SEA-FISHEEIES LABORATORY. 138 



general biological literature, to shew that such samples 

 may not be representative and are, therefore, unreliable 

 because of the manner in which both the physical and the 

 biological conditions may change within narrow limits. 

 This is such a fundamental matter and has such an im- 

 portant bearing upon not only the present issue but upon 

 all our future investigations that it will be well to 

 illustrate it by a few instances. 



Mr. Archer's detailed analysis of the observations taken 

 by the Scottish Fishery Board in the Firth of Forth, has 

 shewn that hauls taken under similar conditions on 

 neighbouring areas may differ very considerably in their 

 results; and the observations made from our own steamer 

 in Luce Bay last November, given by Mr. Johnstone at 

 a subsequent page of this report, demonstrate the same 

 fact. 



The importance of these observations in connection with 

 any proposal to base conclusions upon the results of a 

 comparatively small number of hauls taken at distant 

 intervals over a relatively enormous area like the North 

 Sea, must be obvious. 



We find such an experienced navigator and hydro- 

 grapher as Captain Tizard, R.N., Assistant Hydrographer 

 to the Admiralty, stating in his evidence (in answer to 

 Q. 2,125), that observations taken four times a year 

 across the entrances to the North Sea would not show the 

 nature of the water going in and out at all, that it would 

 be necessary to take observations at much more frequent 

 intervals (2,128), that in a place like the Channel between 

 Dover and Calais the observing stations ought to be very 

 close together, certainly not more than 3 or 4 miles apart 

 (2,141), while in the space between the Orkneys and 

 Norway stations say twenty miles apart would probably 

 suffice, but that would have to be determined by experi- 



