24 ACCLIMATISATION OF THE SALMONID.f: IN TASMANIA. 



" With respect to the exact nature of the Derwent migratory 

 Salmonoids, there has been much discussion as to whether 

 the <S^. saJar has really established itself or not. The 

 handsome fish which is now so numerous in the estuarv of 

 the Derwent is, within certain limits, a most variable form — 

 some individuals being almost identical in all specific 

 characters with the grilse form of S. salar, while others 

 partake more of the character of the equally valuable 8. 

 t-nitta, and its still more closely allied congener, S. camhricus. 

 It is clear to me, however, that the prevailing form found in 

 salt water is a mean between these, and it is this overlapping 

 of the closely agreeing characteristics of these so-called 

 species which renders it so puzzling to determine to which of 

 them any one individual belongs. The question, which has 

 excited much interest in Tasmania, is confused by the notions 

 of imperfectly infonued jiersons, who, by the use of such a 

 misleading common name as ' bull trout,' have led many to 

 think that we have only succeeded in acclimatising the 

 common brown trout and its varieties in our waters, and 

 they often, in ignorance, speak of our fine migratory fish as 

 if it were a coarse, destructive fish of no value. It is to be 

 regretted, where legislation may be concerned, that erroneous 

 notions should be circulated in this way. By such people 

 the fanciful views of amateur pisciculturists or sportsmen are 

 deemed to be of equal value to the utterances of learned 

 ichthyologists such as Dr. Gunther, whose i>rofound know- 

 ledge forces them to speak with extreme caution. 



"We only know as yet that we have a fine non-migratory 

 trout (the brown trout), and a splendid sea-going migratory 

 salmouoid. The question is, not S. fario veisus S. iruila, or 

 S.fario versus S. salar, but the more difficult one of deter- 

 mining whether the variable, handsome, migratory fish, which 

 is frequently captured far out at sea, is (1) S. trvtia, (2) 8. 

 camhricus, (3) *S'. hrocJnjjHima, (4) S. salar, (.5) all of these in 

 variable numbers, (G) a hvbrid partaking in varying degrees 

 of the characters of the four named s[tecies, or (7) one or 

 other of those named but modified by transfer to a new 

 environment. If the individuals which prevail agreed with 

 or fell within the classified limits of any otie 8i)ecieH we would 

 not have the slightest diHiculty in determining their specific 

 value; Ijut when no one imlivitlual comes exactly within the 

 limits of the written characters, it is necessary that the seven 

 propositions advanced by me should be answered satisfactorily 

 before any ont; can pronounce with confidence on tlie subject. 



" Mr. Allport, who knew very well the niceties of distinction 

 between S. salar and 8. tndta, inclined strongly to the opinion 

 that our Derwent salmonoids are grilse of the former, and 

 not S. irjUta. Dr. Gunther and Professor M'Coy have bad 



