230 



DISCOVERY REPORTS 



defined as being the waters fished by whalers working from the land stations or harbours 

 in the Falkland Dependencies, Area II as the Weddell Area, Area III as Bouvet, Area IV 

 as Kerguelen, and Area V as Ross Sea. 



BIOLOGICAL NOTES 



Certain conclusions, which are discussed below, result from examinations undertaken 

 on board the 'Southern Princess' in 1932-3 in the Kerguelen Area (IV). 



external parasites. The skin of all Blue whales taken in the Antarctic is covered with 

 whitish scars of various ages, usually oval, such as were found at South Georgia. All the 

 other external parasites recorded in South Georgia are seen also in Antarctic Blue whales. 



length AT sexual maturity. In estimating the maturity or immaturity of Blue 

 females, the presence or absence of pregnancy and the condition of the ovaries have been 

 taken into account. From the results of one season's work it appears that there is little 

 difference if any between the length at maturity of Blue females caught in pelagic 

 whaling and those taken in South Georgia and Saldanha Bay. 



Mackintosh and Wheeler showed that on the average sexual maturity in South 

 Georgia Blue females coincides with a length of 77 ft. 9 in. (1929). (In the present report 

 all measurements are given in feet. In previous reports the metric system has been used, 

 since it was the natural medium for a study that was in many ways biometrical. It is 

 felt that English feet will prove more acceptable for the present work, chiefly because 

 all statistics of whales and foetuses supplied by the whaling industry are given in English 

 feet, units largely used in Norway in marine matters.) Since whaling measurements on 

 board factories are always taken to the nearest foot, it will be convenient for comparison 

 to say that South Georgia Blue females become mature at an average length of 78 ft. In 

 the material examined in Area IV in one season only there was one whale clearly mature 

 at 77 ft. There were three whales clearly immature at 79 ft. and two at 80 ft. There 

 were fourteen whales in a transition state with ripening follicles on the ovaries. Their 

 length distribution was: 



The length distribution of the three classes of whales is shown in Fig. 2. The obviously 

 mature whales are those which either were pregnant or showed old corpora lutea in the 

 ovaries. The average length of whales at the intermediate stage is 79 ft. and that of the 

 earliest obviously mature, 80 ft. It is highly probable that the latter class had become 

 mature in the previous winter, which, as Mackintosh and Wheeler have shown (p. 443), 

 is probably the usual time for maturity to be reached, and that they had grown a foot or 

 two since arriving at maturity. Six out of the eleven listed were pregnant, and since the 



