THE OLDER STAGES 131 



Lampanyctus braueri (Lonnberg), the most abundant and widely distributed of the Antarctic Mycto- 

 phids; Notothenia rossii Richardson, ^ a coastal form so numerous in the neighbourhood of South 

 Georgia (p. 132) that recently (Olsen, 1954) two unsuccessful attempts have been made to exploit 

 it commercially; Notolepis coatsi DoUo, a widely distributed^ circumpolar oceanic species, and the 

 more recently described Dissostickus mawsoni Norman which grows to a length of four or five feet. 

 As Electrona, Lampanyctus and Notolepis have repeatedly been recorded in small numbers^ from blue 

 and fin whales' stomachs all three it seems are swallowed fortuitously (Clarke, 1950; Marshall, 

 1954) while feeding on the dense concentrations of euphausians on which the whales are known to 

 browse (see PI. III). 



A new genus of Chaenichthyidae recently described by Nybelin (1947) to which he gives the name 

 Neopagetopsis ionah also appears to be a krill-eater. The specimen he describes was collected from the 

 stomach of a baleen whale somewhere near the Balleny Islands in February 1939 and in his remarks 

 on its probable bathymetric distribution Nybelin says, ' Its stomach was filled with Euphausiids and 

 it was no doubt catching food in a patch of "krill" when together with these, it was swallowed by 

 the whale'. Mr Marshall tells me there are two other specimens of this genus in the Natural History 

 Museum, both from whales' stomachs, 



Tattersall (191 8) records it from the stomachs of Trematomus lonnbergi Regan and Prionodraco sp., 

 and Waite (191 6) from the stomachs of Prionodraco evansii, and it seems likely too that Champso- 

 cephalus gunnari Lonnberg from the South Georgia area is a krill-eater, Lonnberg (1906) recording 

 that the stomachs of the specimens collected by Mr Erik Sorling in 1905 'were filled with the remains 

 of shrimp-like crustaceans (perhaps large Euphausiids)'. C. gunnari may well in fact be a major 

 predator in these island waters, Olsen (1955) quoting reports from whalers that it has been seen off 

 the coast at the surface feeding on the krill in shoals, and mentioning at the same time another 

 schooling species, Pseudochaenichthys georgianus Norman, hooked at the surface near Cape Buller, 

 that was evidently feeding on a swarm. C. gunnari has recently been found to be of considerable local 

 abundance. Next to Notothenia rossii in fact it might be the most abundant of the South Georgia 

 fishes, Olsen (1955), trawling in West Cumberland Bay in the autumn of 1951, once having taken 

 4000 in a single haul. 



The partiality of Notothenia rossii to E. superba at South Georgia is well known to the local whalers, 

 was noted by Lonnberg (1906) and has been recorded on more than one occasion by members of the 

 former Discovery Committee's staff. The late Dr E. R. Gunther, to quote one of them, describes how 

 he saw, lurking beneath a swarm, shoals of large A^. rossii swimming in packs of from twenty to thirty 

 fish in close formation and harrying and devouring the krill above. A fish 70 cm. long taken on a 

 handline was gorged to capacity with the freshly eaten quarry.* In other notes made while watching 

 the krill which have been seen swarming round the Government Jetty at Grytviken, Gunther records 

 the capturing of small adolescent krill by young Nototheniid fish, some 4-7 in. long, suspected of 

 being A^. rossii, and describes how 'Crocodile Fish', Parachaenichthys georgianus (Fischer), lurking 

 near the bottom, would suddenly leap up and dart at and eat the krill overhead. 



1 Nybelin (1947, 1951) now regards this Nototheniid as probably belonging to a distinct subspecies, A'', rossii marmorata 

 Fischer. 



^ Its wide distribution is inferred from the frequency with which its larvae and young stages have been taken in our 

 circumpolar plankton hauls. Full grown adults have never been captured in a townet, the relatively few specimens that have 

 been described having been collected principally from the stomachs of whales. The adults, therefore, are evidently very fast 

 moving animals that readily avoid capture by ordinary slow-moving oceanographical apparatus. 



* Generally from one to a dozen have been found at a time. Mackintosh (1942 a), however, records a notable instance 

 where a blue whale had swallowed no less than fifty Notolepis coatsi. 



* This and other information for which I am indebted to the late Dr Gunther has been extracted from the original logbooks 

 of the Discovery Investigations in which he left many valuable field notes on krill and its behaviour. 



13-2 



