308 
BULLETIN OF THE BUBEAU OF FISHERIES 
ence became a decided handicap. Pie undoubtedly did his best, and his report 
contains a large amount of valuable information which has been drawn upon quite 
extensively, but so far as the fate of the seal herd was concerned it did not and could 
not possibly have any influence. It was too late. 
" ' ' Condition of the rookeries in 1910. — Arriving on the Commander Islands in 1910, 
one of Suvorof's first endeavors was to ascertain the actual number of seals on the 
rookeries. Apparently all possible methods of ascertaining the number of seals on 
the Pribilof Islands had been tried, such as calculation of the area occupied by the 
•Dfjfji Fin. 15- — North Rookery, Bering Island, showing distribution of seals in 1910, according to Suvorcf 
herd divided by the theoretical space in square feet occupied by a seal; coimting the 
cows in a number of harems, averaging their number per harem, then counting 
the harems (that is, old bulls) on the rookery; counting from a distance the number 
of seals on a certain area of apparent normal density and then applying the figures 
obtained to the whole rookery. Every one of these methods, however, had to be 
abandoned and the conclusion reached that there is only one reliable method, viz, 
to corral, drive off, and actually count every black pup on the rookery. Their num- 
ber ascertained, the number of the breeding females, only a varying proportion 
of which are present at the same time on the rookeries, is consequently ascertained 
