146 THE STORY OF FISH LIFE. 



their condition, accompanying them on their 

 seaward journey, and prey upon their young 

 companions as they travel ; and I believe that a 

 hungry kelt will devour upwards of forty or fifty 

 smolts in a day. Arrived at the sea, the little 

 fish are met by a fresh array of enemies. The 

 army of gulls is always with them, and these are 

 reinforced by cormorants, divers, and other sea- 

 birds, besides which shoals of ravenous fish 

 await their arrival, and assist in thinning their 

 ranks. It is wonderful that any should escape, 

 and but for the extraordinary fecundity of 

 the salmon they would speedily be annihilated ; 

 but such is their prolific nature that a remnant 

 always survives to return to the spawning- 

 beds and keep up the supply. . . . The food 

 of the smolt during his sojourn in the sea is 

 abundant, consisting chiefly of sand-eels, molluscs 

 and marine insects. The smolts increase accord- 

 ingly very rapidly in size, and in three or four 

 months the fish that came down five or six 

 ounces in weight returns to the river from 

 whence he came, a grilse of from four to six 

 pounds : the grilse being the fifth stage of the 

 salmon's existence. Unless accidentally pre- 

 vented, the grilse always returns to the river 

 from whence it came, and after spending the 

 autumn and winter at home, and providing for 

 the continuance of the family by spawning, as 

 already described, returns as a kelt to the sea in 

 the following year, reappearing the next as a 

 salmon of at least ten or twelve pounds' weight." 

 Oar common stickle-back affords us an instance 

 of that mysterious sporadic migration by vast 



