80 THE FUR SKAI.'^ OF THK PRIBILOF ISLANDS. 



fur-seal rookeries. The surveys of tlic rookeries themselves can not be verified, for 

 the conditions have changed \Yith the reduction of tlie herd, and no permanent hind- 

 marks were left. Not even of t'ne survey of IS'.IO is there left a single recognizable 

 stake or stone to show that it ever existed. All that is left of either survey is 

 the unsatisfactory estimate of the seals based upon it. These surveys should 

 have formed the basis for subsecjuent comparisons of the condition of the rookeries. 

 As such they would have been extremely valuable, but all traces of them have 

 disappeared. 



THE SURVEYS CA>" NOT BE VERIFIED. 



It is therefore not ])ossib]e for us to verify Mr. Elliott's surveys of the rookeries, 

 but his maps giving the shore line of the islands are available as a measure of his 

 work as a surveyor. Of these maps Captain Moser, in his hydrog'ra])hic report ' on 

 the islands in 1890, made certain tests. Of Mr. Elliott's shore line he says: "It was 

 a bad mistit * * * and rarely stood the test of an instrumental angle." He 

 further says of the topography of the maps that "it is so vague and indefinite that 

 it is next thing to impossible to do anything with them; I should call them sketches." 

 If this is true of the fixed and permanent shore line, it is not to be supposed that 

 the changing rookery margins, which were necessarily noted from a distance in the 

 summer and measured in winter, after they had melted away, were more correctly 

 located. 



THE EFFECT OF INAC'CIRATE SURVEYS. 



The correctness of the survey of the rookeries is of vital importance to the 

 accuracy of this enumeration. This importance does not lie in ascertaining the 

 mere length of a given rookery. This can be easily obtained, and in any event a 

 mistake of a few feet or of a hundred feet in the length is comparatively insignificant; 

 but the width of the rookery is another matter. To each one of seven of the ten 

 rookeries of St. Paul Island, Mr. Elliott ascribes an even average width of 150 feet. 

 Two of the remaining breeding grounds have a width of 100 feet each, and the third 

 40 feet. Therefore, for the 40,000 feet of rookery shore line on this island. .'>5,000 have 

 an average width of 1.50 feet.^ Suppose there is an error of but 1 foot in this average 

 width, it is multiplied throughout the entire distance. According to the method of 

 the computation involved this would mean the addition or subtraction of 17,.jO0 

 animals, depending upon the side upon which the error falls. Again, suppose the 

 average width was 140 or 160 feet, this would mean a difference of 175,000 seals one 

 way or the other, as the case might be. 



AN INADEQUATE UNIT OF SPACE. 



But aside from the ((uestion of accuracy in the surveys themselves, Mr. Elliott 

 has assigned an impossible space to each individual seal. His unit of space is 2 

 square feet to each animal, young or old, or 4 square feet for the cows, ignoring the 



' Hydrographio Notes, Captain Moser, Part III. 



- Whatever the average width of each rookery may have been, it is certain that it was not the 

 same for all. Neither now nor at any past time have Tolstoi, Polovina, Vostocliui. the Reef, Kitovi, 

 Lnkanin, and Zapadni had the same "average width." The 150 feet is a guess, and that only. 



