3IO DISCOVERY REPORTS 



enormous, over 80 per cent for the years of life until the animals are adult and about 

 30 per cent per annum after that. The rates for the cows are: 35 per cent in the first, 

 15 per cent in the second and 10 per cent in the third year, that is 73 per cent for the 

 first three years. 



This fur seal sufl'ers considerably from the attacks of the killer whale and, as is well 

 known, spends a large part of each year exposed to the hazards of an extensive migration. 

 On the other hand this species produces the first pup at the age of three years, and 

 branded cows have been seen with pups at the age of 16 or 17 years. The average 

 annual rate of increase at the Pribilof Islands is 5 per cent, but it has been known to 

 fall as low as 3 per cent and to rise to over 11. It is suggested in the section on the 

 economic aspect of Otaria that a rate of increase of 8 per cent per annum may be 

 assumed for the present. 



DAMAGE DONE BY SEA LIONS 



To fish. Complaints have been made from time to time that the sea lions, particularly 

 those from the islands in the approaches to Stanley Harbour, prevent "mullet" 

 (Elegi/ms) and "smelt" {Basilichthys) from coming in to places where they may be 

 caught with a seine net or hand line, or destroy quantities of them. It may be mentioned 

 that the harbour mouth at the place where the islands are situated is three miles wide, 

 and there is no sign at any time of a barrage of sea lions across it. The food of Otaria, 

 as has been said, includes fish, but it feeds very largely on squids and Miinida. 



Although it is no doubt true that the actual presence of a seal of any sort at a place 

 where there is a shoal of fish will disperse them, it seems much more likely that the 

 variations in numbers of the fish are due to factors which have nothing whatever to 

 do with the sea lions. No complaints of the activities of the seals are made when the 

 fish do come in, as they continue to do. Similar complaints have been made with 

 regard to the sea lions of the Pacific coast of North America, referring to the " salmon " ; 

 but investigation has shown that these allegations are almost without foundation and 

 that the diminution has been due rather to methods of fishing. There is not in any 

 sense of the words a fishing industry in the Falklands. 



To penguins. The sea lion has been blamed for the diminution of the gentoo penguin, 

 a species which is much valued for the sake of its eggs and for the real improvement 

 in pasture land which it brings about. There is no proof of the culpability of Otaria ; 

 so far as I have seen birds are not usually eaten ; if they were, neither logger (steamer) 

 ducks nor penguins could maintain their numbers against the onslaughts of the sea-Hon 

 herds in the Falklands. 



The diminution of the gentoo penguin may rather be due to the continuous and 

 merciless robbing of the eggs to which the bird has been subjected for many years. 

 Another factor in the reduction of the numbers of this bird may be found in the 

 epidemics which occur from time to time. 



To tussac grass. Besides the actual beaches Otaria favours the land near them, 

 particularly where tussac grass {Poa flabellata) grows. The animals are fond of going 



