreading out is undertaken by young seals and that these migrants probably return, when they reach maturity, to the coasts on which they were born. F. Fraser Darling and R. M. Lockley* consider that there is likely to be little, if any, inter-breeding between the various colonies. 283 seals have been ringed in S.W. Wales in the last four years as part of a marking scheme run under the auspices of the Zoological Society of London, and 23 of these rings have been recovered. Six of these reports, however, were concerned with seals less than three weeks old, so it is probably advisable, when considering migration, to disregard these recoveries. (A young grey seal is unlikely to take to the sea as its normal habitat until it reaches an age of about three weeks, though it may be seen swimming at a much earlier age.) The age of the remaining 17 recoveries varied between 3 weeks and 25 weeks, 8 were in the 7 to 8 weeks age group. Thus all the information available so far is on the seal's movements during its first 6 months of life. Five of the seals have been recovered within 1 miles of their place of birth. Two of these were sleeping so soundly that the numbers on their rings were read without the animals being dis- turbed and these rings had not damaged the seals in the least. Two seals reached N. Wales, though both were dead when found. One came ashore near Trearddur Bay in 1952, and the other near Criccieth in 1953. The tide and the wind may have carried these two some distance, but it is reasonable to assume that they had moved north up St. George's Channel. There are reports on 5 seals from Ireland. In 1954, one seal reached the Great Saltee Islands, and one was drowned in a fishing net at Ballycotton. The Ballycotton report is of particular interest