TELEOSTEI 193 



were descendants of sea-going trout which had once been in the habit of 

 issuing out of the mouth of the Thames, but which were prevented, by 

 the state of that river of late years, from doing so. 



The problem is very interesting from the point of view of the 

 naturalist. All that I can do in the way of elucidating it is to give as 

 full details as I have been able to obtain of the various species and 

 varieties which have been introduced into the country, and of the 

 dates and amounts of these introductions, so that any future investi- 

 gators may be furnished with a record of facts. 



Atlantic Salmon (Salmo salar) 



For nearly half a century attempts have been made to naturalise 

 this fish in New Zealand waters, and untold sums of money have been 

 expended in theundertakings.as the following record shows, indirectly. 

 Fish have been hatched by the million, and liberated in a great 

 number of the rivers both of the South and North Islands. Glacial 

 streams, rivers from the great lakes, rivers from the Canterbury 

 mountains, rapid streams, sluggish streams — all have been tried. In 

 several cases the same river has been stocked with young fish for 

 many years in succession. In many cases salmon have been reared 

 from the egg, have been kept in confinement till they spawned, and 

 their fry have been liberated — always in the same stream — for a 

 succession of years, by the hundred thousand. The fish have grown 

 well to a certain age in our waters and have then gone to sea in a 

 normal manner, just as they do in European streams, but from that 

 point they are lost. With the exception of two identifications recorded 

 below, not a single authentic instance has been recorded of their 

 return from the sea to the rivers. The fish has absolutely failed to 

 establish itself. Our record is the same as that of Tasmania. As 

 W. Saville Kent, the Queensland Commissioner of Fisheries, said 

 in 1873: 



the attempts to stock Tasmanian streams with the true salmon have utterly 

 failed. The young fish have thriven magnificently until their departure for 

 the sea as smelts, at which stage they have simply vanished from human 

 sight, the warm seas of the South being too enervating for them. 



It is extremely difficult to suggest any explanation of the facts. 

 Mr Kent's explanation is almost certainly wrong. It does not apply at 

 all to the south and east coast of the South Island of New Zealand, 

 the region where most of the salmon have been liberated. A southerly 

 current sets up this coast to the east of Stewart Island and Otago, 

 and the temperature of the sea at all seasons of the year is lower than 

 that of the seas round Britain and Ireland, or on the west coast of 

 Norway. 



T. N. Z. 13 



