TELEOSTEI 



191 



whether you liberate a Loch Leven trout, a Scotch burn trout, or an Italian 

 trout. He soon loses his identity and becomes a distinctive type (novce- 

 zealandice), a quasi-Italian-antipodean variety. I think there is inherent 

 in most of the forms of Salmonidae a wandering habit, and that in search 

 of a wider range, health and better food, they soon learn the advantages 

 of sea-going habits, some varieties more readily than other. The border 

 line between sea trout and brown trout is very fine in this country and 

 depends really on environment. 



In several hatcheries in this country hybridising various forms of 

 Salmonidae has been purposely carried out, and the fry seem just as 

 healthy as those of pure-bred varieties. For example, at the Opoho 

 hatchery (Dunedin) some 700 hybrids, produced by fertilising brown- 

 trout ova with milt from a male salmon (S. salar), were reared, of 

 which 650 were placed in the Waitati, a small stream a few miles 

 to the north of Dunedin, and 50 were retained in the ponds. The 

 former disappeared, the latter which were strong and lively fish 

 were watched for a few months, and then their identity apparently 

 was lost. There was no further record of them. This sort of experi- 

 ment is futile, unless carried out with the definite object of finding 

 out whether such fish grow to maturity, and are able to perpetuate 

 their hybrid characters, or whether naturally reared fish taken in our 

 streams resemble them. No systematic experiments, such as have 

 been carried out at the Howietown (Scotland) fish hatchery, have 

 ever been conducted in New Zealand. Until careful and exhaustive 

 work in this direction has been undertaken, it is impossible to speak 

 with certainty as to the natural crossing of all the imported varieties 

 in this country, and the emergence of a generalised type. 



Fish have been repeatedly taken in our streams which have 

 puzzled all parties in the colony, and they have been submitted in 

 many cases to expert opinion in the Old Country. I give a few 

 examples to show how difficult the question is. Regarding a fish 

 which was taken in Nelson Harbour in 1881, Sir James (then Dr) 

 Hector said : 



a careful examination shows that it must be classed as a true sea- or salmon- 

 trout, although, as has been found invariably to be the case in Otago 

 specimens, it presents a certain admixture of the characters of the many 

 species into which the sea-trouts from the various rivers in Europe have 

 been subdivided. 



In 1889 the Canterbury Society forwarded a fish to Dr A. Giinther, 

 who reported on it as follows: 



(i) The fish is most decidedly not a salmon. You can always distinguish 

 a salmon by the large scales on the tail; this is an invariable characteristic. 

 Your specimen has thirteen to fourteen scales between the adipose fin and 

 the lateral line; a salmon has eleven, very rarely twelve. The maxillary 



