NATURALIZATION OF SALT-WATER FISHES. Ill 



it possible that tliey may ever be made thriving 

 denizens of fresh water, or otherwise be subjected 

 to the immediate control of man ? It has been af- 

 firmed that they may, and hence we must not omit 

 the subject. It has been contended that this change 

 of habit has been effected in the Common Cod, the 

 Plaice, Flounder, Mullet, and other fishes. The 

 evidence we can adduce on this point must neces- 

 sarily be much curtailed. That the Cod can reside 

 permanently in fresh water. Dr. M'Culloch affirms 

 has been proved in Shetland ; the inlet of Stromness- 

 voe in the Mainland, communicating indeed with 

 ihe fresh-water lake, but by a channel so narrow 

 that the tide is never able to pass the strait of com- 

 munication, but merely dams the fresh water till 

 the ebb again commences. That the water is per- 

 fectly fresh, he says, is certain ; also that Cod are 

 frequently taken in it, and that the inhabitants en- 

 tertain no doubt it is a permanent residenter. The 

 Plaice, Pleuronectes platessa^ according to the same 

 authority, has been carried from the North Sea to 

 the ponds of East Friesland; and with regard to 

 the Mullet, both in Guernsey and Sicily, this strik- 

 ing change seems to have been effected. At one 

 time a number of Grey Mullet, about a finger-length, 

 were placed in a pond of three acres of area, in the 

 Channel island, the w^ater being perfectly fresh : 

 they increased in size, and numerous fishes of four 

 pounds weight have been taken from the pond, so 

 that this experiment is complete and satisfactory. 

 In Sicily the Mullet is cultivated in the lake Biviere ; 



