^*=^-l Davey, T'^psettins the Balance of Nature. i?-; 



1017 J ' ■ ■'"' 



in weight has had upwards of 280,000 eggs taken from it. au<l 

 the absence of enemies allows it to increa,se and consume the 

 natural food of our native fish (shrimps, &c.), forcing them to 

 become mow cannibalistic than they are at present, as the food 

 supply is. after all. the controlling factor. 



The Cormorant is frequently accused of being one of the 

 chief agents in destroying our native fish, and this in spite of 

 the fact that in the early daj^s of Victoria almost every stream 

 teemed with fish. The Cormorant must then have been like- 

 wise abundant, so we see that, although the country was full 

 of Cormorants, the streams were also well stocked with fish. 

 This is where the balance of Nature comes in. Suppose, for 

 instance, that Cormorants fed largely on " yabbies " at the 

 time of the year when the fish were spawning, they would 

 prevent the yabbies from feasting on the fish eggs, to which 

 thev are very partial. If left alone yabbies would undoubtedl}' 

 consume thousands of eggs at one meal ; then surely Cor- 

 morants are entitled to a percentage of the fish that, but for 

 their help in destroying the yabbies, would never have been 

 allowed to hatch. 



The same thing applies to the sea fish. Some years ago the 

 Melbourne Harbour Trust was blamed for the scarcity of fish 

 in Port Phillip Bay. It was stated in the newspapers that 

 the dumping of silt in the Bay from their barges was the cause. 

 I do not believe this to ha\e been the cause of the trouble, one 

 reason being that the Bay is a very large place, and, in com- 

 parison, the amount of silt dumped was small ; but the fisher- 

 man himself is, I think, a contributing cause to the scarcity. 

 By destroying any fish he may capture that are not saleable 

 species, or are regarded as vermin, he upsets the balance of Nature. 

 Take, for example, the case of the Gummy Shark, Mustelus antarc- 

 ticus. The fishermen sometimes use this fish as bait, but, if not 

 wanted for this purpose, they are killed and thrown overboard. 

 I look upon this shark as a fish that should be protected by 

 fishermen as one of his best friends. It feeds chiefly on 

 crustaceans ; its mouth is specially adapted for the purpose. 

 I have taken as many as 45 small crabs out of the stomach of 

 one of these sharks. A great many species of fish in Port 

 Phillip Bay spawn on the bottom, and legions of crabs crawling 

 about search out and devour their eggs, and this fish, provided 

 by Nature to keep these crabs in check, is destroyed. This 

 goes on all the year round. Consequently, the crabs are enabled 

 to breed and multiply in numbers out of all proportion to what 

 they should be, owing to the destruction of this natural check 

 to their increase in the shape of the Gummy Shark. 1 have 

 often watched the fishing-boats arrive at Portarlington, and 

 noticed the enormous damage caused by crabs having eaten 



