154 NEW SOUTH WALES 
ova—at least so far as the Sacramento River is concerned,* In Ger- 
many the same efforts are made as in France, and in Sweden also the 
matter has been taken up very enthusiastically. It is in contemplation 
to commence something of the same kind in New South Wales, not only 
for the introduction of useful European fishes, but also for preservation 
of our own. At the present time the golden perch (Ctenolates auratus) 
has been much spread through the zeal and industry of Mr. Warren, of 
Wagga, who in the summer months transmits small boxes of ova to his 
correspondents. 
It is necessary to mention here that fish ova are subject to many 
parasites which effectually destroy their vitality. These parasites are of 
different familes of fungi and algz, especially a green conferva belonging 
to the genus Q@dogonium. The ova are also very liable to the attacked 
by the small fungus which is so destructive to the common house-fly' 
and. affixes it to our window-panes on a little cloud of floculent threads. 
This is Saprolegnia ferax, and it is the one which seems to be destruc- 
tive to many animals besides fish and flies. It stands on a debatable. 
ground between alge and fungi, a quality which it shares with three 
other genera which infest ova, and these are Achlya, Pythium, and 
Aphanomyces. The only remedy that can be suggested for this mould 
is to have the water used in hatching previously boiled and the gravel 
subjected to the same process, not in any case so difficult as at first 
sight it might appear. Weak solutions of Hyposulphite of soda have 
been suggested, but no results have been published. It is to be hoped 
that the Exhibition in 1883 will help to throw light on this question. 
The use of pisciculture need not be confined to fresh-water fishes ; there are 
many of our sea-fishes to which the art might be most profitably applied—the sea- 
mullet for one. What could be easier or less costly than to supply the drain and 
destruction of that most valuable fish by artificial breeding ? Bacup out a shallow 
space of ground near the sea, the bottom about the low-water level, cut a channel 
of communication with the sea, so that every tide shall flow into it, put a piece 
of perforated zinc or wire netting across the channel soxthat nothing can get in to 
destroy the spawn ; then get a few of the fishes on the point of spawning, squeeze 
out the roe gently with the hand into a tub with a little water in it, upon the roe 
so deposited squeeze the milt of the male fish, then stir gently with the hand so 
that every grain may comeinto contact with themale secretion, place the contents of 
the tub on the sandy bottom of the pond, and cover over with a net to prevent cranes 
and other water-fowl from disturbing the spawn. In the early spring the youn, 
fish will make their appearance, and after a few days’ growth they may be turned, 
out and left to their own resources. By the adoption of such a system the most. 
extravagant waste of the old fish can be readily met. The full-sized roe of a 
single female are estimated to contain nearly 3,000,000 ova, so that the careful 
preservation of the yield of a very few fish would supply all the markets of the. 
world. Under natural conditions the loss of spawn is enormous; by the artificial 
system it is reduced to a minimum. 
There would be little difficulty in keeping up the numbers in the same way of 
any fishes for which the demand was so great as to risk the extinction of the, 
fishery, provided they were fishes which spawned on our shallow beaches like the 
mullet. In that class would be included our best net fishes—the whitings, the 
garfishes, the sole, &c.—R.R.C. . 
It is as well here to draw attention to the larger proportion of eggs in 
the flat-fishes, which render them particularly favourable for pisciculture. 
‘ 
me See Report of the Commissioners for Californian Fisheries for 1878-79. The 
fish is generally believed to be English salmon. Also, Report of the Commissioners 
of Fisheries of Maryland from 1876 to 1880, where very full diagrams, plans, and. 
‘drawings of the fish-hatching apparatus and houses are given. 
