I/O Correspondence. [voTxxxHi. 



CORRESPONDENCE. 



" UPSETTING THE BALANCE OF NATURE." 



To the Editor of the Victorian Naturalist. 



Sir, — I was very interested to read in the current issue of the 

 Victorian Naturalist an article on " Upsetting the Balance of 

 Nature," by H. W. Davey, Esq., F.E.S. 



Seeing that the subject is such an important one, and that 

 some of the statements made by Mr. Davey are so emphatic 

 and definite, I thought your Club would be interested to know 

 the result of this Department's experience. 



(i) Re Blackfish. — ^The statement is made in the article that 

 ** the extinction of the Blackfish in the near future .... 

 will be due to the introduction into this country of the English 

 Perch." It is also contended that the English Trout is 

 another cause of the gradual disappearance of the Blackfish. 

 Shall we examine some facts bearing on the question ? In the 

 great majority of our southern creeks, where Blackfish used to 

 be so plentiful, but where now it is difficult to get an odd fish 

 of even six inches in length, no trout or perch have ever been 

 put, while in the tributaries of the Upper Yarra, where trout 

 have been in existence for 30 years, splendid hauls of fine 

 Blackfish are got by those who know where to go for them. 

 Again, take the Deep Creek, from Keilor to Lancefield. This 

 creek has been stocked with trout and perch for a great 

 number of years. In spite of continued heavy stocking of 

 the creek by this Department with trout, as good Blackfish 

 have been obtained therein during the past few years as were 

 ever taken in the early days. This does not look as if the 

 Blackfish is exterminated by the trout and perch. Again, take 

 such streams as the Cockatoo, Cardinia, and Woori Yallock 

 Creeks, in which no trout or perch have ever been liberated, 

 but cvhicJi used to be heavily fished. Many years ago good 

 Blackfish were to be got in these streams ; but what is their 

 condition now ? It is hardly worth while wasting time 

 putting a line into any of them. Two of our best Blackfish 

 streams are undoubtedly the Bun yip and the Gellibrand Rivers, 

 and in neither of these have trout or perch been liberated, and 

 this Department intends to see that none are placed therein — 

 at least, while there are Blackfish there. The reason for the 

 failure of such streams as the Cockatoo and Cardinia Creeks 

 is simply this : that they were fished by hundreds of campers 

 and others on every week-end and holiday, while such streams 

 as the Bunyip, Gellibrand, and the upper tributaries of the 

 Yarra, because they are more remote and difficult of access, 

 are only fished occasionally. 



