MIGRATION OF FISH 101 



same reason the carnivorous denizens of 

 the deep cannot live in shallow water ; 

 release from the enormous pressure for 

 which they are fitted would cause their 

 vertebrae to loosen, and would produce 

 the same effect that a man would feel 

 if he were able to ascend to a height 

 of say 56 miles above the earth the 

 air pressure would be absent, and his 

 limbs would consequently be light and 

 loose. 



Naturalists have found on dredging the 

 greatest depths of the Atlantic that the 

 fish, which at the bottom are powerful 

 and hardy, are, upon reaching the surface, 

 likely to fall to pieces on being handled. 

 Fishermen who catch hake from the 

 Atlantic middle depths find the vertebrae 

 loose, and the fish have to be handled with 

 great care on being landed ; whereas the 

 hake when found in the North Sea (which 

 is rare, for these fish usually live in deep 

 water) is more compact. This disproves 

 the idea that the North Sea and Iceland 

 fish descend into the depths of the Atlantic, 

 for shallow- and deep-water fish seldom or 

 never come into contact with one another. 



