the males. Furthermore, the descending phase of the "catch curve" is 
concave, and thus would ordinarily be interpreted as representing in- 
creasing hunting pressure. Since we know that hunting pressure has 
remained about constant for the past several years, we can conclude 
that it represents instead a decreasing stock of animals. 
Population Status 
The total population of the Pacific walrus is not known. The 
best estimates, however, are on the order of 45,000 (Brooks, 1954; Fay, 
1955, 1957). Of this number, approximately 2,000 to 2,500 are bulls that 
remain much of the year near the Walrus Islands in Bristol Bay. Aerial 
surveys during early May 1958, revealed about 5,000 walruses in the 
Bering Sea, most of which were located north of St. Lawrence Island 
(Buckley, 1958; Fay, 1958). Kenyon (1958b) estimates that 5,000 to 
10,000 passed through Bering Strait on the American side. Thus, some- 
thing less than one-third of the estimated total population is believed 
to occur in waters available to the United States for hunting. 
In addition to the direct estimates of population, there are 
some indirect methods that may be used to estimate the condition of the 
population. The most important of these is the insight into age distri- 
bution provided by the same data used in computing the “catch curves." 
On this basis, 56 percent of the female population is of breeding age 
and capable of breeding. This unusually high proportion of adults is in 
itself indicative of a declining population. 
Fay's (1955) figures show a productivity rate of 0.39 calves 
per adult female per year. Combining this with the fact that 56 percent 
of the females are mature yields a total recruitment of 22 percent for 
the female population. Assuming an equal sex ratio, the recruitment be- 
comes 11 percent per year for the population as a whole. There is every 
reason to believe that the sex ratio is not unity; rather, there appears 
to be a substantial excess of males. This apparent excess of_males prob- 
ably results in part from a preponderance of males at birth /120 males 
100 females, according to Fay (1955)/, and in part from selective hunting 
of females by the Diomede and King Island Eskimos. If there is an excess 
of males in the population, the recruitment rate is even lower than that 
computed above. 
None of the data at hand are conclusive; however, all of the 
fragments of information available point to the same conclusion--a 
decreasing population. To review briefly the evidence for decrease: 
1. There has been a decrease in occupied range, and in the 
number of hauling grounds used. 
2. The “catch curve" of females is concave on the right-hand 
leg; assuming equal hunting pressure, it can be explained as the result 
of a decreasing population. 
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