— 12 — 



The mean average of these numbers is eqnal to 79 and thus considerably 

 higher than the total average 49-4, because the northern areas have got the same 

 influence as the southern ones in spite of the small number of trawl-hours. This 

 mean average would be more representative for the general conditions in the 

 whole North Sea examined, than the total average if the single averages were 

 representative themselves. Though it is possibly still too low, as the northern 

 areas are, upon the whole, larger than the southern ones. • 



The above figures show a distribution according to area, which is very 

 characteristic; and the relation between them seems natural enough, if we consider 

 other information that we possess concerning the haddock in the North Sea. 



The figures may be arranged into three groups: 



1) The Northerly Areas examined, with depths over 30 fathoms 

 (A. B. C. D. E) as well as the area round the Little Fisher Bank (J). In this 

 group of areas the average catch was ca. 150 individuals per hour 

 [t.a => 154, m.a = 142) of which the greatest number was from the Great Fisher 

 Bank (D); then came the area round the Little Fisher Bank with a number 

 equivalent to the average for the whole group. The number appears rather 

 smaller in those parts of the North Sea where the depths are over 50 fathoms, 

 and considerably smaller in the portion lying between The Gut and the coasts 

 of Scotland and North England; though from these areas the material is very 

 scanty. 



2) A strip along the coast of Scotland and North England (F) 

 and the areas east of Flamborough Head including the Dogger 

 Bank and the easterly banks (G. H. O. K), where the depths are less than 

 30 fathoms, show an average catch of a little more than 40 haddock per 

 trawl-hour (/.« = 43, m.a = 41). Within this group there are only small 

 variations between the different areas. 



3) The Southerly and Westerly parts of the North Sea off the 

 coasts of South England, Holland, Germany and Denmark (L. M.), 

 with depths mostly under 20 fathoms, show an average number of only 13 

 individuals per trawl-hour {i.a =^ 13, m.a = 14), or a far smaller quantity 

 than at any of the other areas in the North Sea. 



These figures do not of course lay claim to any absolute accuracy as was 

 pointed ont in the Introduction. But the relation between the numbers shown 

 here is entitled to consideration, and it does perhaps give a fairly correct ex- 

 pression of the differences of average vital-densities per stretch (i. e. the extent of 

 ground covered by a 90-foot trawl in an hour). 



It will appear from what follows that by far the most considerable portion 

 of the individuals are small, that is to say of the sizes which in British markets 

 are called Smalls or Extra Smalls. D'Arcy Thompson's maps showing the 

 weight per catch of small haddocks from various portions of the North Sea (his 

 fig. 26), if we take into account the different nature of his material, will be found 

 to be in accordance with our observations. That portion which is comprised in 

 our area D shows an undoubted maximum weight for Smahs, whereas off the 

 coast of Jutland (our area M) Smalls show a minimum. On the other hand it is 



