INTRODUCTION AND BREEDING OF FISH. 97 



ing directly into the ocean, go down into the salt water after 

 spawning-time, and return again the next season. Some sea fish 

 have been naturalized in fresh water, and scientists have argued 

 from the character of the fish of Lake Baikal, and especially from 

 the existence of the seal in that locality, that all its inhabitants were 

 originally marine species, and that they have entirely changed their 

 habits during the gradual conversion of this lake — once, as is as- 

 sumed, a maritime bay — into a fresh-water basin.* The presence 

 of the seal is hardly conclusive on this point, for it is sometimes 

 seen in Lake Champlain at the distance of some hundreds of 

 miles from even brackish water. One of these animals was killed 

 on the ice in that lake in February, 1810, another in February, 

 1846,f and remains of the seal have been found at other times in 

 the same waters. 



The intentional naturahzation of foreign fish, as I have said, 

 has not thus far yielded important fruits ; but though this par- 

 ticular branch of what is called, not very happily, jpisciGulture^ has 

 not yet estabhshed its claims to the attention of the physical 

 geographer or the political economist, the artificial breeding of 

 domestic fish, of the lobster and other Crustacea, has already pro- 

 duced very valuable results, and is apparently destined to occupy 

 an extremely conspicuous place in the history of man's efforts to 

 compensate his prodigal waste of the gifts of nature. The ar- 

 rangements for breeding fish in the Venetian lagoon of Comac- 

 chio date far back in the Middle Ages, but the example does not 

 seem to have been followed elsewhere in Europe at that period, 

 except in small ponds where the propagation of the fish was left 

 to nature without much artificial aid. The transplantation of 

 oysters to artificial ponds has long been common, and it appears 

 to have recently succeeded well on a large scale in the open sea 

 on the French coast.:}: A great extension of this fishery is hoped 



* Babinet, Etudes et Lectures, ii., pp. 108, 110. 



f Thompsok, Natural History of Vermont, p. 38, and Appendix, p. 13. 

 There is no reason to believe that the seal breeds in Lake Champlain, but the 

 individual last taken there must have been some weeks, at least, in its waters. 

 It was killed on the ice in the widest part of the lake, on the 28d of February, 

 thirteen days after the surface was entirely frozen, except the usual small 

 cracks, and a month or two after the ice was closed at aU points north of the 

 place where the seal was found. 



X For most valuable facts on this subject see a publication of the Fishery 

 6 



