DISTRIBUTION AND GENERAL NOTES ON THE SPECIES 347 



Most of the shallow-water Nototheniidae are abundant intertidally in summer, moving to slightly 

 deeper water in winter. Thus they parallel the movements of the offshore species Notothenia ramsayi 

 on to the shelf in summer and over the edge in winter. The larger, deeper- water species show increased 

 tendency towards schooling in autumn, and it may be that some of them spawn then. There is a little 

 direct evidence as to spawning time among the small inshore species, but this shows all possible 

 ranges from spring spawning in N. sima to autumn spawning in N. squamiceps, with the possibility 

 of an extended breeding season in N. cornucola. Among larger inshore species, A', wiltoni almost 

 certainly spawns in the autumn at the Falkland Islands (Bennett) but in New Zealand A^ macrocephala, 

 the principal species common to both the Antipodean and Patagonian regions, is said by PhiUipps 

 (1921, p. 123) to spawn in September (spring). 



GEMPYLIDAE 



Thyrsites atun (Euphrasen). During the trawling surveys forty-five adult specimens of this large fish 

 were captured. They occurred at six stations only, and twenty-nine of them at a single one of these 

 (WS847B). All these captures were made fairly close in to the mainland coast in moderately shallow 

 water, in late summer and autumn, and all but one of them in the southern region: 



WS96 I WS833 4 



WS812I I WS847A 6 



WS812II 4 WS847B 29 



The lengths of these fish were very consistent, with the means 97-3 cm. for males (range 87-104 cm.) 

 and 97-8 cm. for females (range 89-112 cm.). Females were more numerous than males, but the 

 numbers are too small to support the suggestion that this is a constant feature, as it is in so many other 

 fishes Similarly, no significance can be attached to the slightly greater lengths attained by the females. 

 At two stations Thyrsites was observed to have been feeding heavily upon Clupea fuegensis and 



Thysanopsetta naresi. . 



These fish were in prime condition: the values for K averaged 0-380, a high figure for a species of 

 such slender proportions. The extreme range of K observed was o-320-o-449- We should expect high 

 values for K in autumn if the stock of Thyrsites off the east coast of Southern America spawn at the 

 end of winter or in early spring, as the species is known to do off New Zealand (Philhpps and Hodg- 

 kinson 1922, p. 94) and oflF South Africa (Gilchrist, 1916, p. 8). 



After the conclusion of the third trawling survey, when the 'William Scoresby' was on passage to 

 Europe, young Thyrsttes were captured in the young fish trawl at St. WS881. This station was worked 

 in the area to the" north-east of the Falkland Islands, which is periodically influenced by mixing of 

 warmer water from the Brazil current to the north with sub- Antarctic water. 



In the regions where Thyrsites is abundant (off South-West Africa and south-eastern Australia) 

 nearly all are caught by trolling, jigging or other forms of line fishing. Very few have been taken m 

 trawls Our records cannot therefore be considered as conclusive evidence of its distribution. Never- 

 theless they show a pattern in time and space so consistent with what is known of the habits of the 

 species elsewhere, that it seems worth while to draw certain tentative conclusions from them. 



It is believed that the part of the Patagonian Continental Shelf with which we are chiefly concerned 

 provides a habitat too cold for Thyrsites throughout most of the year, and that such adults as were 

 captured in the warmer inshore waters in autumn indicated the probable southern limits of the feeding 

 migration of the species. The distribution of Thyrsites off South Africa and New Zealand shows that 

 it favours warmer waters than the hakes (Merluccius) of these locaUties; but although its tolerance of 



