452 



DEPTHS OF THE OCEAN 



flounder, and dab — are the most characteristic, but young stages 

 of cod, rays, and dog-fish (Acantkias) also occur plentifully. 



In medium depths, from 40 to 100 metres (25 to 50 fathoms), 

 the gadidae — haddock, large cod, pollack, and whiting — pre- 

 dominate, but we also meet with flat-fish, turbot, lemon sole 

 {P/eiironectes microcep/ialiis), and young halibut, and with some 

 southern forms : hake, gurnards, anglers, and conger eels. 



Below 100 metres (50 fathoms) we meet with the saithe, 

 ling, tusk (see Fig. 313), large hake, besides witch, megrim, and 

 large halibut. 



Fig. 313.— The "Michael Saks fishing Ling and Tusk in the deep part of 

 THE North Sea. 



Different physical conditions accompany these characteristic 

 differences in the distribution of the fish ; for instance, the 

 depths from o to 40 metres are the ones mainly influenced by 

 summer temperatures ; on the shallow coast banks and on the 

 Dogger Bank the temperature at the bottom rises to at least 

 12° C. in the summer season. The sole may thus find here 

 temperatures similar to those off the Atlantic coast of Europe, 

 though in somewhat shallower water. Below 40 metres the 

 summer temperature is not much higher than the temperature 

 during winter, viz. between 6° and 7" C. 



The species inhabiting the deeper areas of the plateau 

 extend out towards the deep basin of the Norwegian Sea until 



