114 CORMORANTS AND THE GIPPSLAND LAKES FISHERY 
killed. This is what would appear to be taking place in the 
Gippsland Lakes, although probably in a much more complex 
manner with more serious results than I have indicated. I am 
informed that the Streaked Arrow Grass can be obtained at 
the moment (July, 1940) only in a few favourable localities. 
With the completion of the artificial entrance in 1889 the 
more or less constant composition of the waters was destroyed 
and, as a consequence, the very basis of the natural conditions 
of the lakes. There is no available written evidence of the 
effects in the early years, and no record of fish quantities until 
1911, but the process would be a gradual one, successfully held 
in check at times by floods. The greater and more frequent 
the floods the less the possibility of deterioration by the free 
access of sea water. The most beneficial year in this respect 
was 1916, when flooding was severe and prolonged with 
interesting results as shown in the graphs of quantities. 
Towards 1920, however, the effects of what can only be 
attributed to increased salinity were becoming increasingly 
evident. Depletion of aquatic grasses was noted, and what 
was of more immediate concern to the fishermen, by that time 
a crab (Paragrapsus gaimardii (M. Edw.)) had multiplied 
to such an extent as to make the use of mesh nets impossible. 
No sooner were the nets put out when they were attacked and 
destroyed by enormous numbers of these crabs. Until then 
the sunk or mesh net was one of the main methods of fishing ; 
it is not now used except occasionally during flood periods. 
The presence of this crab in such numbers almost certainly 
has resulted from the increased salinity of the lakes making 
conditions suitable for them, and the lack of natural controls 
or opposition has permitted their increase to such an extent 
that they are now a serious pest. 
From about 1920 onwards the fishery has deteriorated. For 
instance, the marketed quantity of Bream for the year 1919 
was more than 700,000 lb.; in 1929 it was 50,000 lb., a drop 
of approximately 93 per cent, in ten years. The highest figure 
since 1919 is 250,000 lb. in 1935, a drop of 64 per cent. To 
attribute this marked decrease to the depredation of Cormo- 
rants is merely to avoid the issue. A reference to the graphs 
will show that the Ludrick, which is completely dependent on 
vegetation as food, has been so reduced as to be non-existent 
from the commercial viewpoint. Another significant fact is 
that the Gippsland Perch was netted in the lakes and marketed 
as commonly as Black Bream in the early years. To-day it is 
practically absent from the lakes; a very few are obtained 
occasionally after floods. The explanation is that the Perch 
