DISTRIBUTION AND GENERAL NOTES ON THE SPECIES 289 



It therefore seems quite clear that Patagonian hake really are some 5-0 cm. shorter than European 



hake, and that the disparity would be even more marked if it were possible to compare the males 



separately. 



Another interesting point is brought out by comparison of the length-frequency curves: Patagonian 

 hake, despite their smaller ' average' size, are relatively more numerous in the 50-60 cm. length classes 

 (to the right of the mode) than are European hake. The sharp inflexion above the mode is doubtless 

 due to scarcity of males over that length; but it can be seen that the succeeding flattened portion of 

 the curve is on a distinctly higher level than the corresponding part of the curve for European hake of 

 about 5 cm. greater length. The 50-60 cm. hubbsi—^hont 'ordinary chat' size by Fleetwood market 

 standards of the period-probably correspond physiologically, if not in actual age, to European hake 

 one category larger; so that it seems to me that we have here a striking indirect confirmation of 

 Hickling's proof that the European stock was heavily overfished. 



THE DISTRIBUTION AND RELATIVE ABUNDANCE OF MERLUCCIUS HUBBSI WITHIN 



THE AREA SURVEYED, AND THE EFFECT OF LATITUDE ON 



NUMBERS, SIZE AND SEX RATIO 



The general distribution and abundance of this species cannot satisfactorily be shown on charts of 

 such scale as could be reproduced here, because of its widespread occurrence and pronounced 

 migratory movements. These are essentially similar to the migrations of the European and north-west 

 Atlantic species, as will be shown in a later section. The occurrences of the species at our trawling 

 stations have been tabulated hi exienso in Appendices II A, B and c. From these it can be seen that 

 the most important feature of the general distribution is a marked decrease in relative abundance 

 from north to south. Local concentrations were encountered inshore in autumn (St. WS853, Wb855), 

 offshore in winter (St. WS216, WS217), and at intermediate distances from the coast m early summer 

 (St WS7Q0 WS791). There were, of course, numerous less pronounced concentrations, most ot 

 which tended to conform to the general pattern of migration suggested by the extreme examples 



quoted. . , .... 



Now since hake tend to be more closely congregated when on their inshore spawning migration, 

 and the larger fish tend to move inshore first (cf. Hickling, 1927, P- 59. on the European species), a 

 series of observations in early summer might give an erroneous impression of the effect of atitude on 

 the size of the fish. Spawning takes place earlier in the year in the more equatorial part of the range 

 of the species, and so considerable concentrations of individuals larger than the average for their 

 latitude may be sampled when fish in higher latitudes are not so concentrated. At the same time, 

 moderate numbers of the smaller hake, which do not seem to migrate so far or so fast, can nearly 

 always be found in relatively shallow water throughout the year. In Merlucaus Imbbstj. found that 

 the resultant of these factors completely masked the effect of latitude upon size of fish in December, 

 but this effect was quite clear when the data for all seasons were considered together. A small series 

 of observations in a single longitude taken over a narrow time interval later in the year, when the sma ler 

 individuals were at the peak of their inshore movement, also showed the effect of latitude q-^e clearly^ 

 The general decrease in abundance of hake from north to south of our area is deinonstrated by the 

 figures in Table 11, which are taken from eighty-three hauls spread over the whole of the third 

 survey. Earlier resvdts are m agreement with these, but are not considered here because comparable 

 weight data are lacking : ^ 



