220 The salt-water rivers of the Ocean. Chapt. xvi. 



known courses, have a clue to where that spawn was 

 carried ; and be in a better position to trace out why the 

 mature fish sought certain portions of certain sea rivers 

 wherein to spawn at certain times; where the fry are 

 hatched and reared ; and by what counter currents, and 

 wherefore, they return. Mackerel, herring and pilchards 

 are usually in spawn when caught in England; it was 

 therefore thought that they sought our shores for the 

 purpose of spawning. But as it has been concluded that 

 the ova of all these fish float, I believe the shore itself 

 has no connection whatever with their spawning, except 

 in so far as the land effects the sea currents; and my 

 impression is, that it is the character of the sea current 

 or sea river that must be looked to for an explanation 

 of their wanderings. Taking this" clue it would seem 

 feasible, after sufficient research, to map out the journey- 

 ings of a mackerel or a herring, as particularly as that 

 of a salmon. If there were not salt-water rivers in the 

 sea with well defined courses and banks, how could fish 

 know their way about it. They would be liable, one 

 would think, to lose themselves in the trackless vast ex- 

 panse, instead of coming back year after year with punc-* 

 tuality to certain shores at certain seasons. There are 

 reasons for concluding that a salmon knows his way about 

 his own particular river, knows every snag, and stone, 

 and pool, and run, in it from mouth to source, just as 

 well as an old fox knows his own beat. And I can readily 

 believe that a herring knows his way about his sea rivers 

 just as well, and has a regular round which he goes every 



