3i8 J. D. LOCKIE 



THE PROPORTION OF SEALS VISITING THE STUDY AREA 



Much important information has been obtained as a result of the marking of 

 seal pups carried out by Mrs Hickling and her colleagues on the Fame 

 Islands. After independence, dispersal from the breeding colony is rapid, pups 

 having been recovered on the Aberdeenshire coast, on the Faroe Islands 

 and in Norway only a few weeks after birth. Dispersal is mainly northwards. 



I have used the pubHshed recoveries (Telfer & Watt, 1953 ; Hickling et a/., 

 1955; Hickling, 1957, 1959; Coulson& Hickling, i960) for seals of six weeks 

 of age and over. Of seventy-eight recoveries, four were obtained from the 

 study area. 



If the seal pups ringed on the Fames are representative of all pups from the 

 Fames, and if marked seals are neither more nor less likely to be recovered 

 in the study area than elsewhere, these figures will indicate the proportion 

 of first-year seals frequenting the study area. Table I shows that 460 first-year 

 seals were alive in June, 1957. The number present in the study area was 



therefore — X 460 = 24. 



78 



During 1956-8, twenty-two grey seals were submitted to me by the 

 fishing companies in the study area. The ages of these seals have been 

 determined by H. R. Hewer who has kindly allowed me to use data which 

 will be published. The sex and age distribution of these seals is shown in 

 Table 11. 



Table II. Sex and age distribution of grey seals caught in salmon nets 

 (Berwickshire and Northumberland coast) 



Age in years 

 I 

 2 

 3 

 4 

 6 



13 



Females 



8 



4 

 2 



3 



Males 



I 

 2 



Total 



17 



Even in this small sample two points emerge. First, only one out of 

 twenty-two captured seals was mature. Since mature seals do occur about 

 the nets and the estuary of the river Tweed, the capture of grey seals in salmon 

 nets must be highly selective for immature animals. Second, the ratio of 

 immature females to immature males (including young bulls) was 17 : 4. 

 This is likely to be a real difference in sex ratio in the study area because in 

 Aberdeenshire the sex ratio in first year seals captured in nets was 6 



