
Since these estimates are based on samples of varying sizes 
and accuracy (the commercial-harvest samples are much larger, but are 
based on estimates from the age readings), an unweighted average is 
taken to determine mean escapement, viz., 34 percent. In other words, 
we estimate that 66 percent of the 3-year-old group appears on land 
before the end of the commercial harvest, on July 27. The actual percent 
escapement may also be reduced by a postseason kill, if any. 
Total escapement.--Of the 66 percent of male seals 3 years of 
age appearing on land up to July 27, 91 percent are taken in the commer- 
clal harvest, according to the estimate made in the section on the escape- 
ment through the season. Thus the commercial kill takes (.91) 66 = 60 
percent of the total number of 3-year-old males while it is estimated 
Panes the average 40 percent survive the kill (neglecting any postseason 
kill). 
From table 7 the average 3-year-old kill for 1950-52 is estimated 
to be 38,046. 
. . Average returns of 3~year-old males = 38,046 = 63,410. 
-60 
Average escapement = 25,364. 
Escapement of 4-year males in 1951 
Through-the-season escapement.—-This escapement may be 
estimated from A-tag returns in 1951 (table 26). Again all tagged seals 
observed in the commercial kill were taken, so that this escapement may 
be based on a comparison of those recoveries with the total kill or 
with the tag-lost group. However, it is important to recognize that 
the A-tag returns in 1951 have been modified by the procedure of taking 
all tagged animals in 1950. In particular an assumption has to be made 
about the 104 tagged animals below 41 inches in length that we have 
estimated should have escaped the 1950 kill but for this fact. According 
to the mortality table it may be. estimated that 6 would have died in the 
intervening year in any case. If it is assumed that animals returning 
early as threes continue to do so as fours, and further that males below 
41 inches as threes will fall in the 4l- to-45-inch size range as fours, 
then it may be estimated that the corrected number of A-tag recoveries 
in the 41- to 45-inch size range = 298 + 98 = 396. 
Similarly, it is assumed that 9 of the 10 oversized A-tagged 
seals killed in 1950 would otherwise have been recaptured in 1951. 
Estimated proportion of known-length seals in tagged group above 45 inches 
if no killing for tags had taken place in 1950 
= corrected number over 45 inches x = 
40-inch + corrected number 
41- to 45-inch + corrected number over 45 inches 

161 +9 = 170 = .300 
1+ 396 + 161+9 567 
-62- 
