26 KEPOUT ON THE PRESENT STATE OF KNOWLEDGE 



therefore be compared to tlie winter and summer herrings, both of 

 whicli are spawning fish, when they visit the coasts,* Sars regards the 

 autumn fish, which in Norway are taken in abundance in the fjords, as 

 fish which have left the main shoals in summer to follow the young 

 herring upon which they feed. 



Where do the mackerel go when they leave the coast ? is perhaps the 

 most important question connected with their migrations, to which no 

 certain answer can yet be given. Sars and Brown Goode have both 

 shown that the theory at one time held by some naturalists, that the 

 fish hibernate during the winter at the bottom of the sea, in the neigh- 

 bourhood of their summer haunts, is highly improbable, and it need not 

 be further discussed here. 



There are two alternatives in regard to the matter which are worthy 

 of consideration. 



(1) The mackerel may live near the surface of the ocean at con- 

 siderable distances from land, in regions where they find a suitable sea 

 temperature. 



(2) They may live in deeper layers of the sea, at a greater or less 

 distance — possibly never at a very great distance — from their summer 

 localities, where it is possible that they may find the conditions 

 favourable. 



1. That the mackerel during the winter do not retire to more 

 southerly latitudes, and continue to live according to their spring and 

 autumn habits, near the coast and at the surface, is practically certain. 

 There is no record of the fish being taken either on the coast of 

 Africa or on the American coast, south of Cape Hatteras, during 

 the cold months of the year. 



Kor do any accounts exist of mackerel having been seen at the 

 surface in the warmer regions of the open ocean at any time of the 

 year. If they made these regions their winter home, and preserved 

 their shoaling habits, it is practically certain that they would have 

 been recognised, as the appearance of the shoals is well known to 

 seafaring men, and is quite characteristic. If, on the other hand, 

 the shoals broke up and the fish wandered independently or a few 

 only together, it is possible that they might have escaped detection. 

 This must remain, until the contrary is shown to be the case, one 

 of the possible solutions of the question, although it is not very 

 probable, since were it so specimens would almost certainly have 

 been captured at some time or other. 



2. The mackerel may live in deeper layers of the sea, at a greater 

 or less distance— possibly at no very great distance — from their summer 

 haunts. The facts on the whole seem to point to this conclusion. 



• CUN.NINOJIAM. Nat. Hist. Mark. Mar. Fish., \\. 153. 



