CORMORANTS AND THE GIPPSLAND LAKES FISHERY 105 
(P. car&o), but I do not consider this even to be a contributing 
factor. Conditions in the waters of the estuary are the 
dominant factors in the case of species whose whole life- 
cycles are completed within the area. This matter is referred 
to more fully following a statement of the results of Cor- 
morant stomach examinations. 
With regard to the spawning of fishes there is an aspect 
which, although elementary, might well be restated here 
because of its great importance to a proper appreciation of 
economic work. A female fish in spawn produces a large 
number of ova or eggs. The number varies with the species, 
and in some instances runs into millions from one fish. It 
will be apparent that if all fertilized ova reached maturity, 
in a very brief time fishes would be so numerous as to make 
life in the sea impossible. Perfect natural interlocking 
controls prevent this, and even in those species in which a 
single female produces millions of ova, on the average, only 
two attain maturity and spawn, thus maintaining but not 
increasing the numbers of any one species. The remainder 
in general are eaten by other organisms either as eggs or at 
some stage before reaching maturity. Probably the least 
among the many natural controls are various species of birds, 
and the common attitude of many people that because a 
certain kind of bird feeds partly or entirely on fishes it is of 
necessity a harmful species, is entirely wrong and inde- 
fensible. This is an indication of what is intended when it 
is stated that under natural conditions a natural balance or 
equilibrium, is maintained. 
Stomach Examination Results. 
Of five species of Cormorants or Shags occurring in 
Australia, four are known from the Gippsland Lakes. They 
are as follows: — 
Large Black Cormorant Phalacrocorax carbo novaehollan- 
diae Steph. 
Small Black „ Phalacrocorax sulcirostris 
(Brandt). 
Yellow-faced Pied „ Phalacrocorax varius (Gmel.). 
Small Pied „ Microcarbo melanoleucus (Vieill.). 
Outstanding in size and numbers is the Large Black, the 
species with which this paper is concerned. Next in numbers 
is the Small Pied, followed by a more meagre population of 
the Small Black, and finally a very few Yellow-faced Pied. 
