BY W. SAVILLE-KENT, F.L.S. 63 



attending the origin and development of this disease than are 

 embodied in this brief history. 



Proceeding now with the subject of the acclimatisation of 

 the true salmon in Tasmanian waters, it may be remarked 

 that the recommendations already made concerning the con- 

 struction of salt water enclosures for the temporary lodgment 

 of the fish are necessarily brought forward under the suppo- 

 sition that it is considered 'lesirable to maintain a permanent 

 breeding stock of salmon under ai'tifical cultivation, and 

 premising also that the latest attempts to effect the natural 

 acclimatisation of the species in Tasmanian waters, shall, as 

 in fomer instances, be productive for all practical purposes of 

 negative results. Should, as I would be only too glad to have 

 to report to you, the species naturally establish itself from 

 the supplies of fry developed from the " Yeoman " importation 

 and liberated in various rivers of this Colony in the year 

 1885, such special provision for the maintenance of a so- 

 to-say domesticated breeding stock will necessarily be super- 

 fluous. On this point, however, I regret to say we have as 

 yet no very encouraging evidence to adduce. In the British 

 salmon rivers it has been conclusively ascertained that the 

 young salmon change from parr to their smolt, or first 

 migratory condition in varying numbers at the end, respectively 

 of their first, second, and third years, they then repair to the 

 sea and may return to their natal rivers the following 

 autumn as half grown salmon or grilse, ready to deposit 

 their spawn. According to statistics collected by Mr. 

 Dunbar, who annually hatches about 500,000 salmon fry in 

 the Thurso Eiver, Caithness, as recorded in Dr. Day's " Fishes 

 of Great Britain and Ireland," about 8 per cent, of the salmon 

 parr become migratory smolts at the end of the first year, 

 about 60 per cent, at the end of the second year, and 32 per 

 cent, at the end of the third year. It is recorded in the same 

 treatise that through experiments with marked fish, instituted 

 by Mr. Ashworth, at Stormontfield, near Perth, it was 

 ascertained that many of the fish belonging to the first 

 migratory batch returned to the rivers as grilse, weighing 

 from five to nine pounds and prepared to spawn the follow- 

 ing autumn, or, within twenty months only of their deposit 

 in the river in the form of ova. 



Applying these ascertained facts to the case of the Tas- 

 mauian-bred fish, a large portion of the Yeoman fry 

 liberated in the year 1885, should have been, and were to 

 my knowledge, ready to migrate to the sea in the spring of 

 the year 1886, and should have arrived on the spawning ground 

 this past winter (antipodean, June and July) of 1887 weighing 

 ■ several pounds. With the spring now opening out we might 

 also have expected the advent in the rivers from the sea of a yet 



