208 Transactions.—Z cology. 
vitality sufficiently long to land them here in safety, so far as incubation is 
concerned. But I am convinced that it is a most important point to cause 
the period of incubation after deposit in the boxes on the breeding-grounds _ 
to be as long as possible, or at all events as near to the natural average 
period as can be attained. I believe the average at Stormontfield is 120 
days, and nothing quite so long can be looked for ; but it seems natural to 
suppose that ova landed here, with the certainty of being hatched in a few 
days, perhaps hours, will not have the same chance of producing healthy 
fish as those which experience the acclimatizing influence of two months in 
a cool southern stream during incubation. It may be admitted, however, 
that, by the exercise of very great care in the non-freezing method, the 
temperature may be kept so low as will effect the above end. But, if the 
solid method could, with certainty, be resorted to at the time of spawning, 
the trouble, bulk of stowage, and anxiety on arrival in the Colony would be 
reduced to a mere nothing. 
The management after incubation, and the nursing, is the most im- 
portant point, and is a subject fraught with some difficulties. If it is an 
essential part of the Stormontfield scheme—where the young fish or par, 
are in their natural waters—that they should be carefully tended for one 
and two years, how much more so is it important that they should so cared 
for here, when, acclimatization has in addition to be effected. Remember- 
ing the helpless state the young fish are in for nearly six weeks, with the 
ovum adhering as an umbilical sac, the numerous enemies in the eels and 
crayfish, of which they have to run the gauntlet, and above all, that for 
one and two years they must remain in a helpless condition, before 
migrating to the sea, it is not probable that, of the ten thousand ova 
which have now been distributed in the Waikato and Thames waters, there 
is a reasonable good chance of one returning from the sea as a grilse. 
Very helpless indeed, the young par are, as they are to be seen in the lower 
canal at Stormontfield, in thousands, during May and June, ready to pass » 
into the nursing pond, and such, in unprotected waters must suffer fear- 
fully. This points to the true cause of the Stormontfield success. It is 
not so, because it is a breeding place merely. Its nominal capacity is for 
300,000, its utmost power of production under half a million, the produce 
of perhaps fifty fish, from one spawning bed out of a hundred or two beds 
equally good. Millions of fish are, no doubt, hatched naturally in the Tay 
each year, and that the comparatively small number bred at Stormontfield, 
told favourably on the river, can only be explained on the supposition that 
of the numbers of smolis reared in the river and artificially, the latter bears 
to the former a high ratio. In the ponds, the mortality is small, and loss 
from enemies nil. The smolts when sent to the river, remain there only so 
