22 OCEAN EESEAECH 



therefore show a year's growth, and by counting them it is 

 possible to ascertain the age of the fish from which they were 

 taken. This theory is not as yet universally accepted ; but the 

 Norwegian and most other naturalists believe it to be correct. 

 A similar record is known to be engraved on the ' otoliths ' or 

 ear-stones and the gill-covers of some fishes — plaice for instance. 

 The scales and the otoliths are in fact fishes' ' identity discs ', 

 and to some extent a record of their wanderings. The import 

 of this discovery will appear again and again in the chapters 

 which follow. Meanwhile two or three points emerge with 

 especial clearness. 



We know that some cod and haddock and herrings Hve to 

 fifteen or eighteen years ; that some of them breed for at least 

 fifteen years in succession ; but, above all, that the stock of 

 fishes does not (like the stock of civilized men) receive an 

 approximately even accretion each year. There are almost 

 incredible differences between the herring and cod populations 

 of one year and the succeeding year ; and these variations are 

 due, apparently, to an infant mortality which in a normal year 

 is, by human standards, cataclysmic. 



On the international work this much comment is permissible. 

 In the first place very little effort has hitherto been made to 

 explain it to owners and officers of fishing vessels as it proceeds. 

 ' Popular ' lectures and ' popular ' publications (hke Hjort's ^ 

 Some Besults of the International Ocean Researches) might easily 

 change the attitude of the industry towards Science from one 

 of puzzled tolerance to one of enthusiastic collaboration, for 

 which, the writer is convinced, the time is now ripe. 



In the second place this desirable result will be hastened 

 eyery time an investigator boards a trawler at sea for a yarn — 

 as is Dr. Hjort's custom, and every time a naturahst is told off 

 for a voyage, or, still better, a series of voyages, on a regular 

 trawler. Men who are to dedicate themselves to fishery re- 

 search should, some time in their novitiate, from a trawler's 

 deck see a whole year's fishing (winter as well as summer) on 

 some of the deep-sea grounds. This contact between natura fists 

 and fishing skippers is particularly necessary in the case of the 

 ships who are still ' feeling outwards ' for new grounds to fish, 

 more especially in the case of the southern hake grounds. 

 The French inquiries on the South- West Banks will no doubt 

 be most valuable, but the industry wants to see British 

 naturalists aboard of vessels who go south ' to meet the 

 hake '. 



* Publishod by the Scottish Ocoanographical Laboratory, 21 Rutland JStreet, 

 Edinburgh. 



