INTRODUCTION 237 



measured, were sorted into length groups for weighing. Notes on maturity stages of ovaries, stomach 

 contents and parasites of fishes were made as before. In addition, an attempt was made to assemble 

 collections of scales and otoliths from prescribed length groups of Merluccius and Macruronus. 

 Unfortunately, it has not yet been possible to work them out. It is known that they were too small to 

 provide conclusive evidence as to growth rate, but they will give a clue which may help to clarify 

 conclusions drawn from other lines of inquiry that must still be regarded as tentative. 



A series of carapace-breadth and weight records of the centolla crab, Lithodes antarctiais, were 

 kept. These also await examination. Some biometric data on squids (body lengths and weights) were 

 recorded, and a lot of data on the numbers, size, sex and incidence of bopyrid parasitism of Miinida spp. 

 These have been utilized by Rayner (1935) in an important study of the growth of these Crustacea. 

 In their pelagic stage they are predominant among macroplankton animals of the more coastal waters 

 of the area (in due season), a fact observed by the earliest navigators of these waters (see also Matthews, 

 1932). Munida spp. are important as food for fishes, birds and whales. 



The much greater scope of the third survey, especially in more northerly parts of the area, led 

 naturally to more and different kinds of fishes being met with. To the north such forms as Callo- 

 rhyncJnis caUorhynchus, Seriolella porosa and two soles were unfamiliar, and there also the centolla crab 

 was to some extent supplanted by the large red oxyrhynch Libidoclea sp., though at some stations 

 both were found. To the south our fauna list expanded as a result of more extensive observations in 

 the deeper waters of the Falkland trough, and in shoal water close to the mainland. Two macrurids, 

 a ray, Parana signata and Sebastodes oculatus were the principal additions here. Only two species 

 new to science were recorded from the trawling stations, although the third survey was more ex- 

 tensive than the first two combined, and carried out under better conditions with all the added advan- 

 tage of previous experience. By contrast, ten new species were found during the first two surveys. 

 This is good evidence that the gear and methods used were adequate to provide a general picture of 

 that portion of the fish fauna that can be sampled by trawling. The two new species discovered during 

 the third trawling survey were Raja midtispinis and Notothenia macrocephala (Norman, 1937, pp. 20, 

 68). 



A most important addition to ideas gained from previous surveys was the discovery of rough 

 ground at the edge of the shelf in several places, whereas Mr John had been fortunate enough to find 

 fine, clean sand there. This rough ground produced striking examples of specialized distribution of 

 fishes found elsewhere in shallow rocky waters but not on the shelf between. 



The weight records constituted a big advance, and permit of a much better general idea of fishery 

 prospects, the relative importance of potentially useful species, and probable breeding seasons. The 

 observations made by Gunther and Rayner with spring balances seem amazingly accurate, from the 

 consistency of ponderal indices {K) calculated from them. Hickling (1930Z), pp. 7-8) has also shown 

 that very good results can be obtained with weighings made on small ships in rough seas. With less 

 detailed studies in view, Gunther and Rayner were weighing several fish at a time, in length groups ; 

 not individual fishes and organs as weighed by Hickling. Since the individual lengths were almost 

 always accurately known, it is possible that for the calculation of broad mean values, such weighings 

 are better than individual ones. 



A second innovation during the third survey, that of repeat or control hauls, gave valuable evidence 

 on the shoaling of fishes. They also showed that the nature of the bottom changes so gradually on the 

 shelf that little would be gained (from the viewpoint of such studies as these) by a closer spacing of 

 the stations. 



During this survey Gunther recorded his opinion that ' the extreme scarcity of fish in the immediate 

 vicinity of the Falkland Islands is unquestionably due to seals. Seals were frequently met far from 



