226 DISCOVERY REPORTS 



were carried out alongside. These vessels had a production capacity of 300 barrels 

 (50 tons) a day (Harmer, 1929), and their tonnage was 3000 to 4000. After the Great 

 War factory ships increased in size and elaboration of equipment and used storage tanks 

 for the oil instead of barrels. Ultimately nearly all the ships came to be equipped with 

 slipways, cut usually in the stern but occasionally in the bows, through which the whales 

 are hauled up on to the top deck. Factory ships are now self-contained, complete with 

 storage tanks, and carrying provisions for several months. Most important development 

 of all, as Hjort, Jahn, and Risting point out (193 1, p. 15), thanks to the slipway which 

 enables whales to be worked up on board, factories no longer rely on the shelter of light 

 pack ice or a natural harbour to facilitate the work alongside but are able to work on 

 the high seas unaffected by moderate changes in the weather. The fleet of catchers 

 derives all its supplies from the parent ship, and the complete outfit is frequently at 

 sea for six months without touching at a port. Tankers bring fuel oil and take away 

 whale oil, so that the production of oil need be limited only by the numbers of whales 

 that can be caught and worked up during a twenty-four hour day. Marshall (1930) gives 

 an account of a season on board a factory ship. The whaling fleet employed in the 

 Antarctic in recent years has consisted of from twenty to thirty ships, ranging from 

 6000 to 40,000 gross tonnage, with a production capacity of 1000 to 3600 barrels a day 

 each (six barrels = one ton). These are owned by Norwegian and British companies. 

 There is in addition one Japanese factory ship. 



It can hardly be doubted that the recent enormous increase in numbers and capacity 

 of the pelagic fleet must have an adverse effect on the stock of whales, and in many 

 quarters it is felt that the danger of serious depletion is becoming acute. An investiga- 

 tion of the composition of the stock of whales in the Antarctic, and any means of 

 measuring the effect of whaling thereon, should therefore be of value. 



scope of investigations. In considering the economic aspects of whaling, size of the 

 stock, state of depletion, and so forth, a wider field than the South Georgia grounds 

 claims our attention, and, since the stock of whales is being attacked in almost every 

 part of the southern circumpolar seas, it becomes necessary to draw the material for a 

 study of the biology of whales from as many sources as possible. Among other data are 

 the reports of two investigators who sailed with factory ships and remained a season on 

 board studying the whales in the same manner as was customary at Grytviken as they 

 were hauled up and dismembered. Marshall visited the Ross Dependency in the factory 

 ship 'C. A. Larsen' in 1928-9, and the writer spent the season 1932-3 on board the 

 'Southern Princess', thanks to the hospitality of the Southern Whaling and Sealing 

 Company. 



The larger and more important part of the pelagic catch has consisted up to date of 

 Blue whales, and in this paper these alone will be dealt with. The urgent economic 

 problems in whaling are then: what is the span of a Blue whale's life; is there any 

 method of assessing the age of Blue whales caught in pelagic whaling ; and what effect 

 has whaling had on the stock of Blue whales in the Antarctic? An attempt is made in 

 this report to answer these questions. That the conclusions are tentative is inevitable, 



