
Proportion of known-length seals in tagged group 
below 41 inches = _ 154 = 0.124 
1,240 
Proportion of known-length seals in tagged group 
41 - 45 inches = 1,071 = 0.864 
1,240 | 
Proportion of known-length seals in tagged group 
above 45 inches = 15 = 0.012 
1,240 
Proportion of seals in kill below 
4l inches (table 25) =.1,438 = 0.0458 
31,746 
Let x = proportion of the below-4l~inch size group taken in the kill 
ils : ‘ehede OS = .0458 
~124x + .864 + (33) (.012) 
Whence x = 0.34 
» « Proportion escaping out of total hauling-out 
before the end of the commercial kill 
= [1 ~ 0.34] [0.124] + (0.67)(.012) = 0.09 
The exact agreement of this result with that obtained by method 
1 is to be regarded as coincidental in view of the sampling errors 
involved in the estimates. Moreover the fact that some of the 1,438 
seals below 41 inches in length in the commercial kill are 2-year-olds will 
make this method-2 estimate low. 
Postseason escapement.--By fitting a curve to the number of 
seals recovered in each 5-day round during the season, it is possible to 
estimate the numbers arriving after the season closes. Such estimates can 
be based on the tag recoveries or on the total kill for any age class, as 
estimated in turn by means of the tooth~ridge age determinations. The 
most difficult problem is the choice of a satisfactory curve. Among three 
fanilies of curves, the normal, the logarithnic-normal, and Pearson's type 
ITI, the last fits most closely in some situations when the agreement 
between the empirical and theoretical curves is judged by Pearson's chi- 
square test, (sum of differences squared)/(theoretical value). In other 
cases none of these gives a satisfactory agreement. This is due to the 
vagaries of the returns, which are governed by weather and other factors 
and which consequently do not form a smooth series. (Moreover the numbers 
in the age classes in the total kill are themselves estimates with varying 
errors.) The fitted curve mst then smooth the original data as well as 
form a basis for extrapolation, to estimate the postseason escapement. 
Escapement estimates based on the logarithmic-—normal and type-II 
curves are implausibly large, particularly for the 3-year-old class. On 
-60- 
