GROWTH AND AGE AT MATURITY OF THE PACIFIC RAZOR CLAM 
233 
expansion has been obtained by tlie entry into the field of one new cannery and a 
material increase in the number of difrgers. The fact that in 1924 tAvice the area of 
beach and more than tAvice the number of diggers produced but little more than 
four-fifths of the number of cases packed in 1917 is in itself clear evidence that the 
beds have been overdug. If more pi'oof is needed, it "is furnished by the distinctly 
smaller average size of clams taken and the admittedly larger proportion of mider- 
sized clams. The clams naturally reach as large a size at Cordova as elsewhere. 
At Swickshak, in 1923, a clam less than 5 inches long seldom reached the cannery. 
We have only to contrast this situation with that at Cordova to realize how the 
intensive digging, by taking the older and larger clams, has reduced the average 
size. 
If the entire pack of Cordova had been uniformly distributed over all the years 
from 1916 to 1924, inclusive, this average pa(^k would have amounted to 23,000 
cases. From the present state of the beach it is evident that 23,000 cases per year 
is in excess of what the beds can support. Perhaps 15,000 cases might be taken 
annually without serious depletion, possibly \>ut 10,000, but the data at hand is 
insufficient to determine this. 
It is clear from our investigations that a yield approaching, area for area, that 
of the Washington beaches is not to be expected of those in Alaska. This can 
not be too strongly emphasized, as estimates or expectations based on the produc- 
tion of the Washing-ton beaches, with which most of the operators and diggers 
are familiar, must inevitably lead to disappointment and disaster. In the first 
place, the set of young on the Alaskan beaches has never equaled or even ap- 
proached that on the southern beds. As has been stated, at CojDalis in the fall of 
1923 the small clams averaged over 1,400 per square foot. During 1923 and 1924 
a careful search for the young on all the producing Alaska beds did not reveal a 
single location where a square foot would regularly 3deld even one small clam, 
and only a few of the diggers have even noticed these young, although acquainted 
with them in the south. 
Secondly, the growth is far slower in Alaska. We have shown tliat a length of 
4^2 inches is reached in about three years at Copalis but in six years at Cordova. 
Because of this the recuperative power of the northern beds will be far less and 
the effects of protection will be slower in appearing. For instance, in a sample 
of 152 clams over 4^/2 inches in length, taken at one of the canneries during the 
present season (1924), 109 were hatched prior to the beginning of digging in 
1916; of the remainder 23 Avere hatched in 1916. In other words, 87 per cent of 
the clams now being taken were in the beds by the summer in which canning 
started. Even if we include the undersized clams packed in the last tW years, 
well over 90 per cent of the pack has been of clams already living when cannini;- 
started, and the course of the industr}^ would have been little altered if all spawn- 
ing had ceased at that time. Thus, to an alarming and unrecognized degree, tlic 
industry has been consuming its capital. Wlien the reduced spawning, resulting 
from the reduced number of spawners, begins to make itself felt the pack, even 
though materially reduced, can only be maintained by the ruinous process of 
drawing upon that part of the capital Avhich has never given interest — the youiix- 
before they have spawned. 
