Fish Migration 195 



the occasion for endless strife. San- 

 guinary battles by sea and land have 

 been waged by nations, not least our 

 own, jealous to monopolise them. To- 

 day the fishery boards of the world more 

 or less co-operate in attempting to un- 

 ravel the mysteries of fish migration and 

 development. 



No fish are more purely pelagic than 

 the mackerels, a tribe whose graceful 

 forms include such valuable food fish as 

 the tunney and bonito. Spawning takes 

 place in the summer about twenty miles 

 from the shore where the female lays 

 about half a million eggs which drift a 

 little below the surface and hatch in five 

 or six days. Mackerel were believed to 

 retire to the Arctic for the winter, as 

 the herring is still supposed to do by 

 some authorities, and up to the time of 

 Cuvier, it was popularly held that they 

 hibernated by burying their heads in the 

 mud and there rested with the tail 



