328 



DISCOVERY REPORTS 



The pooled length frequencies show one strong mode at i6 cm. which probably represents Il-group 

 fish. Hints of submodes at 7 and at 12 cm. may indicate the o- and I-groups. The extreme range in 

 length observed was 6-21 cm. 



The mean depth at which we captured N. jordani was 54 m., and the difference of 28 m. deeper 

 than the mean for TV. canina is statistically significant. The extreme depth range observed was 27-82 m. 

 Thus the depth distribution seems to be very restricted, the species being confined almost entirely 



LENGTH . CMS 



Fig. 36. Percentage length frequencies of Notothenia canina and N. jordani^hte summer 



stations pooled. 



to the lower half of the ' first slope ', not spreading out on to the plain of the shelf or overlapping very 

 much on to the territory of N. canina which, as we have seen, frequents the upper half of the 'first 

 slope'. In our catches the difl^erence in mean length oiN. jordani (13-8 cm.) and N. canina (lo-i cm.) 

 is statistically significant. Possibly we have here an example of the general rule ' larger fish in deeper 

 water '-so familiar within the limits of single species having wide depth distributions-operating 

 interspecifically, for the regional distribution of these two species is so nearly coincident that the 

 difl^erence in depth distribution will be the main factor tending to prevent territorial overlapping 



