646 DEPTHS OF THE OCEAN 



{Salmo salar), sea trout (Salvia trtitta), capelan (Mallohis 

 villosus). 



In the southernmost part of our boreal region certain 

 Atlantic pelagic forms are found in such numbers that they 

 may be considered as belonging to the boreal area, though in 

 the main they are Atlantic ; so far the occurrence of these 

 species resembles that of certain bottom fish, like the sole, 

 the turbot, and the brill. The principal forms are : the horse 

 mackerel [Caraitx trachttrus), Clupea alosa, and the anchovy 

 (Engraitlis encrasichohts). 



Certain bottom fishes are often found in mid-water, such as 

 the sharks which pursue the herring shoals, the common dog-fish 

 {Acantkias vulgaris)^ the herring-shark (Lamna cormibica) and 

 the large Selache maxiiiza. Many fishes of the cod family lead a 

 partly pelagic life, especially the saithe, and sometimes also the 

 cod, haddock, and others. A specially remarkable type is the 

 Norway haddock [Sebastes marinus). The pelagic eggs, larvae, 

 and young of economically important fishes, chiefly the cod and 

 flounder families (Gadidse and Pleuronectidae) form another very 

 important section of the pelagic communities. 



When in the year 1900 I commenced my investigations 

 with the newly built " Michael Sars," one of my main objects 

 was to find out to what extent the fishes of the coast banks 

 occurred in the deep mid-water of the Norwegian Sea. A large 

 amount of information regarding this question has been accumu- 

 lated, and we may now classify these animals in four groups : — 



1. Larvae and young organisms which have been carried out 

 by currents, mainly of jelly-fish and cod, saithe and haddock. 



2. Adult coast fish which have migrated ; they spawn 

 on the coast banks, but not over the deep water of the 

 Norwegian Sea, the species observed being herring, cod, 

 haddock, and saithe ; also the squid, Ommatostrepkes todarits. 



3. Adult forms which spawn and occur in all stages of 

 development in the coast waters, and also spawn over the deep 

 Norwegian Sea ; the only species of this kind observed is the 

 Norway haddock (Sebastes viarinus). 



4. Atlantic animals : besides those previously mentioned we 

 have also found the squids, GonattLS fabricii and Architeuthis 

 dux, and the " Atlantic " whales, the " Bottle-nose " (Hyperoodon 

 diodon) and the cachalot (Pkyseter macrocephahis). 



Of these groups I will discuss the three last, leaving the first 

 to be dealt with in the next chapter. 



On the chart (Fig. 482) I have denoted all the localities 



