the Residence of certain Fishes. 213 



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about ihree acres, was so frozen over as to admit of skating. As 

 to their quality, it was considered by the fishermen of the Tees, 

 by whom the pond was drawn, that they had never seen " a finer 

 lot of Smelts ;" so that in this case there was no loss of flavour or 

 quality. 



The common pike, Esox Lucius, which is an inhabitant of fresh 

 lakes with us, is also found in the Caspian sea ; proving that this 

 animal among others is indifferent to the quality of the water which it 

 inhabits, and, in this case, permanently so. 



It seems to be unquestionable, that in the Dee and some other 

 Sco.ttish rivers, the comm.op eel, Muraena Anguilla, migrates an- 

 nually to the sea, wherever it has the power of reaching it; return- 

 ing again to the rivers and lakes which it has generally been sup- 

 posed permanently to inhabit. The conger eel, Muraena Conger, 

 which is an inhabitant of the sea. in general, also frequents rivers ; 

 so that, of this genus, there are two at least of which the residence 

 is occasionally convertible. 



The Gadus Callarias,or torsk, is also known to enter the mouths 

 of rivers, so that it can reside at least for a time in fresh waters 

 without injury ; but it is not known to remain in them permanently. 

 That the Gadus Morhua, or common cod, can reside permanently 

 in fresh water, is proved in Shetland. In the mainland, as it is 

 termed, of that group, the inlet called Stromness-voe communicates 

 with an inland fresh-water lake by a channel so narrow as to ad- 

 mit of a rude bridge by which the opposite shores are connected. 

 In this fresh water, cod are frequently taken ; and that the water is 

 perfectly fresh is certain ; as the tide is never sufficient to pass the 

 strait of communication, merely damming the fresh water till the 

 ebb again commences. The inhabitants seem to entertain no 

 doubt that the cod remains there for a considerable time ; but the 

 subject not having particularly .interested them, it remains to be 

 discorered whether their residence is permanent or occasional, or 

 whether they spawn there. If they reside there, even for any length 

 of time, it is probable that this water contains other sea-fishes, by 

 which they are tempted, unless they feed on trout ; but I could not 

 discover that any others had J>eeji found, 



