126 ALASKA FISHERIES AND FUR INDUSTRIES IN 1918. 
At present there is no perfectly adequate means of classifying the 
nonbreeding bulls, and the plan adopted must be continued in spite 
of any faults it may possess. 
CoMPARISON OF HAREM AND IDLE BULLS In 1918 witH 1917. 
Harem bulls. Idle bulls. Total. 
Rookery. 
Gain or Gain or Gain or 
917. | oi, | G9! Or | yo17. | sors. | SAior | o17. | sois, | Gain 
Per cent. Per cent 
82 | + 46.42 182 2 + 9.34 
49} — 9.25 154 149 — 3 
137 | + 5.38 409 443 + 8.31 
13 | — 53.57 61 49 —19. 67 
307 | + 29.53 850 995 +17.05 
90 | + 25.00 256 320 +25. 00 
Sete ateall cs cial is Proc Lo atk sh cac eee 
18 | + 20.00 39 43 +10. 25 
eR euect Seis Saab wescee 312 | + 73.33 851 937 +10. 10 
ee alee ea cbk cole CSB Se bhe Ain cen dice sa Rob dees cl akbucenete G6: secede Joli wtoosee 
AER eae ae 4 Seer 193 | — 43.56 762 687 —9 
Tall da Qa S73 199 | +184. 28 329 542 +64. 74 
A vale SCS EREELE SES 8] — 38.46 35 3b |4.-eeeeees 
RR EN 131}+ .76 296 316 + 6.75 
Polovina Cliffs. .-.... 87 93 59 | + 90.32 118 152 +28. 81 
Little Polovina...... 35 52 — 54.90 86 75 —12.79 
MOrOWA con aascencwncocasees 127 145 + 13.25 210 239 +13. 80 
WOSLOCHNI oc ccccacsccavesee es 1,018 | 1,134 — 32.39 | 1,802 | 1,664 -—7 
LNG] A Se ee Aaa 4,166 | 4,610 
=—=—== | —_———= —_—$$——|{———————— 
NOL Cine bend ae anes sane 266 262 — 43.85 380 326 —14. 21 
Staraya Artil................ 163 160 — 64.60 276 200 —27. 53 
BAPAC ween ees se odecewen= 43 + 17.64 50 63 +26. 00 
SHUN Sa Se Beet eer 6 8 + 33.33 12 16 +33. 33 
AST RCRI- ao coawes ar ocecesece 8 — 16.66 135 144 + 6.66 
LOG a 0 hic eee 135 162 — 63.93 196 184 — 6.12 
AC i ee ee 684 734 — 45.47 | 1,049 933 —11.05 
+10.18 | 2,706 | 2,444 
AGES OF BULLS. 
The age at which a male fur seal is full grown and the old-age 
limit are very important problems which are as yet only partially 
solved. It is known definitely that the breeding age is not reached 
in six years. And if the size at this age is any indication of the 
period of adolescence, full growth may not be reached until about 
the tenth year. This remains to be determined in the future from 
branded animals. 
The maximum age is not certainly known, but has been estimated 
at from 15 to 20 years. The number of breeding years, however, is 
known positively to be as many as five, but not certainly any more. 
Probably the period is shorter when a large number of bulls makes 
incessant fighting a necessity than when they are few and lead a 
comparatively quiet existence. 
The minimum breeding limit of five years has been assumed in 
1918 on account of new information which has been obtained. Ac- 
cordingly, 20 per cent has been deducted for annual old-age loss to 
the classes of bulls. ; 
YEARLINGS. 
Permission was asked for and granted on August 7 for the killin 
of 10 yearling males in order to Es able to add to the meager stoc 
of knowledge of this class. Owing to their rarity on the hauling 
grounds at that time of year, great difficulty was encountered in 
