SCOPE OF THE OBSERVATIONS 53 



of the Antarctic Ocean, involving much of the richest of the whaUng grounds, has for six vital months, 

 from June to November, never been visited by our vessels, nor in the nature of things is it ever likely 

 to be. Indeed since the highest latitudes can only be attained in January, February and March, it is 

 clear that much of the region south of the 65 th parallel, and probably everywhere south of the 

 Antarctic Circle, an enormous coastal belt that will be demonstrated later to be of major importance 

 to the whaling industry, is virtually closed to navigation for all but three months of the year — an 

 accident of geography that will always present a problem to Antarctic oceanographers. 



MATERIAL AND DATA 



The material consists of our enormous collection of samples of the whale food, together with its eggs 

 and larvae, which, over a period of 15 years, has been amassed since these investigations began, the 

 principal data, in addition to copious field notes on habits and behaviour, including counts and 

 determinations of the eggs and larval stages, and counts, measurements and determinations of sex 

 and developmental condition of the older animals collected in plankton hauls and from whales' 

 stomachs. I have drawn freely too upon the comprehensive reports by Fraser (1936) and Bargmann 

 (1945), the very large series of egg and larval stage determinations, and of larval and adolescent 

 measurements, published by the former, and the measurements and developmental condition of the 

 8029 adolescent and adult krill dissected by the latter having provided a major contribution to the 

 data, without which the picture presented here of the development, life-history and distribution of 

 this species would be very far from complete. At one time or another the majority of the former 

 Discovery Committee's scientific staflF took part in the measuring, counting and sexing, etc., of the 

 older krill taken in our stramin nets. Of the many however who have contributed to this work, 

 particular mention must be made of our assistant, Mr W. F. Fry, who, while serving in R.R.S. 

 'Discovery II' worked continuously on krill during the two voyages she undertook between 1935 

 and 1939, analysing in the course of his task nearly 3000 stramin net samples. It was he too, handling 

 some hundreds of thousands of specimens, who counted, measured and sexed the vast majority of 

 the krill we gathered, providing much of the basic data from which the development of the older 

 stages of this species has been worked out and contributing much to our understanding of its habit 

 in the sea. In all, the catches of 7339 vertical, and of 5122 horizontal and oblique nets have been 

 examined — a total of 12,461 samples. The vast majority of the vertical samples were analysed before 

 the war, 2253 by Fraser, 1505 by Fry and 3124 by me. A further 457 were analysed by Mr Peter 

 Foxton while serving in R.R.S. 'Discovery II' during her first post-war commission of 1950-1. 



METHODS IN THE FIELD 



Descriptions of the several types of plankton net employed in these investigations and of the manner 

 in which they were used at sea have already appeared in the Discovery Reports, notably in papers by 

 Kemp and Hardy (1929), Hardy and Gunther (1935), Mackintosh and Ardley (1936), Ommanney 

 (1936), John (1936) and Marr (1938). Of the several townets mentioned in these accounts three 

 require some further consideration here since it was through them that the great bulk of the material 

 was obtained. They are the fine silk 70-cm. diameter net hauled vertically and referred to as the 

 N70V, the coarser stramin loo-cm. diameter net towed either horizontally or obliquely and referred 

 to as the N looH or N looB (or sometimes simply as the stramin net) and the so-called Young Fish 

 Trawl or TYF, a large stramin net mounted on a 200-cm. diameter ring which was generally fished 

 obliquely, but occasionally vertically, and referred to as the TYFB or TYFV. In deep oceanic water 

 a routine series of hauls with the N70 V reaching as a rule down to a maximum depth of 1000 m. was 



