MIGRATIONS AND DISTRIBUTION 243 



It is clear that the vast majority of Humpbacks were found between 10 and 40 E and 

 between 80 and ioo° E. They are almost completely absent between 50 and 70 E. 

 Between 10 and 30 W there is a very slight indication of increased catches, and this will 

 be referred to again later. Since we have allowed for the time spent by the factories in 

 each locality, and since in these regions there was no scarcity of other species, it must be 

 that there was in those two seasons a real concentration of Humpbacks between 10 and 

 40 E and between 80 and ioo° E. These are the only two seasons for which the neces- 

 sary catch statistics are available, but it can hardly be doubted that there is a permanent 

 summer concentration of Humpbacks at these points, especially as the phenomenon is 

 amply confirmed by the marking records of the ' William Scoresby ' which are spread 

 over four seasons. 



The various whale-marking voyages of the ' William Scoresby ' are described by 

 Rayner (1940, pp. 250-4). The ship spent four whaling seasons (1934-8) on the pelagic 

 grounds. The first three covered the area between the Greenwich meridian and 105 E, 

 and the fourth the western grounds between io° E and 90 W, including the waters of 

 the Falkland Islands Dependencies and the Bellingshausen Sea. The data are thus 

 distributed over much the same range as those in Table 1 1 but extend a little farther 

 west and not quite so far east. In these voyages it is the practice to cruise over wide areas 

 and mark whales wherever they may be found. The records of whales marked or shot at 

 should therefore be an indication of the whales' distribution. Table 12 is drawn up on 

 the same lines as Table 1 1 . The marking log books give the date, species and position 

 of every whale at which a mark was fired, whether hit or missed. Table 12 analyses the 

 whales shot at. Although a good many whales were shot at more than once a fair number 

 were also marked more than once, and the general results would be much the same 

 whether we go by whales shot at or only whales hit. ' Marking days ' are derived from 

 the ship's log and represent only the approximate number of days spent in searching for 

 whales. To express the number of whales shot at as an accurate function of the time 

 spent in searching for them full allowance should be made for weather conditions, but 

 this would involve a laborious calculation of 'marking hours'; the corrections to 

 1 marking days ' would be trivial and would not affect the conclusions to be drawn. The 

 table includes whales shot at anywhere south of 40 S, but there were very few between 

 40 and 50 S, and although the ship's tracks were if anything a little to the north of most 

 of the factory ships' tracks they were within the zone occupied by the main concentra- 

 tions of whales, and the ground covered is much the same. 



Table 12 and the lower part of Fig. 3 quite obviously confirm the existence of con- 

 centrations of Humpbacks in the same two regions. The group in 80-100 E is much 

 more strongly represented than that in 10-40 E, but the latter is clearly there, and again 

 the species is almost completely absent between 50 and 70 E. Westwards beyond the 

 range covered by the factory ships, there is another obvious concentration. This is be- 

 tween 70 and 8o° W in the Bellingshausen Sea. 



Three major concentrations of Humpbacks are now clearly demonstrated: one 

 between 80 and ioo° E which is not far from the longitude of Western Australia, one 



