

doulit, that to the death ot' the mother at sea a large part of this mortality is due, but 

 that thi.- i> thi' entire and soli- eau-e is surely LmpOWiblB to maintain after our cxperi 

 of tin- c;.iliir mortality, which sliowed no si-ns of having ceased at ih- time we 

 I'stiiiintfd it. 



I. r u-, make, for comparison with the similar table previously -iven (p. I'll), a 

 tal)le of the later mortality on the various rookeries expired in percentage proportion of 

 the dead pups to the whole number born. 



J'l 1:1 r\i \. .1: 1'roportioii of Pups found Dead in the September October Count (after 

 deduction of the whole number already counted in August) to the whole number 

 born on the scvcril Rookeries. 



Put MB*, 



Tolstoi .... 3*8 



Little I'olaviii'i 

 iiif Kfrt 



iluii- . . 

 . . 



An! 



.. 

 I lock 



III! 







Mna . 



6-3 



-.I. 

 5-7 



10 -3 

 1 1 ( 

 12-0 

 12-3 

 12-7 

 12-8 

 13-3 

 13-8 



The contrast or compari.-on of these two tables is exceedingly interesting to me. 

 \\ still l.a\c a wide discrepancy between the percentages on the different rookeries where 

 should certainly be inclined to look for much closer agreement were a general and 

 distant 'ich as the catch at sea) the only factor in operation. But the order of 



percent: tally different from the preceding one. Differences in the nature of the 



mound have n<,w little effect or none at all. Zapadnie and Zapadnie Reef come near 

 together, as do Ketavic and Lukanncn ; Ardi^nen, Reef, Sea-Lion Hock, and Gorbatch 

 are nearly identical one with another; Tolstoi, which stood all but at the bead, now 

 tends at the bottom. It is curious to note that, with the exception of Little Polavina, 

 all the rookeries at the bottom of the list are on the north and west of the island, and, 

 with the exception of Little Zapadnie, all those at the top of the list are rookeries on the 

 south and east. 



1 <!n not propose to explain all the points that an examination of the statistics 



Miit. while I believe that there are sufficient discrepancies to indicate the 



ence of other factors in the case, yet it would, in my opinion, be useless to deny that 



the figures tend to corroborate the presumption that pelagic sealing is responsible for a 



lar^e part of this autumnal mortality. 



The L'enorai result of our investigation accordingly is that pelagic sealing, instead of 

 being the one and only cause of the whole mortality of pups upon the islands, is in fact 

 responsible for an unknown but considerable fraction oi a fraction which is somewhat over 

 one-half of the whole. 



If, moreover, we require further warning not to ascribe too large a coefficient to 

 the influence of pelagic sealing on the aggregate mortality, we may find it in a com- 

 parison of the sta'i-tics for is;).-, an d 1896. We have every reason to believe that 

 the count was made, for the Island of St. Paul at least, as conscientiou>ly in the one 



as in the other; the numbers are congruent for the rookerie? severally as well as 

 collectively. Yet we have evidence of only some !,('<>() mure dead pups in the former 

 than in the latter year, against a pelagic eate.i in Mehring Sea greater (r/., United States' 

 Treasury Dnc., No'. l'.M2, p. 37, 1807) by nearly i:>,000. 



In"lMl."> the count of dead pups on the islands was made, once for all, in the day- 

 immediately preceding the 10th October. The enumeration on St. Paul bland was 

 evidently systematic and careful, and its results tally very closely with those of 189'i. 



On" St. (Jeorire l>land the count is said to have' been made by .Mr. Ziebaeh. the airent 

 in charge. Mr. / ch reports the finding of M',H]-J dead pup- i where, in l s '.Mi, only 

 were obtained), | that would indicate a mortality of about one-third of all the pups 



born on the island. I can offer no explanation of this stupendous discrepancy. 



The following Table sums up the total mortality of pups reported from the two islands 

 for 1895 and 1896. 

 1 313] 



