32 GROWTH OF A FISH SHOAL. [CHAP. i. 



as well, picture the haddock and the herring as being afflicted 

 with perpetual motion as being wanderers from sea to sea 

 and shore to shore. The migratory instinct in fish is, in my 

 opinion, very limited. They do move about a little, without 

 doubt, but not further than from their feeding-ground to their 

 spawning-ground from deep to shallow water. Some plan 

 of taking fish other than the present must speedily be devised ; 

 for now we only capture them and I take the herring as an 

 example over their spawning-ground, when, according to all 

 good authority, they must be in their worst possible condition, 

 their whole flesh-forming or fattening power having been be- 

 stowed on the formation of the milt and roe. I repudiate 

 altogether this iteration of the periodical wandering instincts 

 of the finny tribes. There are great fish colonies in the sea, 

 in the same way as there are great seats of population on 

 land, and these fish colonies are stationary, having, com- 

 paratively speaking, but a limited range of water in which to 

 live and die. Adventurous individuals of the fish world 

 occasionally roam far away from home, and speedily find 

 themselves in a warmer or colder climate, as the case may 

 be ; but, speaking generally, as the salmon returns to its own 

 waters, so do sea fish keep to their own colony. 



Our larger shoals of fish, which form money-yielding in- 

 dustries, are of wonderful extent, and must have been gather- 

 ing and increasing for ages, having a population multiplied 

 almost beyond belief. Century after century must have 

 passed away as these colonies grew in size, and were subjected 

 to all kinds of influences, evil or good : at times decimated 

 by enemies, or perhaps attacked by mysterious diseases, that 

 killed the fish in tens of thousands. At Eockall, for in- 

 stance, there was lately discovered a cod depot, about which 

 a kind of sensation was made perhaps by interested parties 

 in the public prints, but the supply obtained at that place 

 was only of brief duration. This fish colony, which had evi- 



