64 OBSERVATIONS ON ACCLIMATISATION OF THE TRUE SALMON. 



larger number of fiae fresli run grilse. Neither of these two 

 phenomena can as yet be recorded, though there is yet time 

 for the grilse to put in their appearance, the recent inclement 

 weather, accompanied by much snow water in the rivers, 

 having possibly retarded it. If, however, these grilse do not 

 shortly appear, and still more, if the next autumn and winter 

 of 1888 fails to bring up the main body of spawning fish, 

 the conclusion must, I fear, be reluctantly accepted that the 

 true salmon (Salmo solar) does not find the climatic or other 

 surrounding conditions adapted to its permanent residence in 

 Tasmanian waters. This subject has been dealt with in my 

 recently published report, and wherein I put forward what 

 appears to me to be the most probable interpretation of the 

 phenomenon, namely, that the smolts in their descent to the 

 sea, or after a short residence therein, find the temperature 

 of the water so much higher than that in which the species 

 flourishes in the northern hemisphere that they wander away 

 to colder regions, and do not return to their natal streams. 

 In search of a more congenial clime, they might proceed 

 south towards the southern coast of ISTew Zealand, or to 

 Patagonia or the Antarctic icefields. Or possibly, following 

 a uniformly cold abyssal route, they might reappear upon the 

 shores of Japan or North-Bastern Asia, and in which latter 

 region they would have advanced far towards coming in 

 contact again with the northern representatives of their own 

 race. In this connection it is of interest to remark that some 

 few years since the report was circulated that a large number 

 of salmon had been seen taken on the coast of Japan, and it 

 was suggested at the time that these fish had developed, and 

 possibly migrated there, from fry originally liberated in 

 Tasmanian waters. I should be very glad to receive further 

 and more definite information concerning this reported occur- 

 rence of salmon on the coast of Japan. 



Premising, by way of argument, and in order to account for 

 their otherwise mvstical disappearance, that some such 

 suggested migration of the salmon hatched out and liberated 

 in thousands in the rivers of this colony since the year 1864, 

 has actually taken place, such interpretation is found on 

 nearer examination to be supported by many substantial data. 

 In the first place, quoting from one of our highest European 

 authorities, Dr. Gunther, " Introduction to the study of fishes," 

 we find stated — " the true salmon, Salmo salar, is not subject 

 to variation, and is very sensitive to any change of external 

 condition, and to every kind of interference with its economy." 

 Now, on proceeding to examine the external conditions to 

 which it has been attempted to reconcile this species in this 

 colony, it is found that they differ very materially from those 

 which surround the species in its native waters. As pointed 



