258 | ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
to 1908 more than 50 percent of the comparatively small number of 
whales then killed were from the Northern Hemisphere, but that in 
1938 over 90 percent were from the south. The actual figures for that 
year were: Total, 54,835; Antarctic, 84 percent; Africa, 5.6 percent; 
North Atlantic and Arctic, 1.4 percent; Japan and North Pacific, 4.5 
percent; other regions, 4.5 percent. 
The number of whales killed before the war was dangerously high, 
and there were signs of substantial depletion of the stocks of blue and 
humpback whales. The evidence for this in blue whales is to be found 
in the decline in the total catch per catcher’s day’s work, in the de- 
clining percentage of blue whales in the catches, in the reduction in 
their average sizes and ages, and in the increasing proportion of im- 
mature whales in the catches (see Hjort, Lie, and Ruud, 1932-1938 ; 
Bergersen, Lie, and Ruud, 1939, 1941; and Mackintosh, 1942). The 
stocks of humpbacks have probably suffered even more than those of 
blue whales. Since they are segregated into separate communities 
depletion is more localized, but the statistics show that it has been very 
severe in the Atlantic sector of the Southern Ocean. The fact that a 
higher percentage of marks is recovered from blue and humpback 
than from fin whales (Rayner, 1940) is further evidence that these 
are the two species most in need of protection. Fin whales still ap- 
peared to be plentiful before the war, but could not be expected to sup- 
port the industry for long on its prewar scale. 
The regulation of the industry is based on the International Agree- 
ment of 1937 and Protocols of 1938 and 1944. The principal pro- 
visions, which are founded on biological information, are limitation of 
the Antarctic whaling season, minimum sizes for certain species, 
geographical limits to the whaling “grounds,” the temporary protec- 
tion of humpbacks, and a temporary limit of the total catch to 16,000 
blue-whale units. The last is the most important, but it is a new 
proposal and is subject to reconsideration. 
VI. FUTURE INVESTIGATIONS 
Although considerable progress has been made in recent years 
there is a large field for future research on the whalebone whales. 
The whaling industry must still offer the most direct means of access 
to whales, and more work on the same lines as before will be needed, 
but new or modified methods of research can be developed, and use 
could be made of some modern technical devices. 
Further investigations by biologists working in factory ships are 
undoubtedly necessary, and have in fact already begun. For prac- 
tical purposes the condition of the stock must be checked from year to 
year, and this is specially important at the present time when whaling 
is being resumed after an interval of some years. More precise in- 
