330 DISCOVERY REPORTS 



Notothenia guntheri Norman. This small species, named after E. R. Gunther by Norman, is mainly 

 an inhabitant of the plain of the shelf, in the southern region. It was recorded from the intermediate 

 region twice, but is not yet known to occur north of 49° S : 



The depth distribution (Fig. 42, Table 36) is remarkably constant, suggesting that A^. gutitheri 

 frequents the plain of the shelf at all seasons, with little migratory movement. There is no evidence 

 of any migration into deeper water in winter, such as can clearly be shown for N. ramsayi. The effective 

 mean depths for A^. ramsayi and A^. guntheri (151 and 147 m. respectively) are significantly different, 

 but their close similarity masks an extremely wide difference in the dispersion of the depth frequencies 

 from which they are derived. This is demonstrated by the shapes of the depth-frequency polygons 

 in Fig. 42, and becomes fully apparent when the seasonal migration of A^. rajnsayi is shown in detail, 

 when we remember that no hint of any such movement is given by our records of A", guntheri. It is 

 interesting to note that the seasonal migration of A^. ramsayi is reflected in a dumbbell-shaped polygon 

 when the results of all seasons are lumped as in Fig. 42, just as was found with Raja brachyurops, a 

 ray which also migrates over the shelf edge in winter (Fig. 18). By contrast the non-migrating Noto- 

 thenia guntheri shows a very squat kite-shaped polygon reflecting the narrowness of the depth range 

 over which that species was observed. 



A^. guntheri has not yet been recorded outside the area of our trawling surveys. Little can be deduced 

 from our measurements of the species beyond the fact that it seems to be a small one ; our largest 

 specimens were 20 cm. long. Unlike the small species inhabiting shallow depths it was captured 

 almost entirely in the trawl, so that all but the largest specimens were presumably outside the selective 

 action of the gear used. A strong mode at 16 17 cm. in the only large catch may indicate a year class, 

 probably the largest well-defined one (perhaps Il-group). There is just a hint of another at 12 cm. 

 (? I-group), which suggests a growth rate similar to that of other Notothenia spp. of comparable size. 

 There is also a slight suggestion of conformity with the behaviour of several other members of the 

 group in the fact that the only considerable concentrations of A^. guntheri were met with in autumn, 

 whde at several summer stations it was taken singly, suggesting wide dispersal at that season. 



Notothenia ramsayi Regan. This was the commonest fish trawled by us in the area investigated: 

 9665( + ) individuals were recorded, a number which just exceeds the combined totals for Macruronus 

 (4953) and Merhiccius (4704). As a result of the smaller size of the Notothenia, however, the weight 

 of hake taken was five times as great, while even the slender Macruronus weighed 2^ times as much. 

 It is of course highly probable that the Falkland herring is present in vastly greater numbers than 

 even Notothenia ramsayi, but we have no means of assessing the relative abundance of such small 

 semi-pelagic clupeoids vis-d-vis demersal fishes. Captures of A^. ramsayi in the ' Trawl + accessory 

 nets ' were as shown on opposite page. 



It can be seen that A^. ramsayi was very widely distributed over the plain of the shelf, and (in 

 autumn and winter) beyond the shelf edge. Unlike most of the nototheniiformes caught in the trawl, 

 which show a strong preponderance to the southward, this species appeared to be almost equally 

 abundant in the northern and intermediate regions. 



The smallest individuals were found mainly to the north in relatively shallow water, but fish almost 

 certamly less than two years old were plentiful at times in the southern region. The larvae, presumably 

 denatant, must be carried northwards by the prevailing current, and it is thus probable that the fry, 

 by tendmg to work inshore, are assisted southwards by the counter-current. Without some such 



